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Parallel Paths: A Study in Biology, Ethics, and Art

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Title: Parallel Paths: A Study in Biology, Ethics, and Art

Author: T. W. Rolleston


        
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*** START OF THE PROJECT GUTENBERG EBOOK PARALLEL PATHS: A STUDY IN BIOLOGY, ETHICS, AND ART ***

    PARALLEL PATHS

    _All Rights Reserved_

    PARALLEL PATHS

    A STUDY IN
    BIOLOGY, ETHICS, AND ART

    BY

    T. W. ROLLESTON

    “Il faudrait, en un mot, suivre la grande route si profondément
    creusée ... mais il serait nécessaire aussi de tracer en l’air un
    chemin parallele, une autre route, d’atteindre les en deça et les
    après, de faire, en un mot, un naturalisme spiritualiste; ce serait
    autrement fier, autrement complet, autrement fort.”

                                                        J. K. Huysmans.

    LONDON
    DUCKWORTH & CO.

    3, HENRIETTA STREET, COVENT GARDEN
    1908




PREFACE


In a recent work by an eminent man of science, Dr. J. Reinke, Professor
of Botany at the University of Kiel, there occurs a passage which
I cannot do better than place in the forefront of this book as an
indication of its aim.

    “Physiology,” writes Professor Reinke, “has become the study of
    the movements which, taken together, make up life. There is no
    manner of doubt that nourishment, metabolism,[1] reproduction,
    development, and sensation rest on processes of movement which
    depend on material systems of peculiar molecular conformation. For
    the bodies of plants and of animals are material systems whose
    conformation is of a most intricate character.

    “So far as physiology has at present advanced in the analysis
    of these phenomena of movement, their problems have fallen
    naturally into two groups. The first of these groups of phenomena
    is comparatively transparent, and stands in agreement with the
    general processes of the material world; it can be investigated by
    observation and experiment. We may, therefore, hope to decipher
    it completely, and to reduce it, in the end, to chemico-physical
    processes. Of this kind are the phenomena of nutrition, taking
    that word in its widest sense. But behind these processes there
    stand the facts of development and of reproduction, and here, in
    all investigations, and in spite of every attempt to demonstrate a
    basis of physical energy, research finds itself confronted by an
    _X_, a factor which mocks every effort to explain it by physics
    or chemistry. And this _X_ which lurks in all the phenomena of
    development takes a part in the nutritive processes also; so
    essential a factor does it appear in all the processes of life that
    chemical and physical forces alone would not suffice to keep alive
    even the most rudimentary of organisms, not to mention creating
    such an organism out of non-living chemical constituents.”[2]

If this _X_ force exists and can be established, it will give us the
clue, I believe, to much more than the operations of physical nature.
The following pages are an attempt to establish it, to define its
character, and to indicate the lines on which this unknown factor
in evolution seems to bring into a rational unity the phenomena of
the physical world and the moral and æsthetic faculties of man. The
time appears to have come for such an attempt. The fermentation of
mind produced by Darwin’s massive and victorious promulgation of the
evolution theory is beginning to subside; it is now possible in some
measure to take stock of what has been destroyed, of what has been left
intact, by the immense tidal wave of new thought which then swept over
the world. Some conceptions which were thought to have been submerged
for ever are reappearing in more or less altered shapes, and science
is called on to reconstruct a universe less one-sided, less aridly
simple, than that which Darwinism, as at first understood, appeared
to have left us. The result, so far as it is successful, will be the
establishment of a spiritual view of the universe on a natural basis.
It is an attempt which is at present occupying many minds, and which
will doubtless have to occupy many more before complete success is
attained.

I propose, in the following pages, to take the reader over the most
material and significant part of the ground by which I have myself
travelled towards certain conclusions. Much of this ground lies in
the region of biological science. No doubt to readers acquainted with
that science I shall often seem to delay too long in well-trodden
and familiar paths. But I have had to consider the fact that English
education is still very much specialized. It is either literary or
it is scientific. In the great majority of cases it is literary.
And though scientific problems and theories are understood by every
educated man and woman to be of deep importance and interest, and
though questions like those discussed in the present work are questions
on which all such persons are well entitled, and many feel themselves
bound, to have an opinion, very few, comparatively, have even the
elementary knowledge of science and its terminology necessary to
enable them to take up the discussion at an advanced point. When it
is announced from time to time that some chemist has again succeeded
in forming an organic compound out of inorganic chemical constituents
in his laboratory,[3] how many readers are there out of the small
circle of trained chemists who would not be far more impressed if they
heard that he had made a diamond? It is for these persons—the layman
and the lay-woman in point of science—that I mainly write, and my own
training having been philosophical and literary rather than scientific
I think I understand most of their difficulties. I have, therefore,
tried to ‘begin at the beginning’; and I hope that this book, besides
whatever value its conclusions may have, will prove useful to some
readers by putting them in a position to appreciate the extraordinarily
interesting and fruitful discoveries of biology in recent years.

“The lotus of physics,” as Schopenhauer says, “is rooted in the soil
of metaphysics,” and if these studies pretended to offer a complete
explanation of the riddle of existence, the metaphysical basis for
the speculations contained in them would have to be elaborated at
considerable length. But, after all, the conclusions reached would
only be those which most people are willing to accept as a necessary
assumption, if all thought on the constitution of the universe is
not to be a pure futility. Suffice it to say Man is here regarded
as an organic part of Nature, and his consciousness as Nature’s way
of mirroring herself to herself. Since, like other natural things,
the soul is not a complete and unalterable entity, but is part of
the eternal Becoming, it never can be claimed that its reflection of
the world is absolutely pure and complete, yet some reality, some
significance this reflection must surely have. The fact that man is
not something different from the world, observing it from outside,
but is vitally related to it, would alone entitle us to believe that,
however much his observations may need to be purified and corrected,
and however false may be the argumentative deductions sometimes drawn
from them, he is still capable of a real and fruitful apprehension of
the phenomena by which he is surrounded, and of their relations to
each other and to himself. All sincere thought must therefore tend to
brighten a little the mirror of the human soul. If this book should
do so in any degree, were it merely by provoking other minds to more
successful labours, the writer will thankfully say, like Apollo’s
temple-sweeper in the play of Euripides, Fair is the service of Light.

T. W. ROLLESTON.

Glenealy, Co. Wicklow.

_I have to thank The Macmillan Co. for permission to reproduce two
illustrations (Figs. 1 and 2) from Wilson’s_ The Cell in Development
and Inheritance, _and Mr. Edward Arnold for a similar favour in regard
to Fig. 3 from Weismann’s_ The Evolution Theory.




CONTENTS


    PART I. BIOLOGY


    CHAPTER I

    The Argument from Design

                                                                   PAGE

    Paley and the Watch                                               1

    The Analogy Inapplicable                                          4

    Paley’s Conception of Design                                      8

    The Evolutionary Conception                                      11

    Conquest of Nature by the Evolution Theory                       16

    The Philosophic Basis of Nature-study                            17


    CHAPTER II

    The Wheel of Life

    Continuity of Animal, Vegetable, and Mineral Life                21

    Characters of Organic Life                                       23

    Living Matter: Its Functions                                     24

    Its Substance                                                    27

    Its Structure                                                    28


    CHAPTER III

    De Minimis

    Growth and Development                                           32

    Development a Cell-problem                                       33

    The Mechanical Conception of Life                                34

    The Cell and its Structure                                       38

    Cell-division and Heredity                                       40

    Reproductive Cells and Body-cells                                45

    The Origin of Conjugation                                        46

    The Mechanism of Conjugation                                     51

    Significance of Elementary Vital Processes                       59

    Adaptability, a Fundamental Character of Life                    63


    CHAPTER IV

    The Mechanical Theory of Evolution: the
      Darwin-Lamarck Explanation

    The Fixity of Species, how Maintained                            66

    The Mutability of Species                                        67

    Lamarck’s Explanation of the Origin of Species                   68

    Natural Selection of Innate Variations                           72

    Difficulties of Lamarckism                                       77

    Need of a deeper Explanation                                     89


    CHAPTER V

    The Mechanical Theory of Evolution: the
      Darwin-Weismann Explanation

    Lamarck, or ‘Metaphysics’?                                       91

    Weismann’s Escape                                                93

    The Struggle among the Determinants                              95

    Chance-Variations and Co-adaptation                              97

    Other Difficulties of the Chance-Variation Theory                99

    Natural Selection                                               103

    Impossible before Competition Existed                           104

    Co-operation and Competition                                    104

    Protective Mimicry, Inexplicable by Chance-Variations and
      Natural Selection                                             106

    Innate Capacities of Life                                       109

    Outline of Preceding Arguments                                  111


    CHAPTER VI

    The Directive Theory of Evolution

    Nature’s Power of Response                                       115

    Reinke’s Theory of Dominants                                     120

    Cases of their Action in Evolution                               123

    Law and Directivity                                              128

    Intelligence and Directivity                                     130

    The Analogy of Social Evolution                                  131

    The Analogy of Language                                          133

    Synthetic Movement of the Cosmic Reason                          137

    Objections from Imperfect Adaptations and Regressive Forms
      Stated                                                         143

    Mechanical and Psychic Agencies, how Distinguished               146

    Science versus ‘Mysticism’                                       150

    Reply to Objection from Imperfect Adaptations, etc.              152

    Man, the Growing-point of Earthly Life                           154

    Immanence or Transcendence of the Cosmic Reason?                 155

    Man’s Relations to the Whole                                     157


    PART II. ETHICS


    CHAPTER VII

    Law, Free Will, Personality

    Free Will and Determinism                                       161

    The Determinist Position                                        163

    The Free Will Position                                          164

    Conditions necessary for Free Will                              168

    Has the Will an Ethical Bias?                                   169

    Limitations of Free Will                                        172

    Evolution of the Will                                           174

    Free Will and Monism                                            176

    Free Will and Brain-structure                                   177

    Relations of Mind and Matter                                    186

    Immortality                                                     189


    CHAPTER VIII

    The Ethical Criterion

    The Visible and the Invisible Worlds                            194

    Dualism and Monism                                              195

    Monism and the Moral Law                                        198

    The Hedonistic Basis of Morals                                  200

    The Natural Basis of Morals                                     203


    CHAPTER IX

    The Ethical Sanction

    The Individual and the Whole                                    208

    A Scale of Motives                                              210

    Conscience and its Commands, how respectively Derived           211

    Results of Duty and of Self-indulgence Compared                 212

    The False and the True Asceticism                               214

    Ethics for Life: Implications of this Doctrine                  220

    Is Life Dependent on Matter?                                    222

    The Cosmic Life gives Immortality to the Individual             225

    And Demands his Allegiance                                      226

    Ethics Originates in the Visible Order, but does not
      end there                                                     228

    Hence, Ethics is for Death as well as Life                      229

    The Martyrdoms of Socrates and of Christ                        230

    Outline of the Conclusions arrived at                           233


    PART III. ART


    CHAPTER X

    Art and Life

    Tolstoy’s Account of the Nature of Art                          236

    Of the Standard of Art                                          241

    Of the Purpose of Art                                           241

    Criticism of his Conclusions                                    245

    Art, Man’s expression of Life                                   246

    Art and Beauty                                                  251

    Order and Change as Principles of Life and Art                  253

    Classification of the Arts                                      254

    Examples of the Presentative Arts—(_a_) Architecture            256

      (_b_) Ornament                                                259

      (_c_) Music                                                   261

    The Representative Arts—(_a_) The Plastic Arts                  265

      (_b_) Dancing                                                 270

    The Evocative Art: Literature                                   271

    The Union of Music and Poetry                                   272

    Conclusion                                                      273


    APPENDIX A

    _Sum ergo Cogito_                                               275


    APPENDIX B

    Co-operation and Competition                                    279


    APPENDIX C

    Is Life worth Living?                                           282


    APPENDIX D

    St. Francis the Poet                                            285


    APPENDIX E

    Isabella and Claudio                                            288


    Index                                                           295




PARALLEL PATHS




PART I: BIOLOGY




CHAPTER I

THE ARGUMENT FROM DESIGN

    “The wisdom of the divine rule is apparent not in the perfection
       but in the improvement of the world.”—Lord Acton.


Paley’s Natural Theology though not by any means an epoch-making
may perhaps be called an epoch-marking book. It was the crown of
the endeavour of eighteenth-century religious philosophy to found a
theology on the evidences of external nature. According to such exact
knowledge of Nature’s operations as was then generally available,
Paley’s attempt might well be thought to have succeeded. He opens his
argument with a striking and effective illustration. He imagines a
wayfarer crossing a heath who strikes his foot against a stone, and who
asks himself how it came into being. Paley thinks he might be content
with vaguely supposing that it was there ‘always.’ But suppose that
what he had found at his foot was not a stone but a watch and that he
now saw such an instrument for the first time. He would then certainly
have not been so easily contented with an answer to the riddle of
its existence. He would, if he examined it minutely, have observed
that it was a structure intended for a certain purpose, and having
all its parts arranged for that object, and mutually interdependent
The different substances of which it was composed would be discovered
to have each its special appropriateness for the fulfilling of some
particular function in the economy of the whole. Though unacquainted
with watches he would, if he was a man of sense and cultivation,
infallibly conclude that he had before him an instrument intelligently
constructed with a certain object in view—the object of measuring the
flight of time. He would feel assured of this, even though he should
find that the object of the mechanism were not attained with absolute
accuracy, and even though there were some parts of it whose functions
were not clear to him. The watch would be rightly regarded as a work of
design; and the observer would be justified in arguing from it to the
existence of a designer, endowed with the faculties of intelligence and
conscious purpose, by whom the watch must have been put together.

The rest of Paley’s Natural Theology is an application of this analogy
to the question of the origin of the universe. Ranging over the whole
field of animate and inanimate nature he points to instance after
instance of what appears to be the minute and thoughtful adaptation
of means to ends, the co-ordination of part with part in the interest
of the whole, and he has no difficulty, from this point of view,
in showing the world of nature to be a piece of mechanism far more
wonderfully and ingeniously constructed than any watch, and bearing
_prima facie_ evidence of the most convincing kind of its construction
by a Being possessed of intelligence, purpose and foresight precisely
resembling those attributes as displayed by man, but vastly heightened
and enlarged. As the watch must have been made by man, so a manlike
being, endowed with the necessary powers and faculties, must be
postulated as the maker of the material universe. And thus the
existence of a God made in the image of man appeared to have been
demonstrated to the satisfaction of eighteenth-century theology.

But minds of real philosophic depth have always shrunk from pressing
home deductions of this sort. They have felt that the matter is
probably not quite so simple as it might appear on the surface, and
they have recognised that if one is allowed to argue from the phenomena
of nature to the qualities of the author of nature one cannot draw an
arbitrary line including only those facts which testify to wisdom,
power and goodness, and excluding from view all those which reveal
imperfection of design and execution, or which would convict a man, if
he were their author, of inhumanity and injustice. If the universe is
really analogous to a watch one is entitled to examine it throughout
as one would examine a watch. All watches testify to intelligence and
design, but besides good watches there are bad ones, there are those
which are made of cheap materials, rudely put together, with showy
exteriors and unreliable works. Every watch, if examined by experts in
mechanism, in art, and so forth, would reveal the characteristics of
its designer and maker, and these characteristics would not always be
admirable. They would rarely, in fact, be altogether admirable. If we
apply these methods of inquiry to a universe which contains malarial
mosquitoes, slave-making ants, snakes, earthquakes, and all the pests
which blight and deform life without calling forth any strong or noble
qualities to carry on the contest with them, we shall go where Paley
certainly never intended to lead us, but we shall go there by Paley’s
road. The fact is that these methods are altogether fantastic and
inapplicable. The universe is not made like a watch. When we observe a
human being or one of the higher animals we say, ‘He has such and such
qualities; he is faithful, false, brave, cowardly, diligent, indolent,
strong, weak, beautiful or ugly,’ but we do not think of referring
his qualities back to certain attributes of an unknown maker of his
physical and mental organism. A philosophy worthy of the name has
always tended to regard the world as in some sense a vital organism,
and has asked ‘What is it?’ rather than ‘What does it prove about some
other being?’ “How green must be the maker of all grass” was quite
a legitimate satire on all such attempts to deduce the qualities of
a hypothetical creator from the phenomena of the universe. Thus the
mistake of Paley and his school was fundamental. It was the mistake of
seeking God in fragmentary phenomena—the same mistake, essentially, as
that rebuked by Christ, by which every calamity or material blessing
is regarded as a ‘judgment’ or a reward. His method, if applied with
thorough-going consistency, destroys its own basis, for the One and
the Many, the Whole and the Parts, cannot be apprehended at one and
the same time by one and the same faculty of any human mind. Looking
at phenomena alone, and thinking in that sphere, we cannot say that
God made the world but rather that the world is becoming divine.
Philosophically and religiously, God is all in all—historically, He is
not the beginning, He is rather the end, the end in which the whole
history is resumed.


Paley’s elaborate argument was felt by the orthodox of his time to be
called for, even though at this period his way of thinking was popular.
The conception of the world as a vital organism was as yet, indeed,
very vague, and unsupported by any detailed, scientific scrutiny of the
facts of nature, but it was in the air—it had always been in the air;
it always held the minds of cautious students back from a complete
surrender to the facile but illusory way of thinking typified by
Paley’s famous analogy of the universe and the watch. Bacon knew that
species could be transformed by the action of a new environment.[4]
Goethe had a clear conception of the evolution theory, based on a study
of organic structure. Erasmus Darwin, in 1794, had uttered the great
and final word: “The world has been generated rather than created.”[5]
Lamarck’s Philosophie Zoologique was not published till 1809, nine
years after Paley’s Natural Theology, but his conception of the
development of special characteristics by habitual exercise and their
transmission by inheritance had been freely mooted in Paley’s day, for
Paley frequently takes occasion to combat it. Even the conception of
natural selection as an agency in the formation of types of being may
be traced in a fantastic form as far back as to Empedocles,[6] while
Plato, or whoever composed a striking couplet attributed to him in the
Greek Anthology, had divined the plasticity of natural forms. “Time,”
he wrote, “sways the whole world; time has power in its prolonged
lapse to change the names and shapes, the nature and the destiny of
things.”[7]

Fifty years after the appearance of Paley’s work, the grandson of
Erasmus Darwin wrote ‘No thoroughfare’ on the entrance to Paley’s line
of speculation, and closed it to mankind for ever. He did this in two
ways—first by marshalling from his studies of comparative anatomy and
of embryology an extraordinary volume of convincing evidence for the
_fact_ of the mutability of natural forms, and secondly by his attempt
to establish a plausible _method_ by which the change and development
of organs and types might actually have taken place. The method, summed
up in the phrases ‘natural selection’ and ‘survival of the fittest,’
was what really caught the attention of the world, and gave his
doctrine the wings which carried it into almost every sphere of human
thought. However we take it, it was certainly an immense contribution
to the organization of knowledge, but whether it is really what it
first seemed to be, the basic fact at the bottom of all the phenomena
of evolution, is coming to look more and more doubtful in the light of
later researches.[8]

This question will have to be considered later on in the course of
this study, and in relation to its main inquiry, which is this: What
precisely was the change in philosophic and religious outlook brought
about by the full and final establishment of the doctrine of evolution?
Where has evolution left the argument from design? Must we study nature
as a mass of unrelated phenomena, or can we discern, through these, any
fundamental unity to which they stand in organic relation; and if we
can, what is the nature of this unity?


It will be useful in the first place to have before us a typical
specimen of Paley’s method. I shall choose as an example the case which
he considered so striking that he deemed it almost sufficient in itself
to bear the whole weight of his argument In his ninth chapter, ‘On the
Muscles,’ he writes:—

    “The next circumstance which I shall mention under this head of
    muscular arrangement is so decisive a mark of intention, that it
    always appeared to me to supersede, in some measure, the necessity
    of seeking for any other observation upon the subject; and that
    circumstance is, the tendons which pass from the leg to the foot
    being bound down by a ligament to the ankle. The foot is placed at
    a considerable angle with the leg. It is manifest, therefore, that
    flexible strings, passing along the interior of the angle, if left
    to themselves, would, when stretched, start from it. The obvious
    preventive is to tie them down. And this is done, in fact. Across
    the instep, or rather just above it, the anatomist finds a strong
    ligament, _under_ which the tendons pass to the foot. The effect of
    the ligament as a bandage can be made evident to the senses; for if
    it be cut, the tendons start up. The simplicity, yet the clearness
    of this contrivance, its exact resemblance to established resources
    of art, place it amongst the most indubitable manifestations of
    design with which we are acquainted.

    “There is also a further use to be made of the present example, and
    that is, as it precisely contradicts the opinion that the parts of
    animals may have been formed by what is called _appetency_, _i.e._
    endeavour perpetuated and imperceptibly working its effect through
    an incalculable series of generations. We have here no endeavour
    but the reverse of it—a constant renitency and reluctance. The
    endeavour is all the other way. The pressure of the ligament
    constrains the tendons; the tendons react upon the pressure of the
    ligament. It is impossible that the ligament should ever have been
    generated by the exercise of the tendon, or in the course of that
    exercise, forasmuch as the force of the tendon perpendicularly
    resists the fibre, which confines it, and is constantly
    endeavouring not to form, but to rupture and displace, the threads
    of which the ligament is composed.”

Paley’s account of the function of the annular ligament at the ankle is
correct, and strikingly put. A similar ligament occurs at the wrist,
and navvies who have hard muscular work to do in digging and shovelling
are wont to reinforce this ligament and to keep it from rupture by a
leather strap round the wrist. The strap performs exactly the same
function as the ligament, and from Paley’s point of view one is as
artificial, as much a ‘contrivance,’ as the other. But his point of
view is wrong. He conceives the Creator as having at his disposal
fully formed elements or materials—sinews, bones, ligaments, and the
like—and assembling them into a working mechanism. In fact, however,
none of these things is now what it was originally—time, as Plato says,
has changed its “name and shape.” The annular ligaments are recognized
by modern anatomists as having originated in special thickenings of
the fascial sheaths of the adjoining muscles of the wrist and ankle.
They had a function which was not originally connected with keeping
down the long tendons that run along the interior angle of the leg and
foot. Contractility, as biologists tell us, is a fundamental property
of living protoplasm; and it is easy to imagine that, at the very
beginning of the formation of muscular structure and bone articulation,
two lines of contractile force might cross each other and thus permit
the gradual evolution of the present arrangement, nature continually
visiting with disability and extinction those individuals in whom
the resisting power of the muscles which were eventually to form the
annular ligament was unduly feeble, and giving a better chance of life,
and of the propagation of their kind, to those in whom it was strong.
The instance, in fact, is one of those in which the explanation of
development by natural selection is most obvious and plausible.

In his second paragraph Paley touches on the theory of “appetency,” the
supposed tendency of natural structure to alter and adapt itself on the
lines indicated by the actual exercise of function, and in consequence
of that exercise. This is practically the theory since identified with
the name of Lamarck. Paley scarcely does it justice, for no Lamarckian
would suggest that a muscle could, in the course of its exercise,
develop the ligament whose function is to restrain it. The ligament
would be developed by its own exercise. But as Lamarckism will be
discussed later on, the issue as between these rival theories need not
be debated here.

Let us set beside Paley’s argument on the annular ligament of the
ankle a passage from a modern scientific work, Strasburger’s Text
Book of Botany. It will introduce us, from the side of the strictest
scientific observation and of the fullest acceptance of the evolution
theory, to the same kind of problems as those discussed in Paley’s
Natural Theology, and it will raise in a very distinct and unevadable
fashion the question, what we are to think of the power manifested in
the operations of Nature. In the introduction to his work, in which
Dr. Strasburger had associated with him three other eminent German
botanists, we find the following remarkable passage dealing with
circumstances observed to exist in the ‘phylogenetic’ or tribal (as
opposed to the ‘ontogenetic’ or individual) history of plant species:—

    “Although the great importance of natural selection in the
    development of the organic world has been fully recognised by
    most naturalists, the objection has been raised that it alone is
    not a sufficient explanation of all the different processes in
    the phylogeny of an organism. Attention has been called to such
    organs as would be incapable of exercising their function until
    in an advanced stage of development, and so could not originally
    have been of any advantage in a struggle for existence. How could
    natural selection tend to develop an organ which would be useless
    so long as it was still in a rudimentary condition? This objection
    has led to the supposition of an internal force residing in the
    substance of the organisms themselves and controlling their
    development in certain definite directions. Many naturalists indeed
    have gone so far as to affirm that only the less advantageous
    qualities have been affected by the struggle for existence, while
    the more advantageous have been uninfluenced by it”[9]

One can easily imagine what a modern Paley bent on reconciling
orthodoxy and evolution would say to this. He would cry, Design,
forethought, intelligence—here is the clearest evidence of it!
And indeed there are many modern biologists who do not shrink from
the admission that the processes of nature must ultimately be
interpreted in terms of will or intention, not in terms of chance or
blind mechanism. Thus, to the Darwinian argument that organs can be
and are, demonstrably, formed by gradual adaptation to surrounding
conditions without assuming the necessity of purposeful design, it
is often replied that the very fact of adaptability is itself one of
the strongest evidences if not of design at least of purpose. And J.
v. Uexküll, who describes life as consisting essentially in the fact
that it proceeds according to design (_planmässig_), has the following
remarkable passage in his Experimental Biology[10]:—

    “When we look backwards, every phase in the process of development
    seems to us to have proceeded in a strictly causal manner from
    physico-chemical processes. But when we turn to look forward, it
    is certain that the physico-chemical processes if left to their
    own causality must immediately bring about the destruction of the
    organism. In fact, the clearest definition we can give of dying
    is to say of an organism that its processes now go on no longer
    teleologically (_zweckmässig_) but only causally.”[11]

Yet the modern Paley would be rash in arguing from facts like these
(supposing them fully established) to the conscious, intelligent
contrivance of a single foreseeing Mind. For very few things in this
universe appear to be done as a presiding, conscious intelligence
would do them. Conscious intelligence would not have evolved the
giant armadillo only that the whole species might be destroyed by
the sabre-toothed tiger, and would not have armed the sabre-toothed
tiger for the attack on the armadillo in such a way that when he had
exterminated the victim-species the formation of his teeth rendered
it impossible for him to prey on any other animal.[12] Conscious
intelligence would not have allowed the relic of a disused organ, in
the shape of the vermiform appendix, to be a constant source of danger
and suffering to countless generations of men—danger against which no
exercise of prudence or energy can secure them.

Let us examine a couple of other crucial cases. The embryo of every
mammalian animal is prepared in the womb for the life it is to live
under wholly different conditions. Lungs are formed when there is no
air for them to breathe, eyes when there is no light, a digestive
system when nourishment is derived as yet direct from the mother’s
blood. This capacity for anticipatory development during a period
of gestation or incubation becomes absolutely necessary for the
maintenance of life as soon as animals, ceasing to multiply by merely
dividing in two, become more highly organized and have to devote
special germ-cells to reproductive purposes. Here is certainly purpose,
or, as I should prefer to call it, _directivity_—here we recognize
what Reinke calls the X-factor in nature. But conscious, intelligent
contrivance? We must recollect how many of these embryos are destined
to perish at birth or before attaining any appreciable degree of
independent life. Would not intelligence foresee that, and bring to
birth only what was destined to endure?

Again, there are certain species of butterflies which have put
on a coloration and a form the effect of which is to aid them in
evading the attacks of birds. They were not created so; they have
become so; and the precise manner of the becoming will be fully
discussed in a later chapter. Let us assume for the moment that this
adaptation did not occur by a series of lucky accidents or by any
merely mechanical process. Are we, then, bound to attribute it to
intelligent contrivance? The question will be best answered by simply
putting a case which admits of no doubt. Suppose there were an island
in which there were no birds, except such as prey on fishes or on
each other, but never on insects. The butterflies on this island, if
there were any, would certainly show no trace of protective form or
coloration. But at some time or other insect-eating birds might be
introduced to the island, as the English sparrow has been introduced
in Australia. Then, if the extermination of the butterflies did not
proceed too rapidly, we might expect, in the course of generations, to
see protective adaptations assumed. But could we expect to see them
assumed _in anticipation_ of the advent of the destroyers? We could
not. Naturalists, however much they may differ, as they do differ, upon
the question as to how protective adaptations actually take place,
would all agree that they could not possibly take place in anticipation
of needs not yet present. If they did, we should have a miracle, and
where miracle comes in knowledge goes out. The cases where conscious,
intelligent contrivance would be unmistakably recognizable are just the
cases which never occur. The signal service rendered by the champions
of the evolution theory,

    Quos nec fama Deûm, nec fulmina, nec minitanti
    Murmure compressit Cœlum,

is that they conquered the realm of organic nature for true knowledge,
and gave the drama of its development a new and profound interest,
by showing with an uncompromising courage only equalled by the
extraordinarily minute and patient research which justified it, that
the _apparent_ instances of divine contrivance with which nature teems
must be explained by the responsiveness, the adaptability, of living
protoplasm. Needless to say, this demonstration does not in the least
_disprove_ the existence of God as a supreme, conscious, personal
Intelligence.[13] But it does forbid us to deduce the existence of such
a Being from the observation of natural phenomena. A living, developing
universe has been set in the place of a Divine Mechanician operating on
dead matter.


The question, what conception we are to form of the forces of
evolution, will be more fully discussed in the succeeding chapters on
Biology, as a foundation for views which will afterwards be put forward
in relation to Ethics and to Art.

But first we must clear the ground a little by considering what it
really is that we are to study, and if it be possible to study it at
all. Nature-study if it is to be possible must begin, and if it is to
be fruitful must end, in something which is not strictly the study of
nature, but which we call Philosophy.

One of the most brilliant examples of that union of philosophic
speculation with nature-study which is so marked a feature of the
German thought of our day is H. von Keyserling’s work, The Structure of
the World.[14] Keyserling begins by laying it down as a postulate of
thinking that “The Universe is a rounded, inwardly coherent Whole.”

A postulate of thinking this is indeed, and more than that—it
is a postulate of living. If under all the variety and apparent
discontinuity of the universe there does not lie _One_ all-pervading
and unifying Power, then meditation and action are alike vain, for none
can tell the hour when some incursion of the unknown may not shatter
our cosmos into chaos, or leave us in a new universe with the edifice
of our past experience, the familiar home of the spirit, lying in ruins
around us. Every one assumes, consciously or unconsciously, that there
is such a Power, that the universe is One, that however mysterious,
however little known or understood it may be, it is not essentially
deceptive or incalculable. The savage and the philosopher alike assume
this, and act upon the assumption. It is perhaps possible not merely
to assume but to prove it. For let us try to imagine what would be the
case if it were not true. If the Principle, the ultimate Reality of the
universe, be not one it must be at least dual. There must be not less
than two principles. Now there are only three ways in which these two
principles—and what we say will hold good for any greater number—can
be related to each other. They must either (1) be identical, or (2)
they must be complementary, each possessing something which the other
is lacking in, or (3) they must negate each other and be mutually
contradictory and exclusive. But two absolutely identical principles,
if we can conceive such a thing, are indistinguishable from one. Two
or more complementary principles, again, make up, when taken together,
but a single whole, as in the Christian Trinity. Therefore if the
universe be really dual, its two principles must negate and contradict
each other. Now these two hostile principles must either be equal
in force or one must be more powerful than the other. In the latter
event, seeing that they divide between them the sum total of existence
and thus stand in naked and essential antagonism, with no place for
evasion, and no auxiliary or modifying forces to call in, it follows
of necessity that if one surpassed the other by even the smallest
conceivable excess, it must, in eternity, master it and reduce it to
impotence. So by this road we come back to unity again. If, however, we
suppose our two forces to be co-equal and co-eternal, we have to ask
ourselves what we mean by supposing them to be antagonistic. Antagonism
can only arise when there is action. But two equal forces acting in
direct contradiction to each other must mutually cancel each other, and
the result is zero. On such an hypothesis the universe could never have
come into being. It may also be pointed out that the hypothesis itself
seems to be irrational. For action means the production of a change of
some kind, change in the nature or situation of objects. But if one
of our forces is producing changes of a certain kind and the other
producing changes of another kind, then they are not contradictory
but complementary. The only real antagonism between two ultimate
principles must consist in one of them being identified with action,
change, life, the other with immobility and death. But a principle of
immobility and death, if there could be such a thing, could not also be
a principle of action, not even of destructive action, for to act at
all would be a contradiction of its own nature. It would begin and end
in total _in_action, and the field would be clear for the other Power,
just as if nothing else existed. It follows that, in the living and
moving universe around us, there cannot be any such thing as an active
principle of destruction and death. We are obliged to perceive Being
under the guise of Becoming and Becoming under the guise of Change and
Progression. This is a process taking place in the visible and temporal
order of things and capable, under certain conditions, of partial
arrest or retrogression. But the Whole, regarded as a whole, can be
and can contain nothing but life, and must under all its diversity
(which is an aspect of life) be One. It is this unity which alone can
make intelligible and rational the diversity of which every study of
life must treat. It is my endeavour in the present work to bring into
clear light some important aspects of this unity, as revealed in the
inter-relations of the parts of which, to our eyes, it seems to be
composed.[15]




CHAPTER II

THE WHEEL OF LIFE

    I heard them in their sadness say
    The earth rebukes the thought of God;
    We are but embers wrapped in clay,
    A little nobler than the sod.

    But I have touched the lips of clay;
    Mother, thy rudest sod to me
    Is thrilled with fire of hidden day,
    And haunted by all mystery.—A.E.


It has long been known that no definite line of demarcation can be
drawn between the animal and the vegetable worlds. There are lowly
organisms which cannot be decisively referred either to the one or
to the other. It has been more recently shown that the apparently
more strongly marked line between the living and the non-living also
grows wavering and indistinct in places. Metals are known to respond
to stimuli and to show ‘fatigue’ in a manner commonly attributed only
to the nervous system of animals,[16] while some of the phenomena of
crystallization strongly resemble those of vitality.[17] Le Dantec has
uttered the latest word of physics on this subject, where he insists on
the “absence of all essential difference and all absolute discontinuity
between living and non-living matter.”[18] Indeed, one may say of
nature-study in general, that if, as Plato said, the beginning of
knowledge is in definitions and classification, the end of it lies in
getting rid of them. There is probably no such thing as a universally
applicable definition of any group of natural phenomena. _There is
certainly no condition of matter of which we are entitled to say that
Life is impossible without it._ Still, natural groups have well-marked
central features, even if at their margins they melt into something
else. Now the things which in the ordinary sense of the word we call
Living are marked by these characters: Their chemical constituents
are always compounds of carbon. These compounds are what is called
‘unstable’—they ‘consume’ or disintegrate by combining with oxygen in
air or water. In this process organisms obtain the energy necessary
for assimilation and growth. The above characters (carbon-compounds,
chemical instability, and faculty of assimilation) apply to plants and
animals alike. But we find, in general, that plants are able, from
inorganic mineral constituents such as carbonic acid, water, nitrates,
sulphates, etc.,[19] to build up the organic compounds like proteid,
albumin, the carbohydrates, alcohol, fat; while animals use for their
nourishment not the inorganic substances but only organic compounds
already formed by plants or by other animals. A well-developed
vegetable world must therefore, it would seem, have preceded the
appearance of animal life on the globe.[20] It was long believed that
these organic compounds of carbon could only be formed by the vital
action of living vegetation. One of the epochs in the history of modern
chemistry has been the demonstration (first by Wöhler, in 1828,) that
many of them can be produced in the laboratory from inorganic chemical
constituents. But this is only effected by circuitous and difficult
ways, and—a circumstance often overlooked—it only resembles what is
accomplished in nature if we include under nature the directive agency
represented by the chemist himself, as well as the materials with which
he deals.

The characteristic colour of living vegetation is green. This is also
the rarest of colours among the higher animals.[21] It is due in
vegetables to the presence in their cells of grains of the substance
known as chlorophyll, which very few animals possess or have need
of. It is developed normally under the action of sunlight, and plays
a most important part in the economy of the plant. The usual method
by which any organism obtains the energy necessary for its vital
functions is through the oxidization, _i.e._ the slow burning, of its
substance, by combination with the oxygen of the air. The process is
to all intents the same as the more rapid oxidization, under great
heat, of coal in a steam-engine. If a plant can obtain sugar, which
oxidizes easily in contact with atmospheric oxygen, it has thus a fund
of energy to draw on for all the processes of its life. Now sugar is
composed of carbon and water. Carbon exists in the air, in combination
with oxygen, in the form known as carbonic acid. Chlorophyll, in some
way as yet unexplained, enables plants, when acted upon by light, to
take in carbonic acid from the air and to disintegrate it into its
constituents, carbon and oxygen. The oxygen disappears again in the
air, and the released carbon combines with water in the plant to form
sugar,[22] thus giving the plant its needed store of potential energy.
All it does with this energy is to live, grow, and reproduce its kind;
till at length a time comes when the assimilative energy weakens
relatively to the forces of decay, and the plant dies; it is again
resolved into the chemical constituents from which it was built up;
but not without having passed on the flame of life to burn afresh in
its descendants.

Plants which have no chlorophyll, like certain bacteria and moulds, and
which, therefore, cannot decompose the carbonic acid in the air for
their nourishment, offer an interesting example of the manner in which
Nature contrives to get her way, if not by the normal instruments, then
by the utilization of others. They acquire their first store of energy
sometimes like animals, from other organic compounds, or they take
carbon from acetates and tartrates. The nitro-bacteria appear to depend
on ammonia derived from decaying animal matter, and the moulds draw
their energy from sugar, which (as in our jams, etc.) they find already
formed.

There are other plants, such as the fly-eating _Drosera_, which feed
upon organic substances with the aid of digestive juices, exactly as
animals do; and there are animals, such as _Hydra_ and others, of very
primitive form,[23] which produce chlorophyll and are thereby enabled,
like plants, to feed upon carbonic acid. The distinction therefore
which has been drawn between the two kingdoms as regards their modes of
nourishment must, like other definitions of natural groups, be taken
to apply to central and typical forms and not to constitute a distinct
boundary line. Allowing for these exceptional cases, we may say
broadly that the wheel of life makes its full circle in passing from
inorganic matter through plants to animals and thence back to gases and
minerals again. The process of taking in fresh matter, transforming it
chemically into living tissue, and thus repairing the waste occasioned
by the decomposition of the carbon-compounds of that tissue, is
technically known as Metabolism. This is the typical and characteristic
function of organic life.

Now this function of living matter, or Protoplasm, depends upon two
elements: first, its Substance; secondly, its Structure. As regards
the former, we are in this serious difficulty, that living matter can
never be chemically investigated by any means at present known, for
it dies immediately in presence of any of the reagents which are used
to ascertain its chemical composition. It is known that there are no
_elementary_ substances in living matter which are not also found
in the world of inorganic matter, but it is also known that their
synthetic combination in living is different from that which obtains in
dead tissue,[24] and it is precisely through this factor—that of the
grouping or synthesis of elements—that the most remarkable forms of
energy are developed.

The secret of life, therefore, cannot be stated in terms of chemistry,
because we cannot surprise the secret of its chemical synthesis. Even
if we could do this we should still be unable to say why certain
syntheses should appear in living matter and resolve themselves into
others at death.

We find, however, in the investigation of organic tissue (plant or
animal) by such means as are available, that one substance is common
to all the organic and is never found (as such) in the inorganic
world. This is called Proteid. It is composed of five elements—Carbon,
Hydrogen, Sulphur, Nitrogen, and Oxygen, which are combined in
proportions not at present ascertained. Subject to the limitations just
set forth we may say that proteid is the essential stuff of organic
tissue. The two other usual (though not, like proteid, universal)
constituents of this tissue—the Carbohydrates (sugar, starch, etc.) and
the Fats—are, it is believed, formed partly from the products of the
metabolism of proteid.

When we come to deal with the essential Structure of life we are
in much the same difficulty as that in which we found ourselves in
investigating its chemical Substance. We can observe living cells under
the microscope, but the most powerful microscope has never reached
the limits beyond which we can say that there is no structure. There
is another limitation too. The microscope has revealed the fact that
all living tissue is made up of cells, but the internal structure of
the cell, beyond the fact that it is composed of a fluid substance
within which a darker coloured nucleus is usually embedded, could not
be ascertained until the recent device of staining the object with
aniline dyes had been thought of. Different substances in the cell are
found to take these dyes differently, and thus a world of structure
of the most singular kind has been revealed in what formerly seemed a
simple, semi-transparent fluid. Some parts of this structure hover, as
it were, upon the very edge of perceptibility, the most suitable dyes
for bringing them under observation not having been as yet discovered.
There may be others which no dye can reveal, but which are yet active
and necessary parts of the organism. Moreover, here too the cell is
killed by the means taken to observe it, and the processes in which its
structure is engaged can only as a rule be deduced from the observation
of a great number of cells in which their internal movements are
arrested at different stages of completion.

It has been practically demonstrated that all organic life must
be at least duplex if not multiplex in its constituent elements.
In its simplest known form it consists of Protoplasm and Nucleus.
We know that the carrying-on of all vital functions depends on
peculiar relations existing between these two elements, but what
these relations exactly are is still quite obscure. Both protoplasm
and nucleus are compounds of proteid with other chemical substances
not yet fully determined. Protoplasm is a fluid, and has been shown
by the epoch-making observations of Bütschli[25] to have a structure
resembling that of an exceedingly minute foam. The nucleus usually
exists in the form of a single definite body, but it may be scattered
through the protoplasm of the organism in little granules. In the
lowliest of organisms, the _Amœbæ_, we have simply a speck of
protoplasm containing a nucleus, but with no surrounding wall of the
harder substance which protoplasm builds up for itself in the cells
belonging to higher forms of life. Such amœboid forms are the white
corpuscles in the human blood, whose slow changes of form we can
observe under the microscope, and which play so important a part in our
economy by feeding on the noxious bacteria which produce the various
forms of blood-poisoning and zymotic disease.

A more detailed account of the functions and structure of the cell must
be reserved for the next chapter. In considering these and all other
phenomena of vitality let me again recall the warning expressed in the
taunt of Mephistopheles to the young student: the lines are as true
to-day as they were when Goethe wrote them over a hundred years ago:—

    “If some living thing you would learn about,
    You begin by driving its Spirit out;
    There lie the parts of it, one by one,
    But the binding Spirit, alas, is gone!”




CHAPTER III

DE MINIMIS

    Immense have been the preparations for me,
    Faithful and friendly the arms that have help’d me.
       *       *       *       *       *
    “Before I was born out of my mother generations guided me,
    My embryo has never been torpid, nothing could overlay it.”

                                                Walt Whitman.


There are two functions of organic life which are often confused
together, but which it is well to keep distinct in our thought. These
are Growth and Development. The mark of growth is that an organism, by
assimilation from the outside world, becomes _larger than it was_. But
in development it becomes _different from what it was_. The history of
an embryo in the womb presents a succession of phenomena which, when
one comes to realize them, almost stagger thought; for, while remaining
the _same thing_ all through, it is continually becoming a _different
class of thing_—first two cells, then one cell, then a fish, a
quadruped, ultimately a human being. This is Development. Once born, it
is laid hold of by the principle of Growth which lasts until maturity.
Now in the groups called Species, as well as in individuals, we observe
exactly the same distinction. The members of a species multiply and
increase their numbers. This is Growth. But under certain conditions,
which we have now to investigate, they vary in type and ultimately give
rise to new species differing widely from that from which they sprang.
This we call Development or, in the more popular term for the process
when applied to species, Evolution.

The investigation of this process in all its details has been the
master-impulse of biology ever since the fact of the process was
established by the researches of Darwin.

In Darwin’s time the study of evolution was mainly an affair of
what is called Natural History But it has now been realized that
fully to comprehend the processes involved—so far as they can
ever be comprehended—it is necessary to find out of what kind of
material living beings are composed, and how their fundamental
processes take place. “The ultimate problems of sex, fertilization,
inheritance, and development,” says Wilson, have been now “shown to be
_cell-problems_.”[26] Before going further, therefore, we must give
some account of the leading facts connected with the structure and
vital action of the cell.


Since the publication of the Origin of Species, probably the most
important contribution to biological theory is to be found in the
researches of Dr. A. Weismann, and particularly in his large work, The
Evolution Theory, of which a masterly English translation has recently
appeared.[27] Weismann, on one side, represents an heroic attempt to
bring back to the strictly mechanical principles of Darwinism the tide
of biological speculation, which has been flowing more and more in
the direction of recognizing an essential and not a merely fortuitous
connexion between the goal of the evolution of natural forms and the
means taken by nature to attain it. On another side he has brought the
physiology of the cell into true relation with the natural history of
the organism and of the species, and has become the author, or at least
the first great expounder and systematizer, of a theory of heredity—the
now famous Germ-Plasm theory—much of which seems a solid, permanent,
and deeply important contribution to knowledge. But this theory seems
to lead straight to a non-mechanical or psychic conception of the
driving-force of evolution, and Weismann has therefore supplied the
other part which, in the view of the present writer and of many others
better qualified to judge, seems to be of the nature of a baseless and
improbable hypothesis, devised to find a means of avoiding recourse to
any non-mechanical conception of the ultimate nature of evolutionary
processes.

As we shall be much concerned with Weismann’s views, let us place at
the head of our study of them a couple of passages in which his general
attitude towards the phenomena of vital processes is expressed.

“In our time,” he writes, “the great riddle has been solved—the riddle
of the origin of what is best suited to its purpose without the
co-operation of purposive forces.”[28] “We must certainly assume,” he
declares, “that the mechanical theory of life is correct.”[29]

A longer passage shows us what he understands by ‘mechanical’:—

    “The living machine differs essentially from other machines in the
    fact that it constructs itself; it arises by development from a
    cell, by going through numerous stages of development, but none of
    these stages is a dead thing, each in itself is a living organism
    whose chief function is to give rise to the next stage. Thus
    each stage of the development may be compared to a machine whose
    function consists in producing a similar but more complex machine.
    Each stage is thus composed, just like the complete organism, of
    a number of such ‘constellations’ of elementary substances and
    elementary forces, whose number in the beginnings is relatively
    small, but increases rapidly with each new stage.”[30]

It would have been simpler, but it would not have suited Weismann’s
conception of nature, to say that the “living machine” differs
essentially from other machines in not being a machine at all, or
anything in the least like one. No machine constructs itself. No
machine can do anything but repeat a certain series of movements, each
series exactly similar to the last. What Weismann has described is
_not_ a machine, just because it is a living organism. It is surely as
true in biology as it is in mechanics that in any purely physical chain
of sequences you cannot by any possibility get more out at the end than
you put in at the beginning, unless you take it in upon the way.

“Development,” writes Weismann, “is an expression of life.”[31] But
“life,” again, is merely “a chemico-physical phenomenon.”[32] To say
that development is an expression of a chemico-physical phenomenon does
not seem a very illuminating or helpful generalization. The fact is
that the statement that life is a chemico-physical phenomenon does not
take us further towards an understanding of the subject than when we
say, what is equally true, that chemical and physical phenomena are a
manifestation of life. Life is everywhere. We use it as a convenient
term for the energies associated with ‘living’ protoplasm, because
we observe that when it is present protoplasmic structures act and
react (as in the phenomena of nutrition, for instance) in certain
chemico-physical ways, while, if it be absent, the same protoplasm
acts in other ways, also chemico-physical, but quite different from
the former, and analogous to the ways of minerals and of gases into
which dead protoplasm finally resolves itself. The chemico-physical
actions and reactions appear in a living plant or animal to be under
the direction of a force devoted to the preservation of that particular
organism. The smallest atom of organic life includes not only a
chemical compound but a chemist. In the mineral world we may say
broadly that there is no individuality of parts.[33] With protoplasmic
structure, therefore, a stage is reached in the evolution of life which
we may rightfully call ‘life’ _par excellence_, but there has been no
breach of continuity, and it is highly probable, as Weismann himself
suggests, that far below the limits of microscopic observation the
transformation of ‘dead’ into ‘living’ matter is continually going
forward. When, therefore, we speak of the action of living protoplasm
the distinction is rather between this action and that of a piece of
mechanism than between protoplasm and minerals or gases.

The phenomena of cell-growth, reproduction, and heredity are those
which lie at the basis of all organized protoplasmic life, and in
all the forms of that life, vegetable as well as animal, they are
extraordinarily similar; there is, in fact, nothing which all the
species of living things have so much in common. One of the most
wonderful and fascinating chapters in the whole range of science is
that which contains the account of these processes, and it is only
within the last few years that it has been possible to write it.
Weismann, in a certain section of his Evolution Theory, has brought the
facts together in a manner which, for its lucidity and mastery of the
subject-matter, deserves to be called a classic example of scientific
exposition.[34] To understand the basis of the higher manifestations
of life, these processes, as we have said, must first be understood,
and an account of them, based on Weismann, and accepting his germ-plasm
theory so far as it seems to accord with established facts, will be
given, of course only in the broadest outlines.[35] At the same time
it will be attempted, here and there, to throw some light on the
_rationale_ of the processes described.


All animal and vegetable structure arises from cellular tissue, and in
fact _is_ either cellular tissue or, as in the case of bones, scales,
etc., the mineral deposit formed by the action of cells. The simplest
living forms are composed of single cells, and the most complex and
huge of them were each once nothing more than a single cell, possessed
of the powers of development and growth. In multicellular organisms,
this single originating cell is usually formed by the fusion of two
imperfect cells by what is indifferently called conjugation, sexual
reproduction, or ‘amphimixis.’ All cells, whether they are the product
of conjugation or not, grow, when they do grow, fundamentally in the
same way, and this way must now be described.

The contents of the typical cell are broadly differentiated into (1)
a more or less hardened envelope containing (2) a substance called
cytoplasm (Gk. κύτος, a cell), and (3) a small, rounded, dark-coloured
body called the nucleus. Until recently nothing more than this was
known of the structure of the cell, and nothing at all of the functions
of the nucleus. Now, keener microscopic research and better instruments
have thrown a flood of light on cell-organization, and the nucleus
is revealed as a powerful factor in the vital processes of the cell
and the bearer of its hereditary substance[36]—that which makes it a
cell of some particular organism, plant or animal, and of no other.
This hereditary substance, divined by the botanist Nägeli, and since
observed by Weismann and others, is called ‘chromatin’ (from the fact
that it is observed by means of the stain it takes from the addition of
an aniline dye), or ‘idioplasm’ (Nägeli’s appellation), which might be
rendered the ‘selfhood substance’ of the cell.

Cellular structure begins, as has long been known, by the division
of a cell into two, each of the parts then proceeding to grow by the
assimilative power of protoplasm and in due time to divide in its
turn. A mass of these cells is called ‘cellular tissue.’ The so-called
‘budding’ of a small cell from the side of the parent is, of course,
simply a form of division. The process of division and redivision
goes on, accompanied by a differentiation in the shape and function
of the different cells or groups of cells which are formed, until the
structure of the plant or animal is completed. In these operations
the nucleus plays the principal part. The division of the cell is
essentially the division of the nucleus. A detached portion of a cell
which contains nothing of the nucleus can reproduce itself no more; it
perishes.

[Illustration: Fig. I.

This illustration, which (by permission of The Macmillan Co.) I take
from Wilson’s work, The Cell, is one of remarkable interest, for in it
the microscope has caught, in a piece of actual tissue from the skin
of the salamander, _Amblystoma_, three nuclei in different stages of
mitotic division. Most of the nuclei, which are seen as large, roundish
objects in their respective cells, show the chromatin in its ‘resting’
condition interspersed through the nucleus. The nucleus under _a_ shows
the chromatin gathered into chromosomes. At _b_ the centrosomes with
their astral figures (which can barely be detected) have been formed,
the chromosomes have carried out their longitudinal division, and are
being attracted half towards one centrosome and half towards the other.
A little above this the process has been carried further, and the sides
of the cell are beginning to contract, preparatory to forming two new
ones. In Fig. 2 will be found a clear representation of the astral
figures.

_To face p. 40._]


[Illustration: Fig. 2.

The above illustration from Wilson’s The Cell shows in more or
less diagrammatic form the stage of nuclear division in which the
chromosomes, as yet undivided, have arranged themselves in the centre
of the nucleus. The centrosomes with their astral figures have been
formed, and have taken their places near each pole of the nucleus. The
next stage is represented at _b_ in Fig. 1.]


When a cell is about to divide, an organ of recent discovery, termed
the ‘centrosome,’ comes into play. This appears as the core of a sort
of rayed or star-like figure, and it takes up its position beside the
nucleus. When the cell is resting, the chromatin is dispersed through
the nucleus in a mass of broken lines, forming a kind of network. When
division begins, this broken-up substance forms itself into a series of
small threads, sometimes straight, sometimes looped or curved. These
are called ‘chromosomes.’ There are always a definite and invariable
number of chromosomes for every species of plant or animal—the cell
of a man has so many,[37] of a grasshopper so many, of a lily so
many. The chromosomes range themselves in a belt across the centre of
the nucleus, and the centrosome breaks into two parts, which take up
a position one at each end of the nucleus. Regarding the nucleus as
a tiny globe, we may say that the chromosomes lie in the equatorial
plane, while the two parts of the centrosome move towards the North and
South Poles respectively.

The centrosomes, at the two poles of the nucleus, are surrounded each
with a halo of ray-like processes (the centrosphere), and on the sides
next each other these rays penetrate the nucleus and join, forming a
spindle-shaped figure with a centrosphere at each end. This spindle
figure appears to be the organ by which the division is accomplished,
for each of the chromosomes now splits itself in two longitudinally,
as one cleaves a log of wood, and one half passes over to each
centrosphere, thus making an exact division of the whole chromatin or
hereditary substance. An indentation now appears in the outer wall of
the cell and also in the nucleus—it deepens and deepens, and finally
two cells appear instead of one, each with a nucleus, a centrosome, and
a supply of chromatin, the latter now breaking up into its original
condition of diffusion through the nucleus. In multicellular organisms
the two new cells, of course, do not separate, but a wall is formed
between them. Some plant-cells contain several nuclei; in this case
division of the nucleus is not necessarily followed by that of the
cell.[38]

Throughout the processes of cell division it is apparent that the
utmost care is taken to ensure an exact partition of the chromatin
between the two new cells. This partition has to be qualitative as well
as quantitative; for one chromosome may, and no doubt does, differ in
function and influence from another, and has various elements within
itself. The _longitudinal_ division of each chromosome, in which
the elements are arranged like beads on a rosary, ensures that the
different elements of the whole hereditary substance shall appear in
each new cell in exactly the same relative proportion as in the parent
cell; just as if two persons had to divide between them a dozen apples
of different varieties, and secured perfect equality, not by taking
six apples each, but by dividing every apple in two. _This is the
fundamental cause of the fixity of species_, which means the production
of offspring having the same specific characteristics as their parents.
How, under these conditions, the _mutability_ of species is brought
about must be discussed later. It is first of all necessary to inquire
more closely into the composition of the chromatin, and to study the
special phenomena of cell-growth in connexion with conjugation, where
new and extraordinary features come to light.


A chromosome is not, or is not usually, a simple body. In all but the
very lowest organisms it is composed, as we have said, of a number
of elements. Each of these elements is styled a ‘determinant,’ and
it controls the form, colour, and function of some definite part of
the future plant or animal. Weismann believes the determinants to be
grouped into complex bodies called ‘ids,’ each id containing all the
determinants necessary for a whole being, and each chromosome being
composed of a number of ids. These ids are microscopically visible;
they form the beads on the rosary already referred to; but their
exact composition and potency are largely conjectural at present.
How far the subdivision of determinants may go, it is, of course,
impossible to ascertain. We cannot say, for instance, whether there
is a determinant for every hair of the head, or one for the hirsute
covering in general, or one for each of the different sections of the
scalp. But the division is very minute. Each of the ids may be a very
complex body, as we see by the manner in which, in some families,
small physical signs like a patch of hair differing from the colour of
the rest, or a tiny pit or mole on the skin of a certain part of the
body, may be handed down, in that precise position, for generations.
There may be, and, in fact, in the higher plants and animals there
_must_ be, a number of determinants for each part of the structure,
and the final characteristics of that part must be the resultant of
a blend of all these determinants, the more powerful predominating
in proportion to their vitality and force. The whole body of the
chromosomes may therefore be said to represent one or more complete
beings in diagrammatic form, each part of the complete animal or plant
being represented by some part of a chromosome, though of course not
physically resembling it. And we thus strike on the very curious and
startling fact that, as far as we can see, _every_ cell in every
organism throughout the world of life contains all the elements of the
whole being to which it belongs, and is, potentially, that being.[39]
All the higher organisms possess two kinds of cells—reproductive cells
which have the faculty of fusing together to reproduce their kind,
and ‘somatic’ or body cells, which, although they all originate in a
reproductive cell, multiply only by division, and have the function of
forming the various parts of the bodily structure. Of the nucleus of a
germ cell “we cannot say that it differs in any essential or definite
way from the nucleus of any other cell.”[40] All possess the chromatin
or hereditary substance of the organism, though, according to Boveri,
the germ cells alone receive _all_ the chromatin of the parent cell,
the derived somatic cells having to part with some of it.[41] There may
be some distinction, though on what it may be based it is at present
impossible to say, between cells that are capable of developing into a
complete organized creature and those that are not.

Every somatic cell is doomed to perish, but every reproductive cell
now upon the globe is united, not metaphorically, not by a chain
of successive originations or impulses, but by actual identity of
substance, with the first beginnings of protoplasmic life in the abyss
of time; and it has before it a potential immortality commensurate with
life itself. It is not, as used to be thought, a physiological product
of the organism in which it dwells; it is a part of the original
reproductive cell from which that organism sprang.

To understand these conceptions we must now study the phenomena of
reproduction in the light of recent discoveries.


The lowest form of the reproductive process is, of course, by simple
division and redivision. This is characteristic of many of those
organisms which consist only of a single cell, and it may co-exist,
even in these, with a considerable degree of structural complexity,
as in the ‘trumpet animalcule,’ _Stentor raselii_. But among the
lowest of these unicellular organisms a curious process is sometimes
observed to take place, in which we may doubtless recognize the origin
of sexual reproduction. Two, three, or more _Amœbæ_[42] approach
each other, partially coalesce, and remain united for some time. They
then separate again. No new creatures are formed by this contact;
there are no visible results at all. But that _something_ which is
for the advantage of the organisms takes place during this period of
union is certain, and in the light of what is known of processes in
other organisms we can make a very good guess at what this something
is. Each _Amœba_ parts with some of its chromatin to some other and
receives an equivalent in exchange. The creature is thus reconstituted.
The element of _change_, which always provides so marked a stimulus
to vital processes, has been obtained. The process has actually been
observed in a certain Infusorian, _Noctiluca_. Two _Noctilucas_
coalesce, and then proceed to divide _at right angles to the plane of
contact_. This necessarily has the effect of giving to each of the
two new _Noctilucas_ which result from the division half the nucleus
and chromatin of one parent and half of the other. There is, however,
no actual new birth or multiplication of beings; there are only two
_Noctilucas_ as before.

We can now imagine that if a certain class of unicellular organisms
are in the habit of approaching each other for the purpose of this
interchange of portions of their chromatin, they might occasionally,
under the influence of the approaching conjugation, expel those
portions of chromatin _before_ another cell was in a position to
receive it. What would happen if two cells, each of which had thus got
rid of half its chromatin, were to come into contact? Plainly, they
would fuse together; they would not separate again; they would become a
new organism. Each would have supplied just what the other lacked.

This process, forming the bridge from mere cell division to sexual
reproduction, is a hypothetical one; it has not, I believe, been
actually observed in unicellular organisms, but it is exactly what we
find to be taking place when we reach the stage of sexual reproduction
among multicellulars. Multicellular organisms of more or less elaborate
structure plainly cannot, without breaking up, fuse together like
single cells. How, then, are they, as a species, to gain the advantages
of the temporary union and interchange of elements which we have
observed in the low unicellular organisms? Only in one way—by producing
special cells for this purpose. These cells must represent the whole
parent, they must be capable of shedding half their chromatin, and,
when they have fused, must be capable of growing into a complete
organism like the parent. When these specialized cells have been
formed, the others, the somatic cells, will at the same time have
been specialized for other functions, and will thus naturally lose
the original capacity for interchanging chromatin with other cells,
_i.e._ for conjugation. We see the significance, then, of Weismann’s
remark, “germ cells made their appearance along with the multicellular
body.”[43] They are an instance of that differentiation of structure
and function which takes place in all highly organized life. We
must note also that the benefits of conjugation which are realized
_individually_ by the lowest unicellular forms are only realized _as a
species_ by the multicellulars. A species must, then, be regarded as in
some sense an organic whole, and not as a mere aggregate of individuals.

In some very curious cases which stand on the borderland between
sexual and non-sexual reproduction, the same organism is capable of
employing both methods. Thus, among the lower seaweeds (_Algæ_), the
genus _Pandorina_ consists of a colony of sixteen green cells contained
in a kind of gelatinous matrix which the cells excrete. Each cell is
ordinarily capable of recreating the whole organism by division. But
after this process has gone on for some time, the need of conjugation
is felt, the colony breaks up and cells begin to fuse with each other,
though never with those of the same colony. In _Pandorina_ the two
conjugating cells are similar in appearance, but in the genus _Volvox_
we begin to see a difference in the appearance of the two kinds of
conjugating cells. What may be called the ‘female’ cells (germ cells)
are large and quiescent; the ‘male’ (sperm cells) are smaller and
active. The primary meaning of this is that the larger cells have
stored up a supply of nutriment for the young organism, and are
therefore bulkier and less active, while the others contain only the
bare elements of cell-structure and are therefore able, as they are
obliged, to be active in order to search out their quiescent mates.
A strictly vegetable organism, in this stage, may therefore possess
organs of locomotion, and be as free-moving as a fish. A remarkable
fact has come to light respecting those organisms (like some _Algæ_
among vegetables and Infusorians among animals), which are capable
both of conjugation and of reproduction by division, namely, that the
supply of nutriment often determines which method shall be followed.
If nutriment is abundant, division is practised; if it becomes
scanty, an impulse appears to be given to conjugation. Infusorians,
which ordinarily conjugate at pretty regular intervals, can be kept
indefinitely from doing so, and confined to division, by the simple
process of supplying abundance of nutritive matter in the water in
which they live.

    “As far as we can see from an a priori point of view,” writes
    Dr. E. B. Wilson in his great work on cell structure and cell
    phenomena, “there is no reason why, barring accident, cell-division
    should not follow cell-division in endless succession in the stream
    of life. It is possible, indeed probable, that such may be the
    fact in some of the lower and simpler forms of life where no form
    of sexual reproduction is known to occur. In the vast majority of
    living forms, however, the series of cell-divisions tends to run
    in cycles in each of which the energy of division gradually comes
    to an end and is only restored by an admixture of living matter
    derived from another cell. This operation, known as fertilization,
    or fecundation, is the essence of sexual reproduction, and in it we
    behold a process by which, on the one hand, the energy of division
    is restored, and by which, on the other hand, two independent lines
    of descent are blended into one. Why this dual process should take
    place we are as yet unable to say.”[44]

The actual mechanism of sexual reproduction is essentially the same
wherever it occurs, whether in a seaweed or a human being. Two cells
have to play their part in it, the Germ cell and the Sperm cell, and
these, in the higher orders of organized beings, come to be located
respectively in distinct classes or sexes of individuals. Reproduction
begins by the fusion of a sperm, or male cell with a germ, or female
cell.

These cells originally resemble the other cells of the same species,
containing the same number of chromosomes. If this number was, say,
sixteen, which is believed to be the number in man, then a fusion of
two complete cells, if it were possible, would produce a cell with
thirty-two chromosomes, and that would mean a different species of
animal. What happens is that each of the reproductive cells, male
and female, prepares itself for conjugation by getting rid of half
its chromosomes. Two divisions of the nucleus take place, _not_ as
in the ordinary fashion of cell-division, when the chromosomes split
longitudinally, but in such a way that, in each division, four of
the sixteen chromosomes are bodily expelled from the nucleus and
from the cell, when they either perish or, in some cases, appear to
help in forming an envelope of nutritive matter round the germ cell.
These divisions are called ‘maturation divisions,’ and until they
are accomplished, fecundation is impossible. When a sperm cell after
maturation comes into the neighbourhood of a germ cell, it penetrates
into its substance, using the long _flagellum_, or tail-like process,
with which it is equipped as an organ of locomotion. The two nuclei
come into contact and coalesce, and we have thus a new cell with its
sixteen chromosomes complete. This cell is the origin of the new being.
It divides in two, and each part divides and redivides, different cells
gradually differentiating themselves as muscular tissue, cartilage,
blood-corpuscles, nerves, reproductive cells, and so forth, until the
whole animal is built up and is ready for birth. One point of cardinal
importance must here be noted. The originating cell, as we have seen,
has eight of its sixteen chromosomes from one parent and eight from
another. When division takes place, these chromosomes, as we have seen,
split longitudinally, and the result is that each new cell gets exactly
the same mixture of chromatin as that of the originating cell—half
from each parent. This principle of division is carried on throughout
the whole process of building up the new being—every cell of the
latter, down to the minutest details of its structure, containing an
exactly equal quantity of hereditary elements from each of its parents.

It will be seen from the above account that the old conception of the
germ-cell as a passive body, incapable of a change till ‘fertilized’ by
a male or sperm cell, was altogether wrong. Both male and female cells
prepare themselves for conjugation long before it takes place, and
neither of them can be said to be a more active agent in fertilization
than the other. Not ‘fertilization’ but ‘fusion’ is the keyword of the
process. The mystical conception, as old as Plato, of the male and
female as representing respectively the two halves of a complete being,
turns out to be no poetic metaphor. As regards the essential features
of reproduction, it is a literal fact.

If we now ask why and by what mysterious law all these exact and
elaborate choric movements take place Weismann and his school refer us
to “chemotactic forces,” the nature of which is yet unknown. Chemotaxis
means simply the effect of the _presence_ of certain substances on
vital organisms without specific chemical action. The really essential
fact is that these special chemotactic forces are working _in living
protoplasm_. Life is not the product or the slave of any chemotactic
forces, but their maker and steersman.

The following passage from a work of the late Prof. Geo. Rolleston may
be pertinently quoted here:—

    “There exists, as is well known, a tendency to resolve all
    physiological into physico-chemical phenomena: undoubtedly many
    have been, and some more may still remain to be, so resolved; but
    the public may rest assured that in the kingdom of Biology no
    desire for a rectification of frontiers will ever be called out by
    any such attempts at, or successes in the way of, encroachment; and
    that where physics and chemistry can show that physico-chemical
    agencies are sufficient to account for the phenomena, there their
    claim upon the territory will be acceded to, as in the cases
    we have been glancing at [certain animal poisons], and where
    such claims cannot be established and fail to come up to the
    quantitative requirements of strict science, as in the cases of
    continuous and of discontinuous development or self-multiplication
    of a contagious germ, and in some others, they will be
    disallowed.”[45]

This was written in 1870. A generation later the attempt to reduce
life to a physico-chemical phenomenon had not made much way, as may
be judged by the following passage from Strasburger’s Text Book of
Botany:—[46]

    “Vital phenomena are essentially bound up with the living
    protoplasm. No other substance exhibits a similar series of
    remarkable and varied phenomena, such as we may compare with
    the attributes of life. As both physics and chemistry have been
    restricted to the investigation of lifeless bodies, any attempt to
    explain vital phenomena solely by chemical and physical laws could
    only be induced by a false conception of their real significance,
    and must lead to fruitless results. The physical attributes of
    air, water, and of the glasses and metals made use of in physical
    apparatus, can never explain qualities like nutrition, respiration,
    growth, irritability and reproduction.”

And Wilson concludes his work by the admission that

    “the study of the cell has on the whole seemed to widen rather than
    to narrow the enormous gap that separates even the lowest forms of
    life from the inorganic world.”[47]

“The lowest _observed_ forms of life” would have been a more exact way
of stating the fact.


Many questions of detail will occur to the reader at this point, which
he will find answered in the pages of Weismann or other investigators.
Here we must confine ourselves to what has a distinct bearing on the
objects of this study. One of the points which may be briefly touched
on is the question how it comes that two germ cells, once having
passed through their maturation divisions, cannot fuse and form a
new being; nor can two sperm cells. Were this possible we might have
‘self-fertilization,’ and virginal conception or parthenogenesis,
whenever two germ cells in the ovary of a female animal or in that of
a plant happened to come into contact. But since the object of fusion
is the union of (more or less) _unlike_, and not closely related,
elements, we find that even when a kind of self-fertilization occurs,
as in some plants, the sperm or pollen cells are differentiated
visibly, and probably still more invisibly, from the germ cells. But,
apart from this, the object of preventing the union of reproductive
cells of the same sex is mechanically attained by a very curious
device. The cell-organ by which division is carried out is the
centrosome. But in the course of the two maturation divisions of the
germ cell, that cell _loses its centrosome_, which seems to be absorbed
into the protoplasmic substance of the cell when once its task is
accomplished. No fusion of any number of such cells can therefore lead
to any further change or growth, for growth is based on cell division,
and the centrosome is the organ of division. The sperm cell, on the
other hand, does not lose its centrosome; it retains it to form the
organ of division for the new cell after conjugation. But, reduced
as it is to little more than a bare nucleus without any envelope of
nutritive matter, the sperm cell cannot support the intense vital
activity called for in the initial stages of the life of a new being,
and therefore sperm cells, like the germ cells, though for a different
reason, would be incapable of mutual conjugation, even if the element
of mutual attraction existed among them.

Another point of interest is the question of the determination of sex.
The known facts afford a strong corroboration of the general theory of
reproduction outlined above. It has not been ascertained, nor is it,
perhaps, ascertainable, whether the sperm cells of the male contain in
their chromatin a preponderance of male, while the germ cells provide
chiefly the female determinants.[48] However this may be, it is certain
that determinants which severally control the formation both of male
and of female structure are _always_ present in every combination of
the sperm and germ cells, those which exhibit the greatest energy and
vitality probably prevailing in the determination of the sex of the
future being. This accounts at once not only for the cases (rare in
the higher animals) of actual hermaphroditism, when the sex is really
indistinguishable, but for the universal occurrence in all male animals
of rudimentary female organs (such as mammæ) and in all females of
rudimentary male organs. Both sets of determinants are always present;
the more powerful prevail, but the weaker have a deflecting influence
on the total result. When the primary sexual characters of the embryo
are determined, they appear to communicate a stimulus which starts into
activity the appropriate secondary characters, such as colouring and
other modifications not directly sexual. An extraordinary case, which
I take from Beddard’s Animal Coloration,[49] is that of a chaffinch
which was found to have on the left side of its body the plumage of a
hen bird and on its right that of a cock. On dissection the meaning of
this freak of physiology was revealed. The bird was an hermaphrodite,
having the female organs of generation on the left side of its body and
the male on the right. Hermaphroditism is not in itself a very uncommon
phenomenon in birds (though here it is a monstrosity, not, as in slugs
and snails, a natural and useful condition); but the way in which in
this instance it governed the distribution of colour is most peculiar;
and of course it strongly reinforces Weismann’s conception of distinct
determinants for the various details of bodily structure.[50]

This brings us to the recognition of a _competition among determinants_
which is an important, indeed a cardinal, feature in Weismann’s theory
of evolution. He makes, as I am forced to believe, an illegitimate
and extravagant use of it, but the principle may really exist and
be operative without furnishing the master-word to the riddle of
organized being. The master-word, as I shall try to show, is nature’s
will to live. But before going fully into this argument, let us fix
in our minds the _rationale_ of those processes of elementary organic
life which have been described in this chapter. Protoplasmic life may
be supposed to have originated, and perhaps to be still originating,
in certain molecular combinations of matter. In other words, the
combination, when it took place, developed certain peculiar forces
through which it was enabled to maintain itself and to grow, by the
processes called assimilation and nutrition. These forces, then, were
potentially present in nature before the molecules combined to evoke
them. They are among the latent powers of life. They waited, ready
to be called into action when the required external form should be
arrived at in the play of molecular energy. Life first originated, no
doubt, in unconnected and inconceivably small units of protoplasm.
Between the units thus formed and their combination into the elaborate
structure which we now know a cell to be—packed as full of varied
energies, it has been said, as an ironclad is of machinery—there is
evidently a very wide gap. All we know is that when we have got the
cell, we find it in possession of a complex apparatus for subdivision,
which, taken together with the faculties of nutrition and growth,
enable any one cell to multiply indefinitely by producing replicas of
itself. To _life_ and _growth_, then, has been added the faculty for
_multiplication_. Here we strike on a veritable mystery. Why should
any new movement ever take place? Why should a cell ever divide in
two? We can only say that it is its property to do so.[51] It does
so because it is alive. Did this property first arise as one of a
multitude of aimless movements—the only one which ensured permanence
and multiplicity to the organisms which exhibited it? If so, then
Nature, at the time when life began on the earth, behaved in a manner
most unlike that in which she behaves at present. If we are to
interpret the processes hidden in the remote past by the light of what
we see at present, we shall conclude that, at bottom, the will to live
made molecular action—and the same force incorporated itself in the
combinations which originated protoplasmic life, ordered the structure
of the cell, and gave it the need and the power to multiply. Nature is
for ever changing, for ever straining after new life, after more life.

Having arrived at the cell with its powers of division, the next step
was the power of conjugation between cells with their interchange of
vital substance, bringing about, in Weismann’s words, “a wealth and
diversity of organic architecture which without it would have been
unattainable.” It takes place by means of physical energies, but the
process is entirely inexplicable unless we assume that it exists to
satisfy a need, a _Drang_, for life. And this need, although of course
it displays itself in physical processes, is not in itself a physical
process. At the very beginnings of structural life, if not before it,
we are obliged to pass beyond physics in order to comprehend physical
phenomena. Whenever we find an aggregate of living units, such as a
_Pandorina_ colony, living with a communal life which is other than
the sum-total of the lives of the individual units, we are in presence
at once of the necessity for a metaphysical conception, to render
intelligible the unity in diversity which we perceive.

The response of living protoplasm to the stimuli it receives from the
outside world is normally directed to the maintenance of the life and
form of the organism. The response of what is called ‘lifeless’ matter
is of another nature; not because it is really lifeless, for if it
were it would not respond at all, but because it has no organisms to
protect and foster. We all know the nature of the action of gravity on
Newton’s apple. It was treated as a dead substance, like a stone, and
gravity acted upon it as upon all other ponderable matter. But when
it had fallen to the earth, had decayed, and one of its pips began to
grow, the action of gravity began to be manifested in a quite different
and very peculiar fashion. It has been ascertained by a series of
ingenious experiments that gravity is the force which obliges the roots
of a plant to sink downwards into the earth. This does not, of course,
mean that the roots are drawn downwards by attraction of the earth,
but that the pull of gravitation gives a certain stimulus to the cells
concerned which makes them grow in that direction. Precisely the same
stimulus communicated to the cells of the stem has the very opposite
effect—these it causes to grow upright into the air and light. Thus
the roots are, as it is termed, positively, and the stems negatively,
geotropic. The substance of the root cells and of the stem cells is
the same, the stimulus is the same, but the effects on growth agree
in only one point, that they are respectively what the plant requires
them to be. There is no doubt that if a species of plants were placed
in such a position that it would serve them for the roots to grow
upwards, then upward-growing roots would eventually be evolved; in
fact, this is actually the case in the lateral underground roots of
certain mangroves which rise to the surface and become modified as
breathing organs, and in the aerial roots of various orchids, etc.[52]
When a change of habitat takes place calling for new developments of
structure to meet new conditions, these developments are not, as a
matter of actual observation, found to be mechanically ‘selected’ from
a mass of random movements and modifications of tissue—they reach their
goal, it is true, by a series of _gradual_ approximations, but the
goal is in sight from the beginning. In other words, _adaptability is
a fundamental character of life_. Hence the fact that multicellular
organisms which cannot, as a whole, fuse with others, adapt themselves
to these conditions by the allotment of special cells for that purpose;
while, again, the production of multicellular organisms is itself an
adaptation to Nature’s need for the higher organization of life.

    “The botanist Reinke,” writes Weismann, “has recently called
    attention once again to the fact that machines cannot be directly
    made up of primary physico-chemical forces or energies, but that,
    as Lotze said, forces of a superior order are indispensable, which
    so dispose the fundamental chemico-physical forces that they must
    act in the way aimed at by the purpose of the machine.... Organisms
    also [according to Reinke] are machines which perform a particular
    and purposeful kind of work, and they are only capable of doing
    so because the energies which perform the work are forced into
    definite paths by superior forces; these superior forces are thus
    ‘the steersmen of the energies.’”[53]

Weismann admits that there is “undoubtedly a kernel of truth in this
view,” but he is content with this perfunctory acknowledgment. His
main efforts are devoted to the substitution of fortuitously developed
“constellations” of molecular energy for any force which can be deemed
to have the slightest tincture of intelligence or purpose. “In our
time,” as he writes, “the great riddle has been solved—the riddle
of the origin of what is best suited to its purpose without the
co-operation of purposive forces.” The nature of the proposed solution
can be best described and discussed in another chapter, when we shall
be in a position to consider it in relation to the whole history
of organic development from its origin in protoplasmic life to the
evolution of species in plants and animals.




CHAPTER IV

    THE MECHANICAL THEORY OF EVOLUTION: THE DARWIN-LAMARCK EXPLANATION

    “Quelle est donc cette nature sujette à être effacée? La coutume
    est une seconde nature qui detruit la première. Pourquoi la coutume
    n’est elle pas naturelle? J’ai bien peur que cette nature ne soit
    elle-même qu’une première coutume, comme la coutume est une seconde
    nature.”—Pascal.


We now approach the _arcana_ of Evolution. The processes we have to
deal with in this chapter are not, and probably never will be, the
subjects of direct observation. All we can hope to do is to generalize
from the results which have risen to the surface of life about the
unseen forces from which they spring. The problem is to find (if
possible) a generalization which will cover all the facts relating to
that modification of natural forms, habits, and instincts which, when
it reaches a certain point, means the establishment of a new species.
We know that the thing happens, but we shall not understand _how_ it
happens until either the mechanism of the process is laid bare, or
until it is clear that we are in presence of an agency not entirely
definable in terms of mechanical action.

The fixity of species is maintained by a number of conditions, chief
among which must be reckoned the law of reproduction by conjugation,
with the consequent intermixture of numerous different lines of
descent. From one point of view conjugation, as Weismann so often
insists, greatly favours the adaptability of the organism to new and
varied conditions of life, inasmuch as it results in the mingling
together in each individual of a great number of varied determinants.
But when the conditions are constant, conjugation has also the
obvious effect of constantly reabsorbing, as it were, any heritable
abnormalities which may occur in individuals or the species, and
bringing them back to type. An individual possessing some abnormality
of structure will be most unlikely to find a mate possessing the same
abnormality—the mate will be either an ordinary individual or will
possess, if any, some quite different variation. Their descendants
will, therefore, usually show more resemblance to the normal type
than to the one abnormal parent, and in their descendants again, for
the same reason, the abnormal feature will be still further reduced,
until finally it disappears. It is only by the careful selection of
mates extending over many generations that pigeon-fanciers, to take
one prominent instance, are able to establish a new type. Left to mate
uncontrolled among themselves we should never have had the great
variety of breeds which have been produced by the art of the fancier
from the original rock-pigeon. The small variations which form the
starting points of his operations would, under natural conditions, have
soon been resolved into the normal type. What is it in nature, then,
that sometimes appears to play the part of the intelligent breeder and
to urge the plastic forms of life into new moulds?


The goal of the breeder is some new form which it pleases him
to produce, either for its use, or its beauty, or for its mere
singularity. The goal of nature, at least the apparent and immediate
goal, is the adaptation of each species to the circumstances of its
life. And the first thing that strikes the investigator is the way,
often indeed not perfect, but usually most impressive in its apparent
thoughtfulness and care, in which the organs of plants and animals are
fashioned to secure the most favourable results. But all this is the
result of development. The whale is a creature excellently adapted for
its present mode of life, but we know that it was once a furry land
animal with four legs; the legs are all there still, in modified or
rudimentary form, and the fur appears at a certain stage of embryonic
development. When we ask, How did this extraordinary transformation
come about? what we really mean is, How did the determinants composing
the chromatin in the reproductive cells of the original land animal
so come to alter as to produce the characteristics of the whale? For
new species can only be evolved by means of structural modifications
_capable of being transmitted by inheritance_; and nothing can be
inherited except through the action of the determinants. A modification
which does not affect the reproductive cells has no significance in the
evolution of species.

To this question Darwinism has given us our choice of two answers,
which may be termed respectively the Darwin-Lamarck and the
Darwin-Weismann theories. Lamarck explained the origin of species by
the accumulated effect of the inheritance, through many generations, of
modifications acquired by the exercise, or the disuse, of the modified
organs. Observing that living protoplasm responds to demands upon it
(thus, for instance, a muscle when systematically exercised attracts
more nourishment from the blood and grows stronger, and callosities
form to protect the skin of the hands of a manual worker), he assumed
that modifications so acquired might be transmitted by inheritance.
Each new generation, then, would start with a slightly better equipment
in this particular respect than the former one had when it started;
and so, by slow degrees, a new organ, or one markedly differing from
the original form, might be built up. The world, since protoplasmic
life first appeared upon it, has gone through many changes, and has
always presented a vast variety of climatic and other conditions,
calling for the most varied types of organic structure. As animal
life gradually spread over the earth and sea, the effort to cope with
the different conditions it met with would gradually, by the combined
action of exercise, of disuse, and of heredity, produce multitudes
of different types; and these are what we know as families, orders,
genera, and species. When a species is fairly well adapted to its
surroundings and way of life it may go on indefinitely without change.
But should any members of it be obliged to migrate, from scarcity
of food or any other reason, to some new locality where somewhat
different conditions prevail, structural alterations would soon begin
to appear to suit those new conditions. Thus the giraffe, if we could
trace its ancestry back, would probably be found to have originated in
some animal not differing from the vast majority of quadrupeds in the
relative proportions of its fore and hind quarters. But some members
of this original species—or the whole species, owing to some change
in their surroundings—found themselves obliged to rely largely for
food on leaves growing at a considerable height. They stretched up to
reach them, and a prolongation of the bones of the neck (the giraffe
has only the usual seven cervical vertebræ) and of the fore-legs would
ensue, especially in the young; this prolongation would be handed on
by inheritance, and so by degrees the new type of animal would be
evolved. The horn of the rhinoceros, the antlers of the stag, the
canine teeth of beasts of prey, the flat grinders of ruminants, the
flippers of the whale, the proboscis of the honey-feeding butterfly,
the jaws of the ant or the beetle, and a host of other adaptations
which seem obviously to owe their origin to the exercise of their
functions, occur to the mind in confirmation of this theory.

Besides Adaptation, we have what appears the strikingly confirmatory
case of what is called Co-adaptation, where the variation of one
organ or structure in an animal puts a strain upon other parts, which
accordingly respond by auxiliary adaptations. Such co-adaptations are
numerous in every animal structure, and, as we cannot suppose them to
have all originated simultaneously and by chance, the conclusion drawn
by Lamarckians is that one was produced by use, and, in the course of
its development, produced the others in the same way. A typical case is
that of the Irish elk. The enormous antlers of this beast, sometimes
weighing a hundredweight, must have needed (besides other structural
changes) a cervical ligament of immense size and power to support
them, and from the peculiar structure of the cervical vertebræ it is
demonstrable that such a ligament must have existed. What more natural
than to suppose that the antlers were developed by fighting wild beasts
of prey, combats between male elks, etc., and that then in their
gradual growth, as the species was evolved, the ligament and the bony
structure associated with it responded to the increasing strain. That
is exactly what would happen in an individual. We have only to assume
the heritability of modifications acquired by use to understand how
these co-adaptations became constant characters in a species.

Not less apparent cogency for the argument for modifications by use
have those cases where the modification has been apparently due to
disuse. It is well known that living creatures found in the total
darkness of great limestone caverns, like those at Kentucky, are
blind, through imperfections of one kind or another in the organs of
sight. But the rudimentary structures which remain tell us that these
creatures had ancestors which were once fully equipped in this respect,
and which had wandered into the caverns from the sunlit outer world.
Thus the case of a crab has been noted, in which the stalks on which
a crab’s eyes are set were preserved, while the eyes had disappeared:
it is, as Darwin observes, as if the stand of a telescope had been
retained while the telescope itself had gone. Sometimes the eyes
of cave-fishes are covered with a horny layer, sometimes the whole
structure is atrophied and withered. But never is an animal found
under these conditions which has retained its power of sight. The
conclusion seems obvious. In individuals, a muscle or other organ is
known to strengthen and develop by use and to atrophy by disuse. As use
and disuse appear to be invariably accompanied by precisely the same
effects in the species as in the individual, and as there seems no way
of accounting for this by any known physiological law without assuming
that modifications acquired by the individual are transmitted to its
progeny, the case for the inheritability of such modifications appears,
at first sight, irresistible.[54]

So matters stood when Darwin’s Origin of Species carried the argument
for evolution a long step further. Accepting fully the views of
Lamarck, Darwin attempted, by his doctrine of Natural Selection, first
to reinforce those views, secondly to explain much that they could
not be made to cover. It is plain that _if we assume the existence of
a severe competition for livelihood among the members of a species_,
any favourable variations of structure or instinct which may occur
among certain members of the species will give their type an advantage
over the normal type in the struggle for existence. They will, on the
average, live longer and produce more offspring. Ultimately, as the
struggle for life is always most severe among nearly related organisms,
which seek a living from the same sources, the less perfectly equipped
type will be extinguished, and so on, until a species exhibiting the
most complete form of adaptation has been evolved. The variations
on which Natural Selection has to work are produced, according to
Darwin, not only by the exercise of particular organs as in Lamarck’s
theory, but also and more potently by “innate variations” originating
from unascertained causes in the reproductive cells. Variations, it
is indisputable, are always occurring; probably no two members of
any species exactly resemble each other. Among low and primitive
organisms, such as the _Foraminifera_, Dr. W. B. Carpenter (I quote
from A. R. Wallace’s Darwinism) found, on careful examination, the
range of variation so great that characteristics typical not merely
of species but of genera and even of orders were liable to vary,[55]
while at the other end of evolution, in man, to give only one instance,
Mr. J. Wood is stated by Darwin to have observed no less than five
hundred and fifty-eight variations in the muscular structure of
thirty-six subjects examined.[56] The cause of these variations is
often quite obscure, but it is certain that some kinds of them are
capable of arising as the natural response of the organism to changed
conditions of food or habitat Conditions such as these, affecting
the whole constitution of the organism, have been proved capable of
affecting the reproductive cells, and thus of giving rise to hereditary
characteristics. Natural Selection, then, by preserving and encouraging
the better fitted as opposed to the less fit, acts as a spur to the
Lamarckian principles of development by exercise of function, while
it also lays hold of and intensifies all kinds of other favourable
variations occurring either casually or in consequence of change of
habitat, and weeds out the types in which such variations happen to
be unfavourable. According to Darwin, therefore, given (1) constant
variations of structure arising from use, disuse, or from other known
or unknown causes, (2) the capacity to transmit by inheritance these
variations _whether innate or acquired_, (3) a constant struggle for
existence among organisms both against each others’ competition and
against the general conditions of life[57]—given these simple data,
the secret springs of evolution are laid bare, and the vast complexity
of natural forms upon the globe is adequately accounted for without
calling in the agency of special creations. But variations are
the starting-point in the process: Natural Selection can originate
nothing—it can only act on what is presented to it by some quite
different force. The relative parts played by the various agencies at
work are, with characteristic moderation of statement, thus described
by Darwin:—

    “On the whole I think we may conclude that habit, use, and disuse,
    have, in some cases, played a considerable part in the modification
    of the constitution, and in the structure of various organs; but
    that the effects of use and disuse have often been largely combined
    with, and sometimes overmastered by the natural selection of innate
    variations.”[58]

To explain evolution, then, we must first explain _the occurrence
of appropriate variations_, strong enough and widespread enough
to maintain themselves against the constant reducing influence of
promiscuous intercrossing, and they must be variations _capable of
being transmitted by inheritance_. This, we now see, is the true field
of the inquiry.


The new factors introduced by Darwin into the process of
evolution—Natural Selection and Innate Variations—were destined
in our day to have the whole weight of the argument for evolution
suddenly thrown upon them. The inheritability of variations acquired
by the individual through use and disuse when subjected to fresh
investigation by the younger school of biologists has turned out to be
open to the gravest doubts, both theoretically, on account of the great
difficulty of reconciling it with what has now been ascertained of the
nature of the reproductive mechanism in plants and animals, and also on
the score of a closer consideration of the facts commonly adduced as
evidence for the law. To take these points separately: The reproductive
cells in every living creature are now believed to be formed directly
from the reproductive cells of its parents. They are not a product
of the organism in which they find themselves. They are nourished
by its blood, and are therefore liable to be affected by anything
which produces a broad general effect on the constitution of the
being in whom they are lodged, but it is difficult to see how special
modifications of individual parts of that being could affect them so
as to influence the determinants in the direction of reproducing that
modification. How, for example, could the habit of grubbing for roots
in an animal of the pig tribe so affect its reproductive cells as to
ensure the birth of an offspring with callosities on their snouts?
The physiological mechanism by which such a result could be produced
seems hardly conceivable—at any rate no one has yet offered a plausible
conception of it. Of course if the _fact_ were indisputably proved
one would only have to accept it, and endeavour, if possible, to
discover the why and how. But the fact, which once looked so solidly
established, is taking on a more and more insubstantial appearance in
the light of closer investigation.

The argument against Lamarckism rests on the basis (1) artificial
experiment, (2) of observation of nature under normal conditions.

As to the evidence from experiment, opinions fluctuated for some
time—Darwin was disposed at one time to deny, at another to admit the
alleged proofs it offered. In the present day opinion is overwhelmingly
against the validity of these proofs. The cases where artificially
produced mutilations are said to have been inherited have, when
investigated, turned out to be by no means as clear and trustworthy
as was supposed, nor can one place much reliance on a few cases of
striking coincidence such as are certain to occur from time to time.[59]

The adverse instances are very clear indeed. Chinese girls are never
born with abnormally small feet. Jews are not born circumcised. Among
tribes where tattooing is practised, no traces of this embellishment
are ever found to be inherited. If it is a physiological law that the
disuse of an organ not only atrophies it in the individual but (by
inheritance of the atrophy) eliminates it from the species, there is
no apparent reason why this law should not operate in cases where the
organ is artificially removed. Yet it rarely or never seems to do so.
Experiments upon animals, such as breeding for many generations from
mice whose tails have been cut off, have never resulted in producing a
clear case of inherited mutilation. A strong presumption is therefore
raised that the effects apparently due to use and disuse under natural
conditions (as in the eyeless fishes of the Kentucky caves) must be set
down to some other cause. The queens in colonies of ants and bees have
never exercised the functions of workers for thousands of centuries,
yet they transmit these functions unimpaired.

There is, indeed, a case often referred to in this connexion which
must be here mentioned. Dr. Brown-Séquard found that by injuring or
compressing the sciatic nerve in guinea-pigs epilepsy was produced, and
that the descendants of animals so injured had a marked tendency to
epileptic fits. This is undoubtedly a very significant and important
fact in biology, but it gives no support to the Lamarckian theory.
What is inherited by the guinea-pigs is not the injury to the nerve
but the pathological condition resulting therefrom. It remains to
be discovered how, precisely, this takes place, and the experiment
may end in illuminating a very obscure region in physiology, but on
Lamarckism it has no bearing at all. A better case is that of atrophy
of a toe, which is said to have been inherited in consequence of its
original production by severance of the sciatic nerve, but, again,
what is inherited is not an actual injury but an effect of it. It is
clear, however, that bodily conditions of a large and comprehensive
kind produced naturally or artificially in an individual may have an
effect on the reproductive cells, especially when the nervous system is
affected.

Coming to the observation of what happens under natural conditions,
we are struck at the outset by the fact that the inheritance of
acquired characteristics, if it works at all, must work under some
system of salutary control and not as a blind physiological law. For
if each generation starts with some measure at least of what the
former generation had acquired, and adds to it by its own activity,
then all acquired characteristics would ere long attain a monstrous
development, and the species would perish under them. But nothing of
the kind is observed to happen. The continual use of the muscles in the
labouring classes has not made men stronger than they were thousands
of generations ago. The habit of handling the spade and hoe has never
produced a peasant child born with callosities on its hands. The horn
of the rhinoceros, which on Lamarckian principles we must regard as
developed by the gradual increase of a callosity formed by grubbing for
roots, does not grow beyond a certain size, however the species may go
on grubbing. The Lamarckian law, then, if it has any real effect at
all, can only express half the truth about the action of heredity on
acquired characteristics. As the column of water in a fountain hovers
about a certain height, so the action of heredity in the accumulation
of the effects produced by the use of organs seems to have a limit
beyond which it cannot pass. May it not be that heredity is really as
false an expression for the phenomenon as the popular superstition
about ‘water seeking its own level’ is for the upspringing of a
fountain?

The cases of co-adaptation, where one organ appears to be developed
by use and others by the use of that, as in the case of the Irish
elk referred to above, are met by instances just as striking where
the elements of modification by use cannot come into play. Weismann
mentions the case of the ingenious brush arrangement on the anterior
legs of the bee, which the insect uses for cleansing its antennæ. Two
adaptations are here developed—a little semicircular notch in the leg,
set with small bristles, and a movable projection or flap used for
pressing the antenna into the notch as it is drawn through. The bee, no
doubt, would naturally try to clean its antennæ with its fore-legs, but
how could this process develop the special arrangements referred to in
the hard or scaly covering of its limbs? It is not until the shell of
the insect has grown quite hard and incapable of further vital changes
that the arrangement comes into use. Again, the stridulating noise
produced by the legs of the grasshopper is due to serrations occurring
on different joints of the limb. Serrations on one joint would in
no way tend to develop them on the other, but rather the contrary,
yet there they are, in harmonious co-operation. If Nature can obtain
these effects, as she does in numberless instances, without the aid of
Lamarck’s principle, we cannot help asking whether that principle is
ever operative at all.

The three instances which we shall next consider seem to offer very
serious obstacles to the Lamarckian theory.

A modification of structure caused by the special use of a certain
organ takes place in probably over 90 per cent of the whole human race,
male and female. The records of art, of language, and the evidence
of actual remains, tend to show that the habitude in question, with
the attendant modification, goes back to very ancient, even perhaps
to palæolithic times.[60] I refer to the preferential use of the
right hand and the enlargement of structure thus brought about in
the right hand and arm. Every right-handed adult man and woman shows
this enlargement of bony and muscular structure. The origin of the
habitude does not concern us here. Let us suppose it due, as Dr. D.
J. Cunningham suggests, to “a transmitted functional pre-eminence
of the left brain,”[61] which is larger than the right, and which
governs the movements of the right side of the body. However this may
be, it is clear that if bodily characteristics acquired by exercise
are transmissible by inheritance the new-born child of right-handed
ancestry ought to show some appreciable preponderance in weight and
size of the right over the left limb. There could hardly be a more
crucial test of the validity of the Lamarckian principle. What do the
investigations of the dissecting-room reveal? I shall quote the two
most recent authorities who have studied this interesting question. Dr.
Cunningham, in the lecture already referred to, writes:—

    “Although the matter has not been investigated so fully as to place
    the question outside the region of dispute, the evidence at our
    disposal distinctly favours the view that at birth the two upper
    limbs start upon their individual duties equally endowed in so far
    as strength of muscle and size of bones are concerned. Both in mass
    and weight the two limbs are to all intents and purposes similar at
    birth, and the preponderance in bulk and strength which later on
    distinguishes the right arm is acquired during life, and is caused
    by the greater amount of work it is called upon to perform.”[62]

Dr. T. G. Moorhead, Chief Demonstrator in Anatomy in Trinity College,
Dublin, after giving the results of the researches of various other
inquirers, writes:—

    “From this mass of conflicting evidence I am forced to the
    conclusion that no real differences exist.. .. After weighing as
    a whole the limbs of eight foetuses I was unable to detect any
    constant difference.”[63]

These results appear to conflict most seriously with the theory of the
transmissibility of acquired modifications.

[Illustration: Fig. 3.

_Kallima paralecta_, as it appears at rest, with wings closed.

From Weismann’s The Evolution Theory.

K, the head; B, the limbs.]

Every one is familiar with the fact that species of animals which
are preyed on by others, or which require to be inconspicuous
for the purpose of preying, are very apt to take the colour of
their habitual surroundings. Individuals of the same species will
even differ according to their special habitat. Perhaps the most
marvellous instances of this kind of adaptation are to be found in
certain tropical butterflies, such as the Indian butterfly, _Kallima
paralecta_, here illustrated. We have here, painted on the butterfly’s
wing, the picture of a leaf belonging to a shrub which it frequents—a
picture, when seen under natural conditions, capable of baffling all
but the closest inspection. The different parts—the midrib, the lateral
veinings, the little blotches and spots which represent patches of
mould or drops of water, even the outer contour of the wing itself—all
form an harmonious whole composed of related parts which have
separately no meaning or use. They certainly did not all appear in full
development at the same time. Nor could any one of them, if it appeared
first, have exercised the smallest influence on the appearance of the
others, as the antlers of the elk were supposed to have influenced
the development of the _ligamentum nuchæ_. The early stages must have
been anticipatory of the later ones, but exercise could have had
nothing to do with the result from first to last. The butterfly never
practised looking like a leaf. Nor can any large chemical and elemental
influences have been at work. If nature is capable of producing such
effects as this without the agency of Lamarck’s principle, are there
not excellent grounds for seeking for some other agency which will
cover all the phenomena alike?

Finally let us take the case of the slave-owning ‘Amazon’ ants,
_Polyergus rufescens_. Here we have a case which at the first blush
looks like a perfect picture of an evolutionary process conducted on
the principles of Lamarck’s theory. These ants, it may be supposed,
were originally of the ordinary type of that industrious and
respectable insect, but they were led by the weakness of some of their
neighbours of another species to make occasional attacks on them for
the purpose of carrying off their immature brood, the _pupæ_, as food.
Some of these _pupæ_, near maturity at the period of their capture,
would come out while stored-up in the nest of the conquerors, and when
they did so would immediately set about doing the household work of
the hive as if they were at home. _Polyergus rufescens_ ultimately
became aware that a life of aristocratic leisure awaited him if he
only captured enough _pupæ_ of another species of ant to do his work.
He accordingly confined himself entirely to piratical expeditions of
this nature, and in the course of time underwent a moral and physical
transformation of a most remarkable kind. The ordinary ant instincts
have disappeared in this variety. They do not make their nests, they
do not gather stores, they do not mind their young, they do not even
feed themselves—an Amazon ant will perish of starvation in the presence
of food if there is not a slave ant to put it into his mouth. But
they fight ferociously in their slave-raids, and the form of their
mandible has changed to suit their mode of life. It has become a pair
of sabre-like nippers, excellent for slaying a foe, but ill-adapted
for carrying objects and other industrial occupations. Corresponding
changes have taken place in the head and in the chitinous and muscular
structure.

We have before us, then, what would seem to an uninformed observer,
a striking picture of the acquirement of a certain bodily form and a
certain set of instincts by use, and the total loss of other traits by
disuse, and of the fixing of these characters in a species by heredity.
Yet the picture is altogether an illusion. However we are to explain
the facts—of which more anon—we cannot do so by Lamarckism, for the
simple reason that the peculiar instincts and bodily structure of the
Amazon ants are confined to the so-called ‘worker,’ or in this case
‘soldier,’ caste, which are sexless, and incapable of reproducing their
kind. If these were the individuals which originally started the slave
system among the species, they could not possibly have transmitted the
modifications, moral and physical, which they acquired. The queen-ants,
which normally are the only fertile ants, transmit them, but do not
possess them, and neither do the drones.

The case of these mysterious communities of insects, composed largely
of neuters which do the work of the community but do not reproduce
their kind, was one of the difficulties in the way of Darwin’s theory
of evolution which, he said, staggered him every time he reflected
on it.[64] It is not surprising, therefore, that this difficulty
came to be the battlefield, or a main position thereof, in a most
interesting and illuminating controversy on Natural Selection _versus_
Lamarckism, waged between Mr. Herbert Spencer and Dr. Weismann in the
years 1893-4.[65] Spencer considered the inheritance of acquired
characteristics a factor in evolution of the very first importance;
and so, indeed, from his point of view it is. “Either,” he declared,
“there has been inheritance of acquired characteristics, or there has
been no evolution.” Met by the case, among others, of the slave-making
ants, his explanation is substantially as follows: It was not the
workers (soldiers) which originally acquired military traits, but the
queens, the fully developed females, which lost them. There was once,
as every one admits, a time when all ants, bees, etc. were sexually
mature. There were only males and females. At this stage, possibly, the
Amazon ants were already predatory. It was _then_ that they may have
acquired the military habits and structure, which they were then able
to perpetuate by inheritance.

How, then, did the queens lose these traits? “From the queens,” replies
Spencer, “they have slowly disappeared by inheritance of the effects
of disuse.” The obvious and unanswerable rejoinder made by Weismann
and his followers was that Spencer had only shifted the difficulty
to another ground—from the workers to the queens. If the queens (and
drones) lost the military characteristics by disuse, how do they come
to transmit them unimpaired to the workers? It is the very essence of
Lamarckism that whatever modifications are produced by use or by disuse
shall be transmissible by inheritance.

In this controversy, however, there was another string to the
Lamarckian bow. Worker-ants, bees, etc. are imperfectly developed
females. They have four or five egg-tubes where the queen has two
hundred, but they cannot be fertilized by the drones. It occasionally
happens, however, that these neuter insects do lay a few eggs. These
unfertilized eggs always develop into drones. One of these drones
might, it was suggested, now and then fertilize a genuine queen, and
thus hand on the traits of the worker from which it sprang. But apart
from the fact that an occasional occurrence of this sort would hardly
suffice to maintain the worker-characteristics unimpaired throughout
the ages, there is the decisive answer, as Weismann points out, that
we know at least one species of ant in which the evolution of a
neuter caste is absolutely complete, for the workers of _Tetramorium
caespitum_ possess no egg-tubes at all. Yet the transmission of
characteristics from queens and drones who never exercise them to
workers who cannot pass them on, goes forward in this species of any
ant just as in any other.

Nature, therefore, while doing in the case of these insect communities
exactly what she appears to be doing elsewhere by the accumulation
of acquired characteristics, must, in reality, have been working on
entirely different lines. If we can discover what those lines were,
they will cover the apparently Lamarckian cases as well, but the
Lamarckian principle certainly will not cover these.

In the next chapter we shall review the alternative explanation offered
by Darwinism, the explanation of Weismann; and we shall see whether
Spencer was not as successful in demolishing it as Weismann was in
showing that, if evolution exists at all, some other basis must be
found for it than that on which it was so largely rested by Herbert
Spencer.




CHAPTER V

    THE MECHANICAL THEORY OF EVOLUTION: THE DARWIN-WEISMANN EXPLANATION

    “Chance guides all things: mind and forethought must call it God
    alone!”—Menander.

    “In the end,” writes M. Edmond Perrier, “every imaginable theory of
    evolution must lead up to one or other of two absolute doctrines,
    essentially antagonistic to each other. Either the inheritance
    of acquired characteristics must be admitted in its full scope
    (_dans toute sa généralité_), or else we must believe in the
    predestination of protoplasm, developing by virtue of its own
    internal forces. But in the latter case we pass from the domain of
    pure science to enter that of metaphysics.”[66]


We have now to consider the most conspicuous attempt made in recent
times to escape from this tragic dilemma.

If the acquired and inherited variations of the Lamarckian theory drop
out as a contribution to the explanation of evolution, we are reduced
to two forces only—_innate_, or germinal, variability of offspring,
and natural selection. Indeed it might be said that we are reduced
to variability alone, since natural selection can do nothing until
suitable variations are presented to it. The suitable variations do,
however, turn up, and the question is, what causes them? The real
difficulty for the school of biologists who, like Weismann, “assume
the mechanical theory of the world to be correct,” is how to reconcile
the aptness and apparent purposefulness of these variations with any
mechanical theory.

    “We are justified in inquiring,” writes Weismann, “whether the
    assumption of ‘chance’ germinal variations, which we have hitherto
    made with Darwin and Wallace, affords a sufficient basis for
    selection. Osborn says very neatly in this connection, ‘We see with
    Weismann and Galton the element of chance; but the dice appear to
    be loaded, and in the long run turn “sixes” up. Here arises the
    question, What loads the dice?’”[67]

What loads the dice? There is the great question in which the realms of
biology and of philosophy meet each other! Through that borderland no
definite frontier has ever been traced, for in thought as in matter the
saying is true that natural groupings have nuclei, but no boundaries.
It is all the more essential that men of science should understand
philosophy and its methods, and that philosophers should understand
science. It is to be feared that at present the second of these
desiderata is much more fully realized than the first.

However, we have to see now what Weismann, protagonist among
contemporary biologists of the mechanical theory of the world, has to
answer to the crucial question which he has allowed Osborn to set him.


The problem is to discover how innate, germinal variations can come
about, of such a nature as to adapt an organism with striking accuracy
to its surroundings and way of life, without our assuming either (1)
that the exercise of function had any influence in causing heritable
variations, or (2) that they were caused by any non-mechanical power,
which, so to speak, had in view the objects which they fulfil. For
the variations are to be regarded, on Weismann’s theory of life, as
completely _fortuitous_ in respect of the objects they serve. How,
then, do they come to serve them, in most cases, so admirably well?

The general nature of Weismann’s explanation may be summed up in a
curious illustration given by him in The Evolution Theory.[68] Let
us suppose, he says, a snow-field surrounded by precipices on all
sides, but with a narrow track leading away from it at one point.
Scattered about on the snow-field are a number of persons. A sleigh is
now projected among them from some outside point. Each person, when
the sleigh comes near him, gives it a push, but he has no object in
pushing it anywhere in particular, and simply sends it flying off in
whatever direction he chances to be looking. What will happen under
these circumstances? After more or less bandying about, the sleigh
will, in the vast majority of cases, fall into one of the abysses round
the snow-field and be lost But another is then launched on to the
snow-field, and then another and another without end; and so, at last,
it may happen that a series of pushes will take place which will send
the sleigh over the narrow track to its goal.

The goal is supposed to represent some condition to which the
organism (the sleigh) has to adapt itself. The random pushes which
it receives are the multitude of variations constantly occurring in
the reproductive cells. Most of these variations have no decisive
tendency, favourable or unfavourable. If a series of unfavourable
ones should occur, leading to some development which markedly impairs
the chances of the organism for success in life, it, or its line of
succession, dies out, and the unfavourable variation is, therefore, not
perpetuated. This is illustrated by the sleigh going into the abyss.
But if a favourable variation occurs, and is increased till it reaches
‘selection value,’ _i.e._ till it gives the organisms possessing it
a distinct advantage over others in the battle of life, then this
favoured type will ultimately, by the action of natural selection,
drive out the less favoured, and will establish itself as the sole
representative of the species. Having reached this level, of course the
same process will go on further indefinitely.

Before criticizing this conception of evolutionary processes, we
must inquire into the vital point of how the variations, the random
pushes given to the sleighs, ever rise to such intensity as to
have selection-value, and to make head against the influence of
intercrossing. The explanation is certainly ingenious, but is so purely
hypothetical and has an air so fantastic that it has commended itself
to very few students of biology. Weismann would have us suppose that
the determinants of which the hereditary substance in the reproductive
cells is made up are carrying on with each other an incessant struggle
for nutriment. If one of them succeeds in getting a little more than
its neighbours it thereby grows stronger, and is able to attract
still more nutriment to itself, and to impoverish those around it. It
is thus launched, as it were, on an ascending scale, and will go on
automatically if the variation caused by it proves favourable to the
species. If it proves unfavourable (which _ex hypothesi_ it is just
as likely to do) its career will be put a stop to by the extinction
of the line of descent which inherits this variation. Weismann’s
theory of “Germinal Selection” is therefore simply an application to
the reproductive cell and its contents of the Darwinian principle of
Natural Selection.

The theory is one which plainly makes immense demands upon our
faith. As regards the existence of a continual competition among
the determinants, there may be reason to accept it, but hardly in
the Weismann sense. Suppose two parents to unite, one healthy,
well-nourished, full-blooded, the other starved and weakly, it is
very likely that, in the resulting offspring, other things being
equal, the determinants coming from the well-nourished frame will be
seen to have surpassed in potency those from the weakly one. For the
determinants are living protoplasm—they depend on nourishment derived
from the blood of the organism in which they are lodged, and they
are capable, no doubt, of being well-nourished or ill-nourished or
possibly over-nourished, according to the constitution and history of
that organism. But this is a very different thing from supposing that
one determinant can begin to grow in _the same cell_ at the expense
of another, when both are absolutely embedded in an ocean of the same
nutritive matter. There is not—of course in the nature of things
there cannot be—a particle of evidence for the supposition. It is a
pure imaginative hypothesis, and on the face of it a most improbable
one. It is difficult to believe that it could ever have been adopted
save as a desperate attempt to break through the ever-narrowing ring
of evidence which is forcing investigation more and more towards a
non-mechanical explanation of the processes of life. But even if it
were true, what is gained by it? “Appropriate variational tendencies,”
writes Weismann, “not only _may_ present themselves, they _must_ do so,
if the germ-plasm contains determinants at all by whose fluctuations in
a plus or minus direction the appropriate variation is attainable.”[69]
But why _must_ they? There is no ‘must’ about Chance, unless one
extends its operations to infinity. Why is it so certain that the
inequalities of nutriment, on which hereditary variability is supposed
to depend, must necessarily run the gamut of all possible variations?
There is no ‘must’ in this theory, except that it is the last ditch
of the “mechanical conception of the economy of life.” It ‘must’ be
true—or that conception must quit the field.

Were evolution to depend on the occurrence, by pure chance, of a
few appropriate variations among a vast multitude of indifferent or
disadvantageous ones, is it conceivable that we should find in nature
anything like the infinite wealth of closely and beautifully adapted
structure which is actually present? In particular, how are we to
account for the cases in which a number of parts are so modified as
to work together in harmonious co-adaptation? Each of these parts,
according to Weismann, originates quite independently of the others.
Take the case of the Indian leaf-butterfly already referred to.[70]
The first beginnings of the midrib on Weismann’s theory had nothing to
do with the rest of the rib, nor had any of the veinings with this, or
with one another; and the contour of the leaf, sending out a little
projection like a stalk _exactly where the midrib starts_, originated
quite independently of that marking, and equally so of the leaf it
mimics! To explain co-adaptations like this on Weismann’s theory is
really much the same as to suppose that a picture could be painted by
simply plastering the scrapings of a palette on a canvas, if only one
continued the process long enough. And the marvel in question, the
co-adaptation of various parts, has not been attained once or twice
but, to a greater or less degree, in _every_ organism possessing any
structural complexity.

The difficulty, of course, has not escaped Weismann. His explanation
depends on some conception of the potentialities of conjugation and
intercrossing which I confess I cannot understand. He finds the key to
the mystery in the mingling and constant recombination of determinants
from different individuals produced by promiscuous intercrossing. “It
is only through amphimixis [conjugation] that simultaneous harmonious
adaptation of many parts becomes possible.”[71] But surely this
continual mingling and recombination would, _primâ facie_, be just as
likely to break up co-adaptations already forming as to give rise to
new ones? Amphimixis, as we have seen, is one of the most potent forces
against which the evolution of a new species has to contend. Evolution
has to make head against the constant tendency of intercrossing to
obliterate individual distinctions. True, if parents exhibiting
the same heritable variation unite, their offspring will have that
variation in a strongly marked form, and will transmit it further. But
this, to be of value for evolution, presupposes the same variation
occurring simultaneously in a number of individuals within reach of
each other. Weismann had indeed good reason to ascribe to the action of
intercrossing “a wealth and diversity of organic architecture otherwise
unattainable,” but were it not supplemented by an architectural
instinct of nature, the only architecture attainable would be that of
the child when it empties its bricks on the floor.

Consider the theory of germinal selection in the light of the following
very curious case.[72] Most people have seen an example of the kind
of spectacles having what are called bifocal lenses. Each lens is
divided across the centre, and the focal lengths of the upper and
the lower halves are different. They are intended for persons who see
indistinctly both at near and at far distances—the upper half of the
lens is used for looking at distant objects and the lower for reading,
etc., so as to avoid the inconvenience of having a different pair of
glasses for each requirement. Now there is a fish, named _Anableps_
(the Uplooker), living in estuaries on the east coast of South America
which actually has its eye-lenses constructed on this principle. The
pupil of the eye is divided laterally by prolongations from the iris.
The significance of this extraordinary arrangement is that the fish
is in the habit of swimming near the surface, and often has its eyes
wholly or partly out of water, presumably to look out for attacks from
birds of prey. The upper half of the eye has become adapted for vision
in the air and the lower for vision in the water.

According to Weismann, the habits and needs of the fish could have
had no influence whatever in producing this peculiar adaptation as an
inherited characteristic of a species. Any other fish or mammal would
have been just as likely as _Anableps_ to begin the development of a
bifocal eye. How does it come, then, that from the thousands of species
of eyed animals one, and one only, possesses this bifocal eye, and that
precisely the one which so greatly needs it? Weismann’s answer would
doubtless be that, in the case of other creatures, Natural Selection
would not have acted in protecting the individuals which possessed
the bifocal eye and penalizing those which did not. But can we imagine
that this principle acted very strongly when the bifocal arrangement
in _Anableps_ was in a mere rudimentary stage, as it must at first
have been? And should we not occasionally see at least traces of the
arrangement in the eyes of other creatures, if its full development in
_Anableps_ was merely the result of Natural Selection laying hold of
and perfecting an originally quite fortuitous variation?

A case still more curious and convincing occurs in connexion with
the hermaphroditism exhibited by a whole class of animals belonging
to many different orders, but alike in the one respect that it is
specially desirable for them to have both sexes comprised in the same
individual. These are animals capable only of sluggish movement, the
different sexes of which have therefore some difficulty in finding
each other out. Terrestrial snails and slugs are an example. All these
creatures are double-sexed; any two snails which meet can conjugate,
since each can act either as male or as female at will. Oysters are
another instance, though in this case the two sexes follow each other
at different periods in the life-history of each individual. Clearly,
this faculty gives to snails and slugs twice as many opportunities of
reproducing their kind as if the sexes were distinct. It is certain
from general biological considerations that they were distinct
originally. One can easily understand how, if any small group of the
original species from which all the present tribes are descended,
happened to throw up these bisexual peculiarities, their progeny would
multiply faster than the rest and might ultimately exterminate them
by the operation of natural selection. _But exactly the same might be
said of any other tribe of unisexual animals._ Any of these might,
_a priori_, on the “mechanical conception of the economy of life,”
be just as reasonably expected to develop bisexuality; for no one
supposes that there is any physical connexion between sluggishness
and hermaphroditism, or swiftness and distinction of the sexes; and
the causes which have operated to extend and confirm the type in
sluggish and sedentary animals would have the same effect in swift
ones. Yet this remarkable adaptation occurs just wherever there is
special need for it; there always and there only. What mechanism can
account for such a phenomenon as this? No; the dice are loaded. Nature
gains her end slowly and not without hesitations and failures, but the
phenomena are wholly unlike the results of the play of uncontrolled
and fortuitous forces. Imagine a blindfolded archer shooting arrows
upwards, downwards, and all around him in every direction as it may
take his fancy. There is, unknown to him, a target some distance
off. If he went on long enough it is conceivable, though by no means
necessary, that some arrow would hit the bull’s eye. But the facts
plainly point not to the above analogy, but rather to an aim at a
desired object. Some of the arrows miss, some light near the mark,
others hit it precisely. The flight, on the whole, is in the right
direction, as the immense proportion of complete or partial successes
plainly proves.


The two pillars of Weismann’s theory of evolution are _germinal
variation_ and _natural selection_. The one is supposed to originate
ceaseless changes of structure, the other to eliminate those changes
which are useless[73] or unfavourable and to foster and confirm the
favourable. We have seen, if the foregoing considerations are sound,
that fortuitous variations do not provide the material with which
natural selection can build up a universe of organic life like ours. We
have now to turn our attention to the other prop of the system and to
inquire whether natural selection can play and does play the part which
Darwin and his school assign to it in the economy of nature.

Natural selection is supposed to depend for its efficacy on the
existence of a state of strenuous competition for nourishment, or
for the avoidance of foes, in the type out of which the favourable
variations emerge. But in recent times the fact of any such
competition has been gravely doubted. Let us look back to the
beginnings of animal life in the world. The first primitive animal
organisms found themselves swimming in a boundless sea of nourishment
and had no foes at all! Yet they developed into higher and higher
grades of life. Competition did not aid in the development of these
higher grades—it was they which ultimately created the state of
competition. What Nature then achieved without competition she is
equally able to perform now. Even now when the earth is swarming with
varied life competition plays a much smaller part than was taken for
granted in the first flush of Darwinism. Creatures of the same type but
on different grades of organization, like the hive-bee and the humble
bee, are constantly found side by side, drawing their nourishment
from the same sources, but each holding its own without difficulty.
Facts like these were not unobserved by Darwin, who met them by the
supposition that competition came chiefly into play at exceptional
periods, during a drought, an inundation, a severe winter, or the like,
in which the less fitted members of the race perished wholesale. But,
as Kropotkin, in his interesting work, Mutual Aid among Animals, has
remarked,

    “If the evolution of the animal world were based exclusively, or
    even chiefly, upon the survival of the fittest during periods of
    calamities; if natural selection were limited in its action to
    periods of exceptional drought, or sudden changes of temperature,
    or inundations, retrogression would be the rule in the animal
    world. Those who survive a famine, or a severe epidemic of cholera,
    or small-pox, or diphtheria, such as we see them in uncivilized
    countries, are neither the strongest, nor the healthiest, nor the
    most intelligent. No progress could be based on such survivals—the
    less so as all survivors usually come out of the ordeal with an
    impaired health, like the Transbaikalian horses just mentioned,
    or the Arctic crews, or the garrison of a fortress which has been
    compelled to live for a few months on half rations, and comes out
    of its experience with a broken health, and subsequently shows a
    quite abnormal mortality.”[74]

Kropotkin’s book shows good reason to believe that the principle of
mutual aid and support plays at least as great a part in the animal
world as does that of mutual competition and extermination.

That the competition of organisms, animal and vegetable, for
nourishment and for protection may favour certain types, and depress or
even exterminate others, is of course indisputable. We see it when the
Japanese worker and the Californian meet in industrial rivalry on the
Pacific slopes—we see it when the willows planted by New Zealand rivers
destroy the weed which infested them, by absorbing the nourishment
from the river-bed on which it lived.[75] What we have to consider,
however, is the efficacy of competition in giving predominance and
permanence to a type differing but slightly in the initial stages
from that of the rest of the species, and differing but in a very few
individuals. We have to consider, in fact, whether natural selection is
not a consequence rather than a cause of evolution. On no mechanical
theory of evolution can we suppose that the first leaf-markings of the
butterfly, _Kallima paralecta_, were either at all pronounced in their
mimicry, or that they originated simultaneously in any large group of
the original species from which _Kallima paralecta_ sprang. Therefore,
with very small advantage in the way of protection from enemies, and
with the constant and powerful influence of intercrossing ever tending
to obliterate the distinctive leaf-marks, how could natural selection
alone enable the new, the mimicking type, to assert and develop itself,
as it has done not only in this particular species of butterfly but in
hundreds of species of the _Lepidoptera_ and other insects?

    “A considerable initial resemblance,” writes Mr. Beddard in his
    most valuable though somewhat chaotic work on this subject,[76]
    “may be fairly set down to other causes [than natural selection];
    because it is impossible to believe that a slight move in the
    required direction would be of sufficient importance to serve as
    material for the action of natural elimination.”

The most convinced Darwinian will hardly deny that the problem involved
in this case is a serious one.

Another singular fact to be noted in this connexion is the “conclusion
arrived at by the study of mimetic butterflies in all parts of the
world—that the females are far more liable to assume this method of
defence than the males.”[77] An instance in point, which has been
the subject of much discussion, is that of the yellow and black
swallow-tailed butterfly, _Papilio meriones_, found in Madagascar.
The island is supposed to be the original home of the species, and
here both sexes are much alike. On the mainland of South Africa,
however, while the male has undergone the very slight transformations
represented by the species _P. merope_ and _P. cenea_, the females
imitate closely three different species of the _Danais_ butterfly
which is protected by its disagreeable taste from the usual enemies of
the tribe, and which is altogether unlike in shape and coloration to
the swallow-tail. “The new forms,” writes Mr. Poulton, “have arisen
at so recent a date that many of the intermediate stages can still be
seen, while the parent form has been preserved unchanged in a friendly
land, where the keener struggle of continental areas is unknown.”[78]
The significance of such a fact as this is obvious. If mimicry arose
from fortuitous variations of colouring and of form, males alone
might show it in some species, females alone in others, and both in
yet others, but it is difficult to understand how we could arrive
at the actual condition, and find it either common to both sexes or
practically confined to the female. If, on the other hand, mimicry
and other similar adaptations are ultimately to be interpreted as the
common response of the species to the attack of its foes, it is quite
natural that the female, as the egg-bearer, the most important factor
in the continuance of the species, should be specially protected. It is
probable also that she is most in need of protection, as her functions
may render her rather more exposed than the male to attack. That
natural selection cannot have been the dominant factor in the case we
are considering seems clear; for how could it have acted at all without
a somewhat vigorous weeding out of unprotected forms? And, in that
case, what would have become of the unprotected males of the species?

Difficulties of this kind have, in different cases, been raised again
and again since the publication of the Origin of Species, and have had
to be answered so often that there seems good _prima facie_ ground
for doubting whether they have ever really been answered at all. The
strongest advocates of the pure mechanical theory are obliged, as we
have seen, to admit that the drift of contemporary scientific opinion
is to place little reliance on casual variation and natural selection
and to look for the driving force of evolution in other directions.[79]
In the introduction to Strasburger’s Text Book of Botany[80] we find
this important passage:—

    “The tendency is to assume the existence of a development of
    the organic world due to original, innate capabilities of the
    living substance and not dependent on selection. The origin of
    the large subdivisions of the animal and vegetable kingdoms,
    the ‘Archetypes,’ would be due to this sort of evolution. These
    archetypes have been, and are still, continually influenced by
    the environment, and, by their reaction to external conditions,
    organisms become more or less directly adapted.... The progressive
    evolution of the archetypes, as well as the direct adaptations to
    external conditions shown by them, is independent of selection.
    The latter does, however, exert an influence on the process of
    evolution of the organic world, though to a much more limited
    extent than was formerly supposed.”

It is clear that in these _original innate capabilities of the living
substance_ we have a power which alone _may_ fully account for the
evolution of the organic world, though natural selection can emphasize
and hasten its action. Its nature and limits are still undetermined.
Biologists are very chary of expressing this power save in terms of
chemistry and physics. Men of science are afraid—sometimes I venture to
think even morbidly afraid—of opening any door by which the fantastic
horde of arbitrary dogmas and superstitions which they have cast out
with so much toil and peril might find their way back into the temple
of Knowledge. But philosophy must warn them that in shutting out
all forces that cannot be weighed and measured in a laboratory they
may be shutting out life itself. And those who strenuously insist on
reducing nature to a mechanism often find themselves obliged to let
in the mysterious life-force by some more or less clandestine entry
in order to make their mechanism work. Thus Nägeli, the originator
of the theory of heredity which Weismann has developed, attributes
the phenomena of growth and evolution not to natural selection but
to “internal forces.”[81] He disclaims for these forces any but a
physical and chemical significance; but Professor Eimer, in spite of
all disclaimers, cannot get rid of the suspicion, well justified in
my opinion, that there is in these forces, as conceived by Nägeli,
something purposeful and teleological—admit them, he says in effect,
and who knows what we shall next be asked to believe?[82] Yet for Eimer
himself we find that, as Schopenhauer says, “the lotus of physics
is rooted in metaphysics.” Twice in his work on organic evolution,
he refers with approval to the view of “our profound philosopher,
Oken,”[83] who regarded all existing beings as members or organs of
some vast and transcendental organism whose development conditioned
theirs. Eimer even makes a somewhat daring application of this
principle to a concrete instance in the physical world, one which we
have already referred to, the problem of the inheritance of qualities
in ants, bees, etc., when these qualities are possessed and exercised
only by individuals who cannot transmit them.

    “We must regard,” he writes, “the different forms of bees, queens,
    drones, workers, as _discontinuous organs of one whole_, which have
    been evolved from a single indifferent ancestral form.... Only
    thus can we explain to ourselves the fact that the peculiarities
    of the workers, notwithstanding that they do not reproduce, are
    inherited.”[84]

When we are asked to believe in physico-chemical laws of such a
nature that they enable the habits of life of a worker-ant or bee to
react upon the germ-cells of the queen, just as the exercise of an
organ, on Lamarckian principles, affects the reproductive cells of
the creature to which it belongs, it becomes plain enough that for
modern investigators the so-called mechanical and the so-called psychic
conceptions of the universe are really running out at the same point.
The gulf between these conceptions, which seemed to yawn so widely
after Darwinism, was a mere illusion, arising from a point of view now
left behind.


To resume the argument of the foregoing chapters. We have seen that at
the basis of all theories of evolution lies the fact of the responsive
powers of living protoplasm. _But what does it respond to?_ That is the
question of questions. To put it accurately in relation to the process
of evolution we must ask, To what do the determinants in the germinal
cells of plants and animals respond? To what call did unicellular
organisms respond when they first began to interchange chromatin with
each other? To what, when they began to divide and form new organisms?
To what, when multicellular organisms began to specialize certain cells
for reproduction, and these cells to mature themselves for fusion by
throwing out half their chromosomes? And when the higher plants and
animals came on the scene, reproducing their kind under conditions
which make strongly for the fixity of species, how are we to interpret
the response of protoplasm when we see organs and structures melt away,
and others grow, giving rise to the innumerable types which yield us
the existing world with its overwhelming richness and variety of life?
Weismann tells us that the response is only to differences in the
amount of nutriment obtainable by the various determinants of the germ
cell, and has but a fortuitous connexion with the results attained.
We have seen the inadequacy of this theory, in the light of the many
adaptations such as that of which the fish, _Anableps_, with its
bifocal eyes, and the double sexual organs of terrestrial snails, are
types. Lamarck and Darwin, besides the belief in fortuitous variation,
held that heritable characters arise from exercise of function.
Innumerable cases can be quoted in favour of this explanation, but
we have seen instances in which it is absolutely untenable, and yet
where the required response takes place just the same. The influence
of light and colour tells on the colouring of animals, and impartially
protects them when they are preyed upon, or helps them to secure their
prey; and this influence is frequently explainable by chemical or
electric agencies originating in the environment of the animal, acting
on the blood, and thus influencing pigmentation of the skin,[85] but
chemistry is helpless to account for the manner in which nature shapes
the contour of the wing of a tropical butterfly and paints upon it
the veinings of a leaf, or protects a harmless fly by giving it a
resemblance to a stinging one, or protects a caterpillar by making it
look like a vicious and dangerous reptile. Yet all these protective
arrangements are evidently, at bottom, facts of the same order.
Protoplasm lives and responds not only discretely in the lowest unit
perceptible by the microscope, but collectively in the connected groups
of these units called multicellular organisms, and in the disconnected
groups of these organisms called species. It really responds not to the
exercise of function or to the play of physical forces, but to vital
tendencies of the organism. There seems an expansive force in nature
which, though working strictly under the dominion of physical laws, is
capable of using the combinations brought about by those laws for the
preservation and development of life. It is in love with life, it is
ever pressing toward action and self-realization, and all roads are one
to it if they lead to that end. In it are included the very chemical
and physical agencies which it obeys, and also that something beyond
which eludes the analysis of the laboratory.

How it acts, under what conditions, what limitations, why here in one
way, there in another, are questions of profound interest, the fringe
of which philosophy has hardly begun to touch. Nor is philosophy yet
in a position to do more, for the scientific conception of nature is
but a recent birth of thought; much remains to do in the collection and
organization of the facts with which the framework must be filled in,
and a philosophy which does not keep closely in touch with scientific
fact can have no message for the modern world. But it does seem
possible to discern, and it shall now be our endeavour to set forth,
in broad outline, certain principles of deep significance from which
we may obtain an answer to the question: What can we learn from the
physical universe that has a bearing on the spiritual life of man?




CHAPTER VI

THE DIRECTIVE THEORY OF EVOLUTION

    “Who is there that cannot distinguish between the actual cause
    of a thing and that without which the cause could never be a
    cause?”—Plato, Phædo.


The problem set at the close of our first chapter was to find a fit
explanation of the guiding power apparent in natural phenomena. We
have not been able to interpret this guiding power either in terms of
conscious, intelligent contrivance or in terms of blind, mechanical
law. The investigations which followed have led us up to another
explanation. We have seen that the vivifying, transforming, progressive
power in nature may be conceived as a power of Response. Every particle
of matter, organic and inorganic, has this power. Every particle of
matter can react and respond to some stimulus. The more it can respond
to, the higher it is in the scale of being. And we have found, as I
think, one constant and universal stimulus to which both the fixity of
nature’s laws and the plasticity of her mysterious substance may be
conceived as a response. This stimulus is the call of Life. Stimulus
and response taken together constitute the directive force in obedience
to which the world unfolds itself in the evolutionary process. We have
been led to interpret nature as the concrete expression of the will to
live, a will which for the first time comes into rational consciousness
in man. Having brought this conception, I hope, into clear light, it
is the aim of the present chapter to illustrate and enforce it in more
detail, and thus to gain a secure foundation for the application of
the conception to the more strictly human problems with which we have
ultimately to deal.

It must be confessed that the existence in nature of any directive
power transcending and utilizing the mechanical forces and relations
of matter, call it ‘vital force,’ the ‘hand of Providence,’ the ‘_X_’
of evolution, or what one will, has never readily been admitted by
scientific naturalists. They feel that, if once admitted, it offers a
prompt and facile explanation of every difficulty, and is available as
the cheap resource of all those who study nature with a view to the
grinding of their moral or religious axes, rather than to the discovery
of truth. Those who feel obliged to believe in the existence of some
such power are therefore bound to be more than ordinarily on their
guard against all loose thinking. They must not be content with vague
generalities, but must be prepared to indicate as exactly as possible
the distinction existing between the mechanical and the non-mechanical
or transcendental agencies in nature. It does not follow that one’s
account of the matter will prove to be exactly true in every detail.
One must always speak in such matters with that wise reservation of
Socrates, “If this be not the truth, something of the kind is.” But it
is not allowable to fall back on that “something of the kind” until an
attempt has been made definitely to establish the “kind,” by searching
into the inmost heart of the fact.

The fact here is the responsive power of living protoplasm. It will be
well to examine it first in its operation in an individual organism
before we consider it in relation to the species.

Reaction or response of a chemical and mechanical type takes place
alike in dead matter and in living organisms, but certain stimuli
will induce action in an organism which they could not possibly
induce in a mineral. For in every cell, as Reinke well says, there
are a chemist and an architect who guide its energies, and who have
something quite different from chemistry and physics in view. Consider
the following case. Every tuber of a potato plant is covered with
a light skin composed of a corky substance intended to protect the
internal structure from injury. This skin is produced by the action of
the surface cells of the tuber. Chemically and physically these cells
are just the same as the cells in the interior of the tuber. But the
interior cells do not produce this corky substance, because it would
be injurious to the plant if they did. The cells below the surface
of the tuber, though they are by no means secluded from the chemical
influences of the earth around them, behave quite differently from
those actually in contact with the earth.

Now let us take our tuber, slice it in half, and replace it in the
earth again. If we look at it again in a few days we shall find that
the interior cells, now exposed by the cutting, have done what they
could not or did not do before—they have produced a layer of skin to
cover the exposed surface of the tuber just as if they had been surface
cells from the outset.

This kind of response seems to take us quite out of the region of
chemical and physical action as understood in the case of inorganic
matter. It is a response directed to maintaining as far as possible the
life and form of the organism, a thing which mere chemical action in
mineral substances never does.

It may perhaps, however, be argued that the actual contact with the
earth has a possible chemical stimulus which is not communicable to
cells even a hair’s-breadth below the surface, and that the cells laid
bare by slicing react as they do simply because they are exposed to
this stimulus. Let us take, then, another common and typical case of
response to altered conditions in plant life.

The taproot of a tree, as we have seen,[86] grows straight downwards
towards the centre of the earth in obedience to the stimulus given
by the pull of gravitation. The same stimulus impels the stem to
shoot upwards, and the other roots and the branches to grow more or
less laterally. New growth always takes place at the extreme tip of
the shoot or root. Lay bare the taproot, cut away this growing tip,
and that root can grow no more; no fresh tip charged with vegetative
vitality can form itself over the scar. But mark what happens!
The nearest lateral root, instead of pursuing its normal course,
straightway begins to bend downwards and takes the place of the
mutilated taproot. Similarly if the leading shoot of the stem is nipped
off, the nearest lateral branch will turn upwards. In this case the
lateral root or shoot has not been subjected to any new influences
whatever, or at least to none of a chemical or physical nature. Yet it
responds, not to anything affecting itself, but to the needs of the
organism as a whole.[87]

None of the forces which living organisms have in common with minerals
will account for this kind of response.

How are we to represent to our minds the nature of the forces which
apply to the innumerable cases of which the above is a type? Reinke,
who deals exhaustively with this question, conceives the vitality of
living things, manifested in growth, development, and reproduction,
as lodged in what he calls “Dominants.”[88] These dominants exist
in all parts of the organism, and govern those processes which
ordinary physical laws do not explain, _i.e._ the phenomena which
are specifically vital. They are not themselves chemical or physical
energies, but they guide these energies toward the fulfilment of the
objects of life.

    “Dominants,” he writes,[89] “are those secondary[90] forces in the
    organism whose existence we recognize in their operations, but
    which we cannot further analyse. Thus I understand under this form
    that principle of control which takes effect in every organism and
    which sways whatever energies are available just as men use tools
    and machines. Since this control is manifold in its manifestations,
    one is obliged, when seeking for a technical designation for
    it, to express it in the plural. The dominants are therefore an
    abstraction; a symbol for phenomena, just like the conceptions,
    Force, Matter, the Atom, etc.; the term has been devised in order
    to provide a short explanatory description of certain essential
    processes.

    “I therefore repel the objection, if anyone should make it, that
    the dominants are a fiction, a troop of ghosts with which I have
    peopled the cells and organs of animals and plants. They are, in
    some sense, merely a paraphrase of the description of certain
    phenomena, a personification of forces not to be ranged under the
    conception of energy—the _directive_ impulses in the animal and
    vegetable world.”

To continue Reinke’s explanation: Two different classes of dominants
are to be recognized. These are the operative and the formative. The
former control principally the chemical activities of the organism, as
when a plant turns inorganic substances into sugar, albumen, etc.; the
latter are the invisible architects in the organism who control its
form and structure. Both are heritable, and are capable of modification
within certain limits. Closely bound up with matter and energy, they
are neither matter nor energy. They can be indefinitely multiplied and
(to all appearance) totally destroyed. Their multiplication does not
abstract energy from other known sources, nor does their destruction
restore it; they do not therefore come (visibly) under the law of the
conservation of energy. They operate entirely within the framework of
natural laws, and can only utilize what energies are available for
them at the given time and place. Every cell has its dominants; and as
an organism is a synthesis, not a mere aggregate, of cells, so its
individual dominant is a synthesis of the dominants of its parts. The
evolution of species, like the development of an embryo, is under the
control of dominants. The conditions under which they work for this end
are material and physical; these conditions can, to a great extent, be
ascertained and defined, but the driving force lies beyond scientific
analysis.

Such is the conception of Reinke; and taken as he presents it, that is
to say, merely as a kind of working hypothesis, as a means of making
intelligible a vast and various mass of phenomena, it seems admirably
suited to its purpose. It remains to add, though Reinke himself does
not say so, that this conception of the dominants appears to harmonize
remarkably with what has been put forward in regard to cell-structure
and reproduction. The chromosomes are probably the material vehicles
of the dominants; in fact, Weismann’s determinants seem to be the
same thing under another name, though Weismann conceives them rather
from the point of view of the scientist, and Reinke from that of the
metaphysician.


We have now arrived at an intellectual conception under which to range
the phenomena (not the ultimate nature) of vital response. Let us apply
it to the question of evolution. The following passage from Henslow’s
Origin of Plant Structures[91] may serve to introduce this part of our
discussion:—

    “The question ... resolves itself into this: which probability or
    hypothesis do _the facts_ of the case seem to favour most, viz.
    that _indefinite_ variations arise from some assumed internal
    causes, of which variations only those in harmony with the
    environment survive, and are said, therefore, metaphorically,
    to be selected by it; or is it that the external forces of the
    environment excite the variability which is inherent in plants,
    and call into action the responsive power of the protoplasm in the
    various species of plants, which thus _all_ tend to put on the
    same, or similar, or at least adaptive and _definite_ variations
    of one sort or another, so that there are _no_ indiscriminate or
    wasted variations[92] at all? I know an abundance of facts which
    support the latter contention, but none whatever in illustration of
    the former hypothesis.”

Here is the action of the dominants in evolution placed in the
clearest light. To prove the truth of Professor Henslow’s contention
it is necessary not only to study organisms in situations where they
have been established for many generations or centuries, but to see
how they behave on transportation to a new kind of environment. The
cases which can be adduced are numerous and convincing. Thus Mr. D.
Dewar reported to Mr. Henslow that on introducing at Kew a cress,
_Arabis anachortica_, found in cave-like situations in the Alps, and
having very thin, papery leaves, it turned, when raised from seed,
into a different species, _Arabis alpina_. The change took only three
generations to accomplish.[93]

Bulbous roots have it among their functions to store up moisture
for the plant they belong to. Haeckel has shown that the grass _Poa
bulbosa_, on being cultivated in moist soil, almost lost its bulbous
character. Contrariwise we find that many plants not bulbous elsewhere
are observed to be so when growing on the dry Karoo in South Africa.[94]

Spines on a plant are usual accompaniments of dryness in soil or
atmosphere. _Ononis spinosa_ has an excessively spiny variety, termed
_horrida_, which is found on maritime sands. Grown in very rich moist
situations, it gradually loses its spines and they ultimately disappear
entirely.[95]

In the animal world experimental cultivation is not at all so easy,
but the facts observed all go to support the view that the response to
environment is direct and definite. The small shrimp-like crustacean,
_Artemia salina_ is a case frequently quoted. It lives in salt pools
by the Black Sea, and it has been found that by breeding it in water
of which the salinity is gradually decreased, the creature in a few
generations assumes a type commonly assigned not merely to a different
species but to a different genus—_Branchipus stagnalis_.[96]

Perhaps the most remarkable instance of a transformation produced
by the influence of environment is that of the Mexican water-newt,
Axolotl. When gradually accustomed to live on dry land, this creature
usually throws off its gills, develops lungs, alters the shape of its
tail, and takes on all the characteristics of a terrestrial instead of
an aquatic reptile. This transformation does not take generations to
accomplish—it happens in one individual in the course of a few weeks
or months. When found in the terrestrial form, the Axolotl is called
_Amblystoma tigrinum_, and is classed among the salamanders. Its
progeny are then _Amblystomas_, and they do not naturally revert to the
Axolotl type, although under certain circumstances the steps of this
amazing transformation can be retraced. The Axolotl is not a larva in
the ordinary sense of the word, for it is not an imperfect creature;
it is sexually mature, and in most cases, in nature, probably never
develops into an _Amblystoma_, nor do the progeny of the _Amblystomas_
begin as Axolotls. What we have here is probably, as Weismann plausibly
suggests, a case of a species which has almost reached the stage of
evolution from an aquatic into a terrestrial form, so that a sufficient
impulse from its environment suffices to send it over the border.
Internal forces have evidently prepared the way for the change, and
the process does not in the least resemble the mechanical selection of
suitable characters from a crowd of fortuitous variations.[97]

The case of the Porto Santo rabbit may also be quoted in this
connexion. In the year 1419 the young born of a tame Spanish rabbit
were put ashore on the island of Porto Santo near Madeira. No rabbits
then existed on the island. They have since increased enormously, and
have quite changed their appearance. They have acquired a peculiar
colour, are very small, rat-like in shape, have nocturnal habits, and
are noted for their extreme wildness. They no longer pair with the
European rabbit. The case was observed by Haeckel, who styled the new
species _Lepus Huxleyi_.[98]


Cases like the foregoing show the organism affected during its process
of transformation by large elemental influences, and the response to
these influences is so familiar that often it does not surprise us. We
veil the real mystery of the process by talking of the chemical and
other physical properties of protoplasm which render this response
possible. But when we come to the protective mimicry of stinging
insects by stingless ones, of leaves by butterflies, and so forth,
these physical explanations manifestly fail us. The explanation
which assumes the building up of these extraordinary resemblances
bit by bit, through natural selection working upon a multitude of
fortuitous variations, fails us as completely. It would be difficult
to accept it if only a single species of insect showed these mimetic
markings. The unlikelihood of their production by mere chance in the
case not of one but of hundreds of species of butterflies, flies, and
caterpillars is stupendous, and defies all calculation. It must, we
repeat, always be borne in mind that, if chance variations are all we
can postulate, these variations must at first be confined to one or
few individuals, and that the influence of intercrossing would always
be at work to obliterate individual peculiarities before they could
develop to the point of affording any protection worth mentioning. We
are bound, therefore, so far as I can see, to conclude, first, that
these mimetic markings originate not in individuals but in the species
as a whole, and are an expression of the communal life of the species;
secondly, that they are a real and direct response to the external
conditions of danger from attacks of birds, etc., and of protection
afforded by deceiving these foes through mimicry of something which
they do not care to attack. They can only originate in the dominants
of the reproductive cells, and there, where undoubtedly forces and
affinities of which we have no conception are ever at work, the
initial changes take place. These changes, no doubt, take place by
forming new combinations or modifications of existing dominants. The
directive force must have something to work on. It does not follow
that because some things are possible to it therefore all things are.
It is not to be expected, for instance, that human beings, although it
would be a great advantage to them to fly, could ever develop wings,
like the conventional angels of mediæval art, for that would violate
the essential character of the archetypal form. It is true, however,
that life is ultimately responsible for the material with which it
works as well as the directive agency that breathes through it. This
point is of importance and must be made perfectly clear. The view of
cosmic action here put forward does not contemplate ‘interventions’
in the order of nature from a source outside it. There never was a
moment when, if _law_ prevailed, one result would take place, while
another result actually does occur in obedience to some mysterious
life-force. No; it is the life-impulse which makes the law, obeys it
and utilizes it. One can never say, “Such and such would have happened
if the life-force had not been in action, but, as it was, the event
was so-and-so”; for if it were not in action nothing would ever happen
at all—the Universe would be the Eternal Nothing. One might as well
speculate as to what would happen in a game of whist if nobody held
a trump. The voluntary limitations under which nature works resemble,
in the conception here put forward, the playing of a game, say a game
of ‘Patience,’ where there is only one player, who plays the game with
himself. There are laws to be obeyed, combinations which are necessary,
but a guiding force can take advantage of the conditions as they arise
and lead them to a certain end. If there were no laws and conditions
there would be no game. If, on the other hand, matter were absolutely
plastic life could not realize itself; nature’s game would be finished
ere it was begun. A concrete illustration may, while we are on this
topic, serve to suggest the kind of limitations under which nature
seems to work.[99] During the last century or so the African elephant
has been ruthlessly hunted down for its ivory, and since rifles and
expanding bullets came into play the process of extermination has been
greatly hastened. Elephants are now, I believe, protected by law over
a great part of South Africa, but if it were not for this the species
would at present be in considerable danger of extinction. The case is
very like that of the _Kallima_ butterfly and similar mimetic forms
before they acquired their protective markings. Now, how might we
expect nature to attempt the protection of the elephant? Doubtless by
increased fleetness, cunning, watchfulness, capacity of one kind or
another for concealing itself from hostile observation. But could we
look for any such development as, for example, a deterioration in the
quality of the ivory? Suppose, for example, the interior structure of
the tusk were to become spongy and cellular instead of being dense.
The tusk, if coated with hard enamel, might be almost if not quite as
useful to the elephant, but it would cease to be of any use for most
of the purposes to which it is now applied by man. The protection
would be most effective; yet we know that nothing of this kind can
possibly take place, though intrinsically the process would be far less
remarkable than the painting of the butterfly’s wing. It cannot take
place because it would either imply a supernatural knowledge on the
part of the evolution-dominants of the elephant tribe of the _reasons_
why it is hunted, or a conscious supervising and co-ordinating power
above nature, a manlike Deity, omnipotent and omniscient, such as Paley
assumed; to both of which explanations the actual processes of nature
stand uncompromisingly opposed.


It is much easier to say what the life-impulse is not than what it is.
I cannot, for my own part, conceive it as personal or conscious, in
the sense in which I feel myself a conscious person. If we ask, Has
it or has it not the quality of intelligence? we shall find both the
affirmative and the negative answers equally hard to square with the
facts. Our own intelligences working in a mysterious relation to a
bodily organism are perhaps fundamentally incapable of forming a clear
idea of the nature of the cosmic intelligence which is revealed to
us in the outside world, “like the dim view of a country seen in the
twilight, with forms half extricated from the darkness, with broken
lines, and isolated masses.”[100]

But those who find it difficult to believe that anything having
the nature of intelligence is at work in the physical world might
reflect on the striking analogy which that world offers to a certain
sphere where it is quite certain that the human spirit, including its
intelligence as well as its appetites and instincts, is the governing
power. Social institutions are a product of the human spirit. Yet the
development of these institutions is extraordinarily like that of the
functions and structures of an animal or vegetable organism. The value
of Mr. Herbert Spencer’s philosophic system may be disputed on many
points, but his elaborate analysis of the phenomena of social life and
his exposition of the minute analogies they exhibit to the processes
of evolution in nature must always remain a landmark indicating the
conquest of a great territory of human thought.[101] Here, as in
nature, we find a principle of movement and progress conflicting with
a principle of inertia. We find all grades of development existing at
the same time. We see the gradual progression, by means of all kinds
of by-ways, to a goal which one might have expected intelligence to
attain simply and directly. We see parallels in human societies to
arteries, nerves, to co-ordinating and ruling brain-centres, to the
specialization of different members or organs for different tasks;
and we see all these things growing up slowly, from point to point,
in obedience to immediate and pressing requirements. We find, both
in nature and in society, survivals of past structures, whose use is
gone, carried forward into new stages of development. A particularly
interesting analogy is that of structures which develop to meet one
kind of requirement, and, on the cessation of that, persist into a
further stage and are then modified to meet quite other requirements.
Thus the swim-bladder of the fish became, it is supposed, the lung
of the terrestrial animal. We may compare this with the development
of municipal institutions. Originally intended to enable bodies of
craftsmen and merchants to make head against the aggressions of a
feudal aristocracy they have survived the fall of feudalism, and have
become more important than ever as independent agencies for carrying on
the functions of social administration and education.

Thus, operations in the physical world which certainly do not look as
if they were the work of intelligence, as we understand it, are seen to
be closely paralleled by transactions in the history of man’s social
life. The development of life, in fact, is carried forward when the
plane of human consciousness is reached on just the same lines as those
which prevailed on the vegetable and the animal plane: there is no
breach of continuity in the broad outlines of evolutionary progress. It
is difficult to over-estimate the significance of this fact.

Perhaps nothing that man has evolved is so purely a work of mind as
Language. Here, the analogy with the phenomena of physical evolution is
very close and very illuminating. As in nature, the ultimate origins
are obscure—we can only form hypotheses as to how language came to
arise from the cries of animals, as we can only form hypotheses
how life arose from the play of molecular forces. But when both
are once established on the earth we see in them the same general
features—unity, in a few leading types, branching out into infinite
modifications in subordinate groups. Greek, Erse, German, Russian,
Sanskrit are all Aryan tongues and have all a common ancestry. They
differ widely among each other, but all alike are marked off from
the Semitic or the Mongolian families. So a man, a snake, a bear, a
fish are all vertebrates, and belong to a type essentially distinct
from that of a lobster or a snail. As in nature, we find all stages
of development existing at the same time—some lines of development
show a rapid advance, some a very slow one. Some types have, in both
cases, perished completely—there are fossil languages as there are
fossil species. A new invention, an advance _per saltum_, without
the utilization of existing constituents, is almost as rare in the
evolution of language as in that of species. Just as the lung is
developed from the swim-bladder, so the human mind, in the development
of language, takes hold of whatever existing form will suit its purpose
and transforms it to another end, as when it takes a word for ‘breath’
and makes it ‘spirit.’ There are laws governing the development of
root-forms, linguistic or physical, in various different orders or
species. The same osseous framework yields us in one class of animal a
hand, in another a hoof, in another a paw, in another (as in bats) a
wing. So in language the same root yields us the words, in different
languages, for _shining_, _showing_, _speaking_, _proving_, _a face_,
_a story_, _whiteness_. Another gives us, _young_, a _stepmother_,
a certain _musical string_, a _messenger_.[102] Contrariwise we see
both in nature and in language forms which have grown from entirely
different roots into a close external and functional similarity. What
unlearned observer would suspect that a whale was not a fish, and that
it descends from a furry land animal with four legs, or that the Latin
_Deus_ and the Greek _Theos_ with their perfect identity of meaning and
their almost perfect identity of sound have probably a widely divergent
etymological pedigree?[103]

On the other hand, the etymological identity of such words as _évêque_
and _bishop_ is as obscure on the surface as would probably be the
relationship of a greyhound with a bull-dog to an anatomist who saw
them only in fossil form.

Again we note that languages, like species, when they send out a
migratory colony, are capable of gradual transformation to meet new
conditions, and of marked divergence from the parent stock. Thus
English, as spoken and written in the United States, in spite of
the retaining influence of a common literary tradition, is steadily
diverging from the English of Great Britain.[104] So with the French
of Canada, the Spanish of South America, and the Dutch of the Cape. We
note also in both cases that curious phenomenon, the survival of the
useless relics of earlier structure, e.g. in the silent letters which
reveal the historic origin of innumerable English words, which are
paralleled in nature by the vermiform appendix of man, or the splint
bones in a horse, or the rudimentary legs of the whale or the python.

But analogies of detail like these, interesting as they are, are not
the main thing. The main thing is the _organic likeness_ prevailing
between the work of nature and this work of man—the likeness of growing
and developing structures, with their response to immediate needs,
their development by specialization of function, their lack of a
strict logical scheme, their anomalies and capricious variations, and
their control of these variations within certain archetypal forms. The
substance of language is sound, as the substance of life is protoplasm.
Phonetic laws govern the one as mechanical and chemical laws do the
other. But phonetic laws and the capability of producing sound could
never have made a language. The evolution of language is urged forward
by the constant pressure and expansion of human thought; and on human
thought, in its turn, it reacts, giving the stimulus and the starting
ground for fresh expansion. We have the heart of the analogy before
us now. _As thought acts on language so the pressure and expansion
of the life-impulse acts on the forms of matter._ Let us see whither
the comparison leads us. Language is a product of the human mind, but
not of _a_ mind. When a human mind consciously applies itself to the
fashioning of a language it produces Esperanto. If we were living in
an Esperanto universe, such as Paley makes out this to be, we might
draw Paley’s easy conclusions as to its Maker; but the rea

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