THE CONTROVERSY OVER THE SOUL
The Ideas of Immortality and God 83
PLATE III.--Embryos of Three Mammals 85
APPENDIX
EVOLUTIONARY TABLES
Geological Ages and Periods 115
Man's Genealogical Tree--_First Half_ 116
Man's Genealogical Tree--_Second Half_ 117
Classification of the Primates 118
Genealogical Tree of the Primates 119
Explanation of Genealogical Table 1. 120
POSTSCRIPT
Evolution and Jesuitism 121
INTRODUCTION
A few months ago the sensational announcement was made that
Professor Haeckel had abandoned Darwinism and given public support
to the teaching of a Jesuit writer. There was something piquant
in the suggestion that the "Darwin of Germany" had recanted the
conclusions of fifty years of laborious study. Nor could people
forget that only two years before Haeckel had written with some
feeling about the partial recantation of some of his colleagues.
Many of our journals boldly declined to insert the romantic news,
which came through one of the chief international press agencies.
Others drew the attention of their readers, in jubilant editorial
notes, to the lively prospect it opened out. To the many inquiries
addressed to me as the "apostle of Professor Haeckel," as Sir
Oliver Lodge dubs me in a genial letter, I timidly represented that
even a German reporter sometimes drank. But the correction quickly
came that the telegram had exactly reversed the position taken up
by the great biologist. It is only just to the honourable calling
of the reporter to add that, according to the theory current in
Germany, the message was tampered with by subtle and ubiquitous
Jesuistry. Did they not penetrate even into the culinary service at
Hatfield?
I have pleasure in now introducing the three famous lectures
delivered by Professor Haeckel at Berlin, and the reader will
see the grotesqueness of the original announcement. They are the
last public deliverance that the aged professor will ever make.
His enfeebled health forbids us to hope that his decision may yet
be undone. He is now condemned, he tells me, to remain a passive
spectator of the tense drama in which he has played so prominent
a part for half a century. For him the red rays fall level on the
scene and the people about him. It may be that they light up too
luridly, too falsely, the situation in Germany; but the reader will
understand how a Liberal of Haeckel's temper must feel his country
to be between Scylla and Charybdis--between an increasingly clear
alternative of Catholicism or Socialism--with a helmsman at the
wheel whose vagaries inspire no confidence.
The English reader will care to be instructed on the antithesis of
Virchow and Haeckel which gives point to these lectures, and which
is often misrepresented in this country. Virchow, the greatest
pathologist and one of the leading anthropologists of Germany, had
much to do with the inspiring of Haeckel's Monistic views in the
fifties. Like several other prominent German thinkers, Virchow
subsequently abandoned the positive Monistic position for one of
agnosticism and scepticism, and a long and bitter conflict ensued.
It is hardly too much to say that Virchow's ultra-timid reserve in
regard to the evolution of man and other questions has died with
him. Apart from one or two less prominent anthropologists, and
the curious distinction drawn by Dr. A. R. Wallace, science has
accepted the fact of evolution, and has, indeed, accepted the main
lines of Haeckel's ancestral tree of the human race.
In any case, Haeckel had the splendid revenge of surviving his old
teacher and almost lifelong opponent. Berlin had for years been
dominated by the sceptical temper of Virchow and Du Bois-Reymond.
The ardent evolutionist and opponent of Catholicism was impatient
of a reserve that he felt to be an anachronism in science and an
effective support of reactionary ideas. It was, therefore, with
a peculiar satisfaction that he received the invitation, after
Virchow's death, to address the Berlin public. Among the many and
distinguished honours that have been heaped upon him in the last
ten years this was felt by him to hold a high place. He could at
last submit freely, in the capital of his country, the massive
foundations and the imposing structure of a doctrine which he holds
to be no less established in science than valuable in the general
cause of progress.
The lectures are reproduced here not solely because of the
interest aroused in them by the "Jesuit" telegram. They contain a
very valuable summary of his conclusions, and include the latest
scientific confirmation. Rarely has the great biologist written
in such clear and untechnical phrases, so that the general reader
will easily learn the outlines of his much-discussed Monism. To
closer students, who are at times impatient of the Lamarckian
phraseology of Haeckel--to all, in fact, who would like to see how
the same evolutionary truths are expressed without reliance on the
inheritance of acquired characters--I may take the opportunity
to say that I have translated, for the same publishers, Professor
Guenther's "Darwinism and the Problems of Life," which will shortly
be in their hands.
JOSEPH MCCABE.
_November, 1905._
PREFACE
In the beginning of April, 1905, I received from Berlin a very
unexpected invitation to deliver a popular scientific lecture
at the Academy of Music in that city. I at first declined this
flattering invitation, with thanks, sending them a copy of a
printed declaration, dated 17th July, 1901, which I had made
frequent use of, to the effect that "I could not deliver any more
public lectures, on account of the state of my health, my advanced
age, and the many labours that were still incumbent on me."
I was persuaded to make one departure from this fixed resolution,
firstly, by the pressing entreaties of many intimate friends
at Berlin. They represented to me how important it was to give
an account myself to the educated Berlin public of the chief
evolutionary conclusions I had advocated for forty years. They
pointed out emphatically that the increasing reaction in higher
circles, the growing audacity of intolerant orthodoxy, the
preponderance of Ultramontanism, and the dangers that this involved
for freedom of thought in Germany, for the university and the
school, made it imperative to take vigorous action. It happened
that I had just been following the interesting efforts that the
Church has lately made to enter into a peaceful compromise with
its deadly enemy, Monistic science. It has decided to accept
to a certain extent, and to accommodate to its creed (in a
distorted and mutilated form) the doctrine of evolution, which it
has vehemently opposed for thirty years. This remarkable change
of front on the part of the Church militant seemed to me so
interesting and important, and at the same time so misleading and
mischievous, that I chose it as the subject of a popular lecture,
and accepted the invitation to Berlin.
After a few days, when I had written my discourse, I was advised
from Berlin that the applications for admission were so numerous
that the lecture must either be repeated or divided into two. I
chose the latter course, as the material was very abundant. In
compliance with an urgent request, I repeated the two lectures
(17th and 18th April); and as demands for fresh lectures continued
to reach me, I was persuaded to add a "farewell lecture" (on 19th
April), in which I dealt with a number of important questions that
had not been adequately treated.
The noble gift of effective oratory has been denied me by Nature.
Though I have taught for eighty-eight terms at the little
University of Jena, I have never been able to overcome a certain
nervousness about appearing in public, and have never acquired
the art of expressing my thoughts in burning language and with
appropriate gesture. For these and other reasons, I have rarely
consented to take part in scientific and other congresses; the few
speeches that I have delivered on such occasions, and are issued
in collected form, were drawn from me by my deep interest in the
great struggle for the triumph of truth. However, in the three
Berlin lectures--my _last_ public addresses--I had no design of
winning my hearers to my opinions by means of oratory. It was
rather my intention to put before them, in connected form, the
great groups of biological facts, by which they could, on impartial
consideration, convince themselves of the truth and importance of
the theory of evolution.
Readers who are interested in the evolution-controversy, as I
here describe it, will find in my earlier works (_The History of
Creation_, _The Evolution of Man_, _The Riddle of the Universe_,
and _The Wonders of Life_) a thorough treatment of the views I
have summarily presented. I do not belong to the amiable group
of "men of compromise," but am in the habit of giving candid and
straightforward expression to the convictions which a half-century
of serious and laborious study has led me to form. If I seem to be
a tactless and inconsiderate "fighter," I pray you to remember that
"conflict is the father of all things," and that the victory of
pure reason over current superstition will not be achieved without
a tremendous struggle. But I regard _ideas_ only in my struggles:
to the _persons_ of my opponents I am indifferent, bitterly as they
have attacked and slandered my own person.
Although I have lived in Berlin for many years as student and
teacher, and have always been in communication with scientific
circles there, I have only once before delivered a public lecture
in that city. That was on "The Division of Labour in Nature and
Human Life" (17th December, 1868). I was, therefore, somewhat
gratified to be able to speak there again (and for the last time),
after thirty-six years, especially as it was in the very spot, the
hall of the Academy of Music, in which I had heard the leaders of
the Berlin University speak fifty years ago.
It is with great pleasure that I express my cordial thanks to those
who invited me to deliver these lectures, and who did so much to
make my stay in the capital pleasant; and also to my many hearers
for their amiable and sympathetic attention.
ERNST HAECKEL.
JENA, _9th May, 1905_.
CHAPTER I
THE CONTROVERSY ABOUT CREATION
EVOLUTION AND DOGMA
EXPLANATION OF PLATE I
GENEALOGICAL TREE OF THE VERTEBRATES
The genetic relationship of all vertebrates, from the earliest
acrania and fishes up to the apes and man, is proved in its
main lines by the concordant testimony of paleontology,
comparative anatomy, and embryology. All competent and
impartial zoologists now agree that the vertebrates are all
descended from a _single_ stem, and that the root of this is
to be sought in extinct pre-Silurian _Acrania_ (1), somewhat
similar to the living lancelet. The _Cyclostoma_ (2) represent
the transition from the latter to the _Fishes_ (3); and the
_Dipneusts_ (4) the transition from these to the _Amphibia_
(5). From the latter have been developed the _Reptiles_ (6)
on the one hand, and the _Mammals_ (7) on the other. The
most important branch of this most advanced class is the
_Primates_ (8); from the half-apes, or lemurs, a direct line
leads, through the baboons, to the anthropoid apes, and
through these on to man. (_Cf._ the tables on pp. 115-120).
Further information will be found in chapters xxiv.-xxvii. of
the _History of Creation_, and chapters xxi.-xxiii. of the
_Evolution of Man_.
PLATE I.
[Illustration: GENEALOGICAL TREE OF THE VERTEBRATES]
LAST WORDS ON EVOLUTION
CHAPTER I
THE CONTROVERSY ABOUT CREATION
EVOLUTION AND DOGMA
The controversy over the idea of evolution is a prominent feature
in the mental life of the nineteenth century. It is true that a
few great thinkers had spoken of a natural evolution of all things
several thousand years ago. They had, indeed, partly investigated
the laws that control the birth and death of the world, and the
rise of the earth and its inhabitants; even the creation-stories
and the myths of the older religions betray a partial influence
of these evolutionary ideas. But it was not until the nineteenth
century that the idea of evolution took definite shape and was
scientifically grounded on various classes of evidence; and it
was not until the last third of the century that it won general
recognition. The intimate connection that was proved to exist
between all branches of knowledge, once the continuity of
historical development was realised, and the union of them all
through the Monistic philosophy, are achievements of the last few
decades.
The great majority of the older ideas that thoughtful men had
formed on the origin and nature of the world and their own frame
were far removed from the notion of "self-development." They
culminated in more or less obscure creation-myths, which generally
put in the foreground the idea of a personal Creator. Just as man
has used intelligence and design in the making of his weapons and
tools, his houses and his boats, so it was thought that the Creator
had fashioned the world with art and intelligence, according to
a definite plan. Among the many legends of this kind the ancient
Semitic story of creation, familiar to us as the Mosaic narrative,
but drawn for the most part from Babylonian sources, has obtained
a very great influence on European culture owing to the general
acceptance of the Bible. The belief in miracles, that is involved
in these religious legends, was bound to come in conflict,
at an early date, with the evolutionary ideas of independent
philosophical research. On the one hand, in the prevalent religious
teaching, we had the supernatural world, the miraculous, teleology:
on the other hand, in the nascent science of evolution, only
natural law, pure reason, mechanical causality. Every step that was
made by this science brought into greater relief its inconsistency
with the predominant religion.[1]
If we glance for a moment at the various fields in which the idea
of evolution is scientifically applied we find that, firstly,
the whole universe is conceived as a unity; secondly, our earth;
thirdly, organic life on the earth; fourthly, man, as its highest
product; and fifthly, the soul, as a special immaterial entity.
Thus we have, in historical succession, the evolutionary research
of cosmology, geology, biology, anthropology, and psychology.
The first comprehensive idea of cosmological evolution was put
forth by the famous critical philosopher Immanuel Kant, in 1755,
in the great work of his earlier years, _General Natural History
of the Heavens, or an Attempt to Conceive and to Explain the
Origin of the Universe mechanically, according to the Newtonian
Laws_. This remarkable work appeared anonymously, and was
dedicated to Frederick the Great, who, however, never saw it. It
was little noticed, and was soon entirely forgotten, until it
was exhumed ninety years afterwards by Alexander von Humboldt.
Note particularly that on the title-page stress is laid on the
_mechanical_ origin of the world and its explanation on Newtonian
principles; in this way the strictly Monistic character of the
whole cosmogony and the absolutely universal rule of natural law
are clearly expressed. It is true that Kant speaks much in it of
God and his wisdom and omnipotence; but this is limited to the
affirmation that God created once for all the unchangeable laws of
nature, and was henceforward bound by them and only able to work
through them. The Dualism which became so pronounced subsequently
in the philosopher of Koenigsberg counts for very little here.
The idea of a natural development of the world occurs in a clearer
and more consistent form, and is provided with a firm mathematical
basis, forty years afterwards, in the remarkable _Mécanique
Céleste_ of Pierre Laplace. His popular _Exposition du Système du
Monde_ (1796) destroyed at its roots the legend of creation that
had hitherto prevailed, or the Mosaic narrative in the Bible.
Laplace, who had become Minister of the Interior, Count, and
Chancellor of the Senate, under Napoleon, was merely honourable
and consistent when he replied to the emperor's question, "What
room there was for God in his system?": "Sire, I had no need
for that unfounded hypothesis." What strange ministers there
are sometimes![2] The shrewdness of the Church soon recognised
that the personal Creator was dethroned, and the creation-myth
destroyed, by this Monistic and now generally received theory
of cosmic development. Nevertheless it maintained towards it
the attitude which it had taken up 250 years earlier in regard
to the closely related and irrefutable system of Copernicus. It
endeavoured to conceal the truth as long as possible, or to oppose
it with Jesuitical methods, and finally it yielded. If the Churches
now silently admit the Copernican system and the cosmogony of
Laplace and have ceased to oppose them, we must attribute the fact,
partly to a feeling of their spiritual impotence, partly to an
astute calculation that the ignorant masses do not reflect on these
great problems.
In order to obtain a clear idea and a firm conviction of this
cosmic evolution by natural law, the eternal birth and death of
millions of suns and stars, one needs some mathematical training
and a lively imagination, as well as a certain competence in
astronomy and physics. The evolutionary process is much simpler,
and more readily grasped in geology. Every shower of rain or wave
of the sea, every volcanic eruption and every pebble, gives us a
direct proof of the changes that are constantly taking place on
the surface of our planet. However, the historical significance
of these changes was not properly appreciated until 1822, by Karl
von Hoff of Gotha, and modern geology was only founded in 1830
by Charles Lyell, who explained the whole origin and composition
of the solid crust of the earth, the formation of the mountains,
and the periods of the earth's development, in a connected system
by natural laws. From the immense thickness of the stratified
rocks, which contain the fossilised remains of extinct organisms,
we discovered the enormous length--running into millions of
years--of the periods during which these sedimentary rocks were
deposited in water. Even the duration of the _organic_ history of
the earth--that is to say, the period during which the plant and
animal population of our planet was developing--must itself be put
at more than a hundred million years. These results of geology and
paleontology destroyed the current legend of the six days' work of
a personal Creator. Many attempts were made, it is true, and are
still being made, to reconcile the Mosaic supernatural story of
creation with modern geology.[3] All these efforts of believers
are in vain. We may say, in fact, that it is precisely the study
of geology, the reflection it entails on the enormous periods of
evolution, and the habit of seeking the simple mechanical causes
of their constant changes, that contribute very considerably to
the advance of enlightenment. Yet in spite of this (or, possibly,
because of this), geological instruction is either greatly
neglected or entirely suppressed in most schools. It is certainly
eminently calculated (in connection with geography) to enlarge
the mind, and acquaint the child with the idea of evolution. An
educated person who knows the elements of geology will never
experience _ennui_. He will find everywhere in surrounding nature,
in the rocks and in the water, in the desert and on the mountains,
the most instructive stimuli to reflection.
The evolutionary process in organic nature is much more difficult
to grasp. Here we must distinguish two different series of
biological development, which have only been brought into proper
causal connection by means of our biogenetic law (1866); one series
is found in embryology (or ontogeny), the other in phylogeny (or
race-development). In Germany "evolution" always meant embryology,
or a part of the whole, until forty years ago. It stood for a
microscopic examination of the wonderful processes by means of
which the elaborate structure of the plant or animal body is
formed from the simple seed of the plant or the egg of the bird.
Until the beginning of the nineteenth century the erroneous
view was generally received that this marvellously complicated
structure existed, completely formed, in the simple ovum, and that
the various organs had merely to grow and to shape themselves
independently by a process of "evolution" (or unfolding), before
they entered into activity. An able German scientist, Caspar
Friedrich Wolff (son of a Berlin tailor), had already shown the
error of this "pre-formation theory" in 1759. He had proved, in his
dissertation for the doctorate, that no trace of the later body,
of its bones, muscles, nerves, and feathers, can be found in the
hen's egg (the commonest and most convenient object for study),
but merely a small round disk, consisting of two thin superimposed
layers. He had further showed that the various organs are only
built up gradually out of these simple elements, and that we can
trace, step by step, a series of real new growths. However, these
momentous discoveries, and the sound "theory of epigenesis" that
he based on them, were wholly ignored for fifty years, and even
rejected by the leading authorities. It was not until Oken had
re-discovered these important facts at Jena (1806), Pander had more
carefully distinguished the germinal layers (1817), and finally
Carl Ernst von Baer had happily combined observation and reflection
in his classical _Animal Embryology_ (1828), that embryology
attained the rank of an independent science with a sound empirical
base.
A little later it secured a well-merited recognition in botany
also, especially owing to the efforts of Matthias Schleiden of
Jena, the distinguished student who provided biology with a new
foundation in the "cell theory" (1838). But it was not until the
middle of the nineteenth century that people generally recognised
that the ovum of the plant or animal is itself only a simple cell,
and that the later tissues and organs gradually develop from this
"elementary organism" by a repeated cleavage of, and division of
labour in, the cells. The most important step was then made of
recognising that our human organism also develops from an ovum
(first discovered by Baer in 1827), in virtue of the same laws, and
that its embryonic development resembles that of the other mammals,
especially that of the ape. Each of us was, at the beginning of
his existence, a simple globule of protoplasm, surrounded by a
membrane, about 1/120 of an inch in diameter, with a firmer nucleus
inside it. These important embryological discoveries confirmed the
rational conception of the human organism that had been attained
much earlier by comparative anatomy: the conviction that the
human frame is built in the same way, and develops similarly from
a simple ovum, as the body of all other mammals. Even Linné had
already (1735) given man a place in the mammal class in his famous
_System of Nature_.
Differently from these embryological facts, which can be directly
observed, the phenomena of phylogeny (the development of species),
which are needed to set the former in their true light, are usually
outside the range of immediate observation. What was the origin of
the countless species of animals and plants? How can we explain the
remarkable relationships which unite similar species into genera
and these into classes? Linné answers the question very simply
with the belief in creation, relying on the generally accepted
Mosaic narrative: "There are as many different species of animals
and plants as there were different forms created by God in the
beginning." The first scientific answer was given in 1809 by the
great French scientist, Lamarck. He taught, in his suggestive
_Philosophie Zoologique_, that the resemblances in form and
structure of groups of species are due to real affinity, and that
all organisms descend from a few very simple primitive forms (or,
possibly, from a single one). These primitive forms were developed
out of lifeless matter by spontaneous generation. The resemblances
of related groups of species are explained by _inheritance_ from
common stem-forms; their dissimilarities are due to _adaptation_
to different environments, and to variety in the action of the
modifiable organs. The human race has arisen in the same way, by
transformation of a series of mammal ancestors, the nearest of
which are ape-like primates.
These great ideas of Lamarck, which threw light on the whole
field of organic life, and were closely approached by Goethe in
his own speculations, gave rise to the theory that we now know
as transformism, or the theory of evolution or descent. But the
far-seeing Lamarck was--as Caspar Friedrich Wolff had been fifty
years before--half a century before his time. His theory obtained
no recognition, and was soon wholly forgotten.
It was brought into the light once more in 1859 by the genius
of Charles Darwin, who had been born in the very year that the
_Philosophie Zoologique_ was published. The substance and the
success of his system, which has gone by the name of Darwinism
(in the wider sense) for forty-six years, are so generally known
that I need not dwell on them. I will only point out that the
great success of Darwin's epoch-making works is due to two causes:
firstly, to the fact that the English scientist most ingeniously
worked up the empirical material that had accumulated during
fifty years into a systematic proof of the theory of descent; and
secondly, to the fact that he gave it the support of a second
theory of his own, the theory of natural selection. This theory,
which gives a causal explanation of the transformation of species,
is what we ought to call "Darwinism" in the strict sense. We cannot
go here into the question how far this theory is justified, or how
far it is corrected by more recent theories, such as Weismann's
theory of germ-plasm (1844), or De Vries's theory of mutations
(1900). Our concern is rather with the unparalleled influence that
Darwinism, and its application to man, have had during the last
forty years on the whole province of science; and at the same time,
with its irreconcilable opposition to the dogmas of the Churches.
The extension of the theory of evolution to man was, naturally,
one of the most interesting and momentous applications of it. If
all other organisms arose, not by a miraculous creation, but by a
natural modification of earlier forms of life, the presumption is
that the human race also was developed by the transformation of the
most man-like mammals, the primates of Linné--the apes and lemurs.
This natural inference, which Lamarck had drawn in his simple way,
but Darwin had at first explicitly avoided, was first thoroughly
established by the gifted zoologist, Thomas Huxley, in his three
lectures on _Man's Place in Nature_ (1863). He showed that this
"question of questions" is unequivocally answered by three chief
witnesses--the natural history of the anthropoid apes, the anatomic
and embryological relations of man to the animals immediately
below him, and the recently discovered fossil human remains.
Darwin entirely accepted these conclusions of his friend eight
years afterwards, and, in his two-volume work, _The Descent of Man
and Sexual Selection_ (1871), furnished a number of new proofs in
support of the dreaded "descent of man from the ape." I myself
then (1874) completed the task I had begun in 1866, of determining
approximately the whole series of the extinct animal ancestors of
the human race, on the ground of comparative anatomy, embryology,
and paleontology. This attempt was improved, as our knowledge
advanced, in the five editions of my _Evolution of Man_. In the
last twenty years a vast literature on the subject has accumulated.
I must assume that you are acquainted with the contents of one
or other of these works, and will turn to the question, that
especially engages our attention at present, how the inevitable
struggle between these momentous achievements of modern science and
the dogmas of the Churches has run in recent years.
It was obvious that both the general theory of evolution and
its extension to man in particular must meet from the first
with the most determined resistance on the part of the Churches.
Both were in flagrant contradiction to the Mosaic story of
creation, and other Biblical dogmas that were involved in it,
and are still taught in our elementary schools. It is creditable
to the shrewdness of the theologians and their associates, the
metaphysicians, that they at once rejected Darwinism, and made a
particularly energetic resistance in their writings to its chief
consequence, the descent of man from the ape. This resistance
seemed the more justified and hopeful as, for seven or eight years
after Darwin's appearance, few biologists accepted his theory, and
the general attitude amongst them was one of cold scepticism. I can
well testify to this from my own experience. When I first openly
advocated Darwin's theory at a scientific congress at Stettin in
1863, I was almost alone, and was blamed by the great majority
for taking up seriously so fantastic a theory, "the dream of an
after-dinner nap," as the Göttinger zoologist, Keferstein, called
it.
The general attitude towards Nature fifty years ago was so
different from that we find everywhere to-day, that it is difficult
to convey a clear idea of it to a young scientist or philosopher.
The great question of creation, the problem how the various species
of plants and animals came into the world, and how man came into
being, did not exist yet in exact science. There was, in fact, no
question of it.
Seventy-seven years ago Alexander von Humboldt delivered, in this
very spot, the lectures which afterwards made up his famous
work, _Cosmos, the Elements of a Physical Description of the
World_. As he touched, in passing, the obscure problem of the
origin of the organic population of our planet, he could only say
resignedly: "The mysterious and unsolved problem of how things
came to be does not belong to the empirical province of objective
research, the description of what _is_." It is instructive to
find Johannes Müller, the greatest of German biologists in the
nineteenth century, speaking thus in 1852, in his famous essay,
"On the Generation of Snails in Holothurians": "The entrance of
various species of animals into creation is certain--it is a
fact of paleontology; but it is _supernatural_ as long as this
entrance cannot be perceived in the act and become an element of
observation." I myself had a number of remarkable conversations
with Müller, whom I put at the head of all my distinguished
teachers, in the summer of 1854. His lectures on comparative
anatomy and physiology--the most illuminating and stimulating I
ever heard--had captivated me to such an extent that I asked and
obtained his permission to make a closer study of the skeletons and
other preparations in his splendid museum of comparative anatomy
(then in the right wing of the buildings of the Berlin University),
and to draw them. Müller (then in his fifty-fourth year) used to
spend the Sunday afternoon alone in the museum. He would walk to
and fro for hours in the spacious rooms, his hands behind his
back, buried in thought about the mysterious affinities of the
vertebrates, the "holy enigma" of which was so forcibly impressed
by the row of skeletons. Now and again my great master would turn
to a small table at the side, at which I (a student of twenty
years) was sitting in the angle of a window, making conscientious
drawings of the skulls of mammals, reptiles, amphibians, and fishes.
I would then beg him to explain particularly difficult points in
anatomy, and once I ventured to put the question: "Must not all
these vertebrates, with their identity in internal skeleton, in
spite of all their external differences, have come originally from
a common form?" The great master nodded his head thoughtfully, and
said: "Ah, if we only knew that! If ever you solve that riddle,
you will have accomplished a supreme work." Two months afterwards,
in September, 1854, I had to accompany Müller to Heligoland, and
learned under his direction the beautiful and wonderful inhabitants
of the sea. As we fished together in the sea, and caught the lovely
medusæ, I asked him how it was possible to explain their remarkable
alternation of generations; if the medusæ, from the ova of which
polyps develop to-day, must not have come originally from the more
simply organised polyps? To this precocious question, I received
the same resigned answer: "Ah, that is a very obscure problem! We
know nothing whatever about the origin of species."
Johannes Müller was certainly one of the greatest scientists of the
nineteenth century. He takes rank with Cuvier, Baer, Lamarck, and
Darwin. His insight was profound and penetrating, his philosophic
judgment comprehensive, and his mastery of the vast province
of biology was enormous. Emil du Bois-Reymond happily compared
him, in his fine commemorative address, to Alexander the Great,
whose kingdom was divided into several independent realms at his
death. In his lectures and works Müller treated no less than four
different subjects, for which four separate chairs were founded
after his death in 1858--human anatomy, physiology, pathological
anatomy, and comparative anatomy. In fact, we ought really to add
two more subjects--zoology and embryology. Of these, also, we
learned more from Müller's classic lectures than from the official
lectures of the professors of those subjects. The great master died
in 1858, a few months before Charles Darwin and Alfred R. Wallace
made their first communications on their new theory of selection
in the Journal of the Linnæan Society. I do not doubt in the least
that this surprising answer of the riddle of creation would have
profoundly moved Müller, and have been fully admitted by him on
mature reflection.
To these leading masters in biology, and to all other anatomists,
physiologists, zoologists, and botanists up to 1858, the question
of organic creation was an unsolved problem; the great majority
regarded it as insoluble. The theologians and their allies, the
metaphysicians, built triumphantly on this fact. It afforded a
clear proof of the limitations of reason and science. A miracle
only could account for the origin of these ingenious and carefully
designed organisms; nothing less than the Divine wisdom and
omnipotence could have brought man into being. But this general
resignation of reason, and the dominance of supernatural ideas
which it encouraged, were somewhat paradoxical in the thirty years
between Lyell and Darwin, between 1830 and 1859, since the natural
evolution of the earth, as conceived by the great geologist, had
come to be universally recognised. Since the earlier of these dates
the iron necessity of natural law had ruled in inorganic nature,
in the formation of the mountains and the movement of the heavenly
bodies. In organic nature, on the contrary, in the creation and the
life of animals and plants, people saw only the wisdom and power of
an intelligent Creator and Controller; in other words, everything
was ruled by mechanical causality in the inorganic world, but by
teleological finality in the realm of biology.
Philosophy, strictly so called, paid little or no attention to
this dilemma. Absorbed almost exclusively in metaphysical and
dialectical speculations, it looked with supreme contempt or
indifference on the enormous progress that the empirical sciences
were making. It affected, in its character of "purely mental
science," to build up the world out of its own head, and to have no
need of the splendid material that was being laboriously gathered
by observation and experiment. This is especially true of Germany,
where Hegel's system of "absolute idealism" had secured the highest
regard, particularly since it had been made obligatory as "the
royal State-philosophy of Prussia"--mainly because, according to
Hegel, "in the State the Divine will itself and the monarchical
constitution alone represent the development of reason; all
other forms of constitution are lower stages of the development
of reason." Hegel's abstruse metaphysics has also been greatly
appreciated because it has made so thorough and consistent a use
of the idea of evolution. But this pretended "evolution of reason"
floated far above real nature in the pure ether of the absolute
spirit, and was devoid of all the material ballast that the
empirical science of the evolution of the world, the earth, and its
living population, had meantime accumulated. Moreover, it is well
known how Hegel himself declared, with humorous resignation, that
only _one_ of his many pupils had understood him, and this one had
misunderstood him.
From the higher standpoint of general culture the difficult
question forces itself on us: What is the real value of the idea
of evolution in the whole realm of science? We are bound to
answer that it varies considerably. The facts of the evolution of
the individual, or of ontogeny, were easy to observe and grasp:
the evolution of the crust of the earth and of the mountains in
geology seemed to have an equally sound empirical foundation; the
physical evolution of the universe seemed to be established by
mathematical speculation. There was no longer any serious question
of _creation_, in the literal sense, of the deliberate action
of a personal Creator, in these great provinces. But this made
people cling to the idea more than ever in regard to the origin of
the countless species of animals and plants, and especially the
creation of man. This transcendental problem seemed to be entirely
beyond the range of natural development; and the same was thought
of the question of the nature and origin of the soul, the mystic
entity that was appropriated by metaphysical speculation as its
subject. Charles Darwin suddenly brought a clear light into this
dark chaos of contradictory notions in 1859. His epoch-making work,
_The Origin of Species_, proved convincingly that this historical
process is not a supernatural mystery, but a physiological
phenomenon; and that the preservation of improved races in the
struggle for life had produced, by a natural evolution, the whole
wondrous world of organic life.
To-day, when evolution is almost universally recognised in biology,
when thousands of anatomic and physiological works are based on
it every year, the new generation can hardly form an idea of the
violent resistance that was offered to Darwin's theory and the
impassioned struggles it provoked. In the first place, the Churches
at once raised a vigorous protest; they rightly regarded their
new antagonist as the deadly enemy of the legend of creation,
and saw the very foundations of their creed threatened. The
Churches found a powerful ally in the dualistic metaphysics that
still claims to represent the real "idealist philosophy" at most
universities. But most dangerous of all to the young theory
was the violent resistance it met almost everywhere in its own
province of empirical science. The prevailing belief in the fixity
and the independent creation of the various species was much more
seriously menaced by Darwin's theory than it had been by Lamarck's
transformism. Lamarck had said substantially the same thing fifty
years before, but had failed to convince through the lack of
effective evidence. Many scientists, some of great distinction,
opposed Darwin because either they had not an adequate acquaintance
with the whole field of biology, or it seemed to them that his bold
speculation advanced too far from the secure base of experience.
When Darwin's work appeared in 1859, and fell like a flash of
lightning on the dark world of official biology, I was engaged in a
scientific expedition to Sicily and taken up with a thorough study
of the graceful radiolarians, those wonderful microscopic marine
animals that surpass all other organisms in the beauty and variety
of their forms. The special study of this remarkable class of
animals, of which I afterwards described more than 4,000 species,
after more than ten years of research, provided me with one of the
solid foundation-stones of my Darwinian ideas. But when I returned
from Messina to Berlin in the spring of 1860, I knew nothing as yet
of Darwin's achievement. I merely heard from my friends at Berlin
that a remarkable work by a crazy Englishman had attracted great
attention, and that it turned upside down all previous ideas as to
the origin of species.
I soon perceived that almost all the experts at Berlin--chief
amongst them were the famous microscopist, Ehrenberg; the
anatomist, Reichert; the zoologist, Peters; and the geologist,
Beyrich--were unanimous in their condemnation of Darwin. The
brilliant orator of the Berlin Academy, Emil du Bois-Reymond,
hesitated. He recognised that the theory of evolution was
the only natural solution of the problem of creation; but he
laughed at the application of it as a poor romance, and declared
that the phylogenetic inquiries into the relationship of the
various species had about as much value as the research of
philologists into the genealogical tree of the Homeric heroes.
The distinguished botanist, Alexander Braun, stood quite alone
in his full and warm assent to the theory of evolution. I found
comfort and encouragement with this dear and respected teacher,
when I was deeply moved by the first reading of Darwin's book,
and soon completely converted to his views. In Darwin's great and
harmonious conception of Nature, and his convincing establishment
of evolution, I had an answer to all the doubts that had beset me
since the beginning of my biological studies.
My famous teacher, Rudolf Virchow, whom I had met at Würtzburg in
1852, and was soon associated with in the most friendly relations
as special pupil and admiring assistant, played a very curious
part in this great controversy. I am, I think, one of those
elderly men who have followed Virchow's development, as man and
thinker, with the greatest interest during the last fifty years.
I distinguish three periods in his psychological metamorphoses.
In the first decade of his academic life, from 1847 to 1858,
mainly at Würtzburg, he effected the great reform of medicine that
culminated brilliantly in his cellular pathology. In the following
twenty years (1858-1877) he was chiefly occupied with politics
and anthropology. He was at first favourable to Darwinism, then
sceptical, and finally rejected it. His powerful and determined
opposition to it dates from 1877, when, in is famous speech on "The
Freedom of Science in the Modern State," he struck a heavy blow
at that freedom, denounced the theory of evolution as dangerous
to the State, and demanded its exclusion from the schools. This
remarkable metamorphosis is so important, and has had so much
influence, yet has been so erroneously described, that I will
deal with it somewhat fully in the next chapter, especially as
I have then to treat one chief problem, the descent of man from
the ape. For the moment, I will merely recall the fact that in
Berlin, the "metropolis of intelligence," as it has been called,
the theory of evolution, now generally accepted, met with a more
stubborn resistance than in most of our other leading educational
centres, and that this opposition was due above all to the powerful
authority of Virchow.
We can only glance briefly here at the victorious struggle that
the idea of evolution has conducted in the last three decades of
the nineteenth century. The violent resistance that Darwinism
encountered nearly everywhere in its early years was paralysed
towards the end of the first decade. In the years 1866-1874 many
works were published in which not only were the foundations of the
theory scientifically strengthened, but its general recognition
was secured by popular treatment of the subject. I made the first
attempt in 1866, in my _General Morphology_, to present connectedly
the whole subject of evolution and make it the foundation of a
consistent Monistic philosophy; and I then gave a popular summary
of my chief conclusions in the ten editions of my _History of
Creation_. In my _Evolution of Man_ I made the first attempt to
apply the principles of evolution thoroughly and consistently to
man, and to draw up a hypothetical list of his animal ancestors.
The three volumes of my _Systematic Phylogeny_ (1894-1896)
contain a fuller outline of a natural classification of organisms
on the basis of their stem-history. There have been important
contributions to the science of evolution in all its branches in
the Darwinian periodical, _Cosmos_, since 1877; and a number of
admirable popular works helped to spread the system.
However, the most important and most welcome advance was made by
science when, in the last thirty years, the idea of evolution
penetrated into every branch of biology, and was recognised as
fundamental and indispensable. Thousands of new discoveries and
observations in all sections of botany, zoology, protistology,
and anthropology, were brought forward as empirical evidence of
evolution. This is especially true of the remarkable progress of
paleontology, comparative anatomy, and embryology, but it applies
also to physiology, chorology (the science of the distribution
of living things), and œcology (the description of the habits of
animals). How much our horizon was extended by these, and how
much the unity of our Monistic system gained, can be seen in any
modern manual of biology. If we compare them with those that gave
us extracts of natural history forty or fifty years ago, we see
at once what an enormous advance has taken place. Even the more
remote branches of anthropological science, ethnography, sociology,
ethics, and jurisprudence, are entering into closer relations with
the theory of evolution, and can no longer escape its influence. In
view of all this, it is ridiculous for theological and metaphysical
journals to talk, as they do, of the failure of evolution and "the
death-bed of Darwinism."
Our science of evolution won its greatest triumph when, at the
beginning of the twentieth century, its most powerful opponents,
the Churches, became reconciled to it, and endeavoured to bring
their dogmas into line with it. A number of timid attempts to
do so had been made in the preceding ten years by different
free-thinking theologians and philosophers, but without much
success. The distinction of accomplishing this in a comprehensive
and well-informed manner was reserved for a Jesuit, Father Erich
Wasmann of Luxemburg. This able and learned entomologist had
already earned some recognition in zoology by a series of admirable
observations on the life of ants, and the captives that they
always keep in their homes, certain very small insects which have
themselves been curiously modified by adaptation to their peculiar
environment. He showed that these striking modifications can only
be rationally explained by descent from other free-living species
of insects. The various papers in which Wasmann gave a thoroughly
Darwinian explanation of the biological phenomena first appeared
(1901-1903) in the Catholic periodical, _Stimmen aus Maria-Laach_,
and are now collected in a special work entitled, _Modern Biology
and the Theory of Evolution_.
This remarkable book of Wasmann's is a masterpiece of Jesuitical
sophistry. It really consists of three entirely different sections.
The first third gives, in the introduction, what is, for Catholics,
a clear and instructive account of modern biology, especially the
cell-theory, and the theory of evolution (chapters i.-viii.). The
second third, the ninth chapter, is the most valuable part of the
work. It has the title: "The Theory of Fixity or the theory of
Evolution?" Here the learned entomologist gives an interesting
account of the results of his prolonged studies of the morphology
and the œcology of the ants and their captives, the myrmecophilæ.
He shows impartially and convincingly that these complicated and
remarkable phenomena can only be explained by evolution, and that
the older doctrine of the fixity and independent creation of the
various species is quite untenable. With a few changes this ninth
chapter could figure as a useful part of a work by Darwin or
Weismann or some other evolutionist. The succeeding chapter (the
last third) is flagrantly inconsistent with the ninth. It deals
most absurdly with the application of the theory of evolution to
man. The reader has to ask himself whether Wasmann really believes
these confused and ridiculous notions, or whether he merely aims at
befogging his readers, and so preparing the way for the acceptance
of the conventional creed.
Wasmann's book has been well criticised by a number of competent
students, especially by Escherich and Francé. While fully
recognising his great services, they insist very strongly on
the great mischief wrought by this smuggling of the Jesuitical
spirit into biology. Escherich points out at length the glaring
inconsistencies and the obvious untruths of this "ecclesiastical
evolution." He summarises his criticism in the words: "If the
theory of evolution can really be reconciled with the dogmas of the
Church only in the way we find here, Wasmann has clearly proved
that any such reconciliation is impossible. Because what Wasmann
gives here as the theory of evolution is a thing mutilated beyond
recognition and incapable of any vitality." He tries, like a good
Jesuit, to prove that it does not tend to undermine, but to give a
firm foundation to, the story of supernatural creation, and that it
was really not Lamarck and Darwin, but St. Augustin and St. Thomas
of Aquin, who founded the science of evolution. "God does not
interfere directly in the order of Nature when he can act by means
of natural causes." Man alone constitutes a remarkable exception;
because "the human soul, being a spiritual entity, cannot be
derived from matter even by the Divine omnipotence, like the vital
forms of the plants and animals" (p. 299).
In an instructive article on "Jesuitical Science" (in the Frankfort
_Freie Wort_, No. 22, 1904), R. H. Francé gives an interesting
list of the prominent Jesuits who are now at work in the various
branches of science. As he rightly says, the danger consists "in
a systematic introduction of the Jesuitical spirit into science,
a persistent perversion of all its problems and solutions, and an
astute undermining of its foundations; to speak more precisely,
the danger is that people are not sufficiently conscious of it,
and that they, and even science itself, fall into the cleverly
prepared pit of believing that there is such a thing as _Jesuitical
science_, the results of which may be taken seriously."[4]
While fully recognising these dangers, I nevertheless feel that the
Jesuit Father Wasmann, and his colleagues, have--unwittingly--done
a very great service to the progress of pure science. The Catholic
Church, the most powerful and widespread of the Christian sects,
sees itself compelled to capitulate to the idea of evolution. It
embraces the most important application of the idea, Lamarck and
Darwin's theory of descent, which it had vigorously combated until
twenty years ago. It does, indeed, mutilate the great tree, cutting
off its roots and its highest branch; it rejects spontaneous
generation or archigony at the bottom, and the descent of man
from animal ancestors above. But these exceptions will not last.
Impartial biology will take no notice of them, and the religious
creed will at length determine that the more complex species have
been evolved from a series of simpler forms according to Darwinian
principles. The belief in a supernatural creation is restricted
to the production of the earliest and simplest stem-forms, from
which the "natural species" have taken their origin; Wasmann gives
that name to all species that are demonstrably descended from a
common stem-form; in other words, to what other classifiers call
"stems" or "phyla." The 4,000 species of ants in his system, which
he believes to be genetically related, are comprised by him in
one "natural species." On the other hand, man forms one isolated
"natural species" for himself, without any connection with the
other mammals.
The Jesuitical sophistry that Wasmann betrays in this ingenious
distinction between "systematic and natural species" is also
found in his philosophic "Thoughts on Evolution" (chap. viii.),
his distinction between philosophic and scientific evolution,
or between evolution in one stem and in several stems. His
remarks (in chap. vii.) on "the cell and spontaneous generation"
are similarly marred by sophistry. The question of spontaneous
generation or archigony--that is to say, of the first appearance of
organic life on the earth, is one of the most difficult problems
in biology, one of those in which the most distinguished students
betray a striking weakness of judgment. Dr. Heinrich Schmidt, of
Jena, has lately written an able and popular little work on that
subject. In his _Spontaneous Generation and Professor Reinke_
(1903), he has shown to what absurd consequences the ecclesiastical
ideas lead on this very question. The botanist Reinke, of Kiel,
is now regarded amongst religious people as the chief opponent of
Darwinism; for many conservatives this is because he is a member
of the Prussian Herrenhaus (a very intelligent body, of course!).
Although he is a strong evangelical, many of his mystic deductions
agree surprisingly with the Catholic speculations of Father
Wasmann. This is especially the case with regard to spontaneous
generation. They both declare that the first appearance of life
must be traced to a miracle, to the work of a personal deity,
whom Reinke calls the "cosmic intelligence." I have shown the
unscientific character of these notions in my last two works,
_The Riddle of the Universe_, and _The Wonders of Life_. I have
drawn attention especially to the widely distributed monera of the
chromacea class--organisms of the simplest type conceivable, whose
whole body is merely an unnucleated, green, structureless globule
of plasm (Chroococcus); their whole vital activity consists of
growth (by forming plasm) and multiplication (by dividing into
two). There is little theoretical difficulty in conceiving the
origin of these new simple monera from inorganic compounds of
albumen, or their later transformation into the simplest nucleated
cells. All this, and a good deal more that will not fit in his
Jesuitical frame, is shrewdly ignored by Wasmann.
In view of the great influence that Catholicism still has on public
life in Germany, through the Centre party, this change of front
should be a great gain to education. Virchow demanded as late as
1877 that the dangerous doctrine of evolution should be excluded
from the schools. The Ministers of Instruction of the two chief
German States gratefully adopted this warning from the leader of
the progressive party, forbade the teaching of Darwinian ideas,
and made every effort to check the spread of biological knowledge.
Now, twenty-five years afterwards, the Jesuits come forward, and
demand the opposite. They recognise openly that the hated theory of
evolution is established, and try to reconcile it with the creed!
What an irony of history! And we find much the same story when we
read the struggles for freedom of thought and for the recognition
of evolution in the other educated countries of Europe.
In Italy, its cradle and home, educated people generally look
upon the papacy with the most profound disdain. I have spent many
years in Italy, and have never met an educated Italian of such
bigoted and narrow views as we usually find amongst educated
German Catholics--represented with success in the Reichstag by the
Centre party. It is proof enough of the reactionary character of
German Catholics that the Pope himself describes them as his most
vigorous soldiers, and points them out as models to the faithful
of other nations. As the whole history of the Roman Church shows,
the charlatan of the Vatican is the deadly enemy of free science
and free teaching. The present German Emperor ought to regard it as
his most sacred duty to maintain the tradition of the Reformation,
and to promote the formation of the German people in the sense
of Frederick the Great. Instead of this we have to look on with
heavy hearts while the Emperor, badly advised and misled by those
in influence about him, suffers himself to be caught closer and
closer in the net of the Catholic clergy, and sacrifices to it
the intelligence of the rising generation. In September, 1904,
the Catholic journals announced triumphantly that the adoption of
Catholicism by the Emperor and his Chancellor was close at hand.[5]
The firmness of the belief in conventional dogmas, which hampers
the progress of rational enlightenment in orthodox Protestant
circles as well as Catholic, is often admired as an expression of
the deep emotion of the German people. But its real source is their
confusion of thought and their credulity, the power of conservative
tradition, and the reactionary state of political education. While
our schools are bent under the yoke of the creeds, those of our
neighbours are free. France, the pious daughter of the Church,
gives anxious moments to her ambitious mother. She is breaking the
chains of the Concordat, and taking up the work of the Reformation.
In Germany, the birthplace of the Reformation, the Reichstag and
the Government vie with each other in smoothing the paths for the
Jesuits, and fostering, instead of suppressing, the intolerant
spirit of the sectarian school. Let us hope that the latest episode
in the history of evolution, its recognition by Jesuitical science,
will bring about the reverse of what they intend--the substitution
of rational science for blind faith.
CHAPTER II
THE STRUGGLE OVER OUR GENEALOGICAL TREE
OUR APE-RELATIVES AND THE VERTEBRATE-STEM
EXPLANATION OF PLATE II
SKELETONS OF FIVE ANTHROPOID APES
These skeletons of the five living genera of anthropomorpha
are reduced to a common size, in order to show better the
relative proportions of the various parts. The human skeleton
is 1/20th natural size, the gorilla 1/18th, the chimpanzee
1/7th, the orang 1/7th, the gibbon 1/9th. Young specimens of
the chimpanzee and orang have been selected, because they
approach nearer to man than the adult. No one of the living
anthropoid apes is nearest to man in all respects; this cannot
be said of either of the African (gorilla and chimpanzee) or
the Asiatic (orang and gibbon). This anatomic fact is explained
phylogenetically on the ground that none of them are direct
ancestors of man; they represent divergent branches of the
stem, of which man is the crown. However, the small gibbon is
nearest related to the hypothetical common ancestor of all the
anthropomorpha to which we give the name of Prothylobates.
Further information will be found in my _Last Link_ and
_Evolution of Man_ (chap. xxiii.).
PLATE II.
SKELETONS OF FIVE ANTHROPOID APES.
[Illustration:
1/20 MAN (Homo)
1/18 GORILLA
1/7 Young CHIMPANZEE (Anthropithecus)
1/7 Young ORANG (Satyrus)
1/9 GIBBON (Hylobates)]
CHAPTER II
THE STRUGGLE OVER OUR GENEALOGICAL TREE
OUR APE-RELATIVES AND THE VERTEBRATE-STEM
In the previous chapter I tried to give you a general idea of
the present state of the controversy in regard to evolution.
Comparing the various branches of thought we found that the older
mythological ideas of the creation of the world were driven long
ago out of the province of inorganic science, but that they did
not yield to the rational conception of natural development until
a much later date in the field of organic nature. Here the idea of
evolution did not prove completely victorious until the beginning
of the twentieth century, when its most zealous and dangerous
opponent, the Church, was forced to admit it. Hence the open
acknowledgment of the Jesuit, Father Wasmann, deserves careful
attention, and we may look forward to a further development. If his
force of conviction and his moral courage are strong enough, he
will go on to draw the normal conclusions from his high scientific
attainments and leave the Catholic Church, as the prominent
Jesuits, Count Hoensbroech and the able geologist, Professor Renard
of Ghent, one of the workers on the deep-sea deposits in the
_Challenger_ expedition, have lately done. But even if this does
not happen, his recognition of Darwinism, in the name of Christian
belief, will remain a landmark in the history of evolution. His
ingenious and very Jesuitical attempt to bring together the
opposite poles will have no very mischievous effect; it will
rather tend to hasten the victory of the scientific conception of
evolution over the mystic beliefs of the Churches.
You will see this more clearly if we go on to consider the
important special problem of the "descent of man from the ape,"
and its irreconcilability with the conventional belief that God
made man according to His own image. That this ape or pithecoid
theory is an irresistible deduction from the general principle
of evolution was clearly recognised forty-five years ago, when
Darwin's work appeared, by the shrewd and vigilant theologians;
it was precisely in this fact that they found their strongest
motive for vigorous resistance. It is quite clear. _Either_ man
was brought into existence, like the other animals, by a special
creative act, as Moses and Linné taught (an "embodied idea of the
Creator," as the famous Agassiz put it so late as 1858); _or_ he
has been developed naturally from a series of mammal ancestors, as
is claimed by the systems of Lamarck and Darwin.
In view of the very great importance of this pithecoid theory,
we will first cast a brief glance at its founders and then
summarise the proofs in support of it. The famous French biologist,
Jean Lamarck, was the first scientist definitely to affirm the
descent of man from the ape and seek to give scientific proof
of it. In his splendid work, fifty years in advance of his time,
the _Philosophie Zoologique_ (1809), he clearly traced the
modifications and advances that must have taken place in the
transformation of the man-like apes (the primate forms similar to
the orang and the chimpanzee); the adaptation to walking upright,
the consequent modification of the hands and feet, and later,
the formation of speech and the attainment of a higher degree of
intelligence. Lamarck's remarkable theory, and this important
consequence of it, soon fell into oblivion. When Darwin brought
evolution to the front again fifty years afterwards, he paid no
attention to the special conclusion. He was content to make the
following brief prophetic observation in his work: "Light will be
thrown on the origin and the history of man." Even this innocent
remark seemed so momentous to the first German translator of the
work, Bronn, that he suppressed it. When Darwin was asked by
Wallace whether he would not go more fully into it, he replied: "I
think of avoiding the whole subject, as it is so much involved in
prejudice; though I quite admit that it is the highest and most
interesting problem for the thinker."
The first thorough works of importance on the subject appeared
in 1863. Thomas Huxley in England, and Carl Vogt in Germany,
endeavoured to show that the descent of man from the ape was a
necessary consequence of Darwinism, and to provide an empirical
base for the theory by every available argument. Huxley's work
on _Man's Place in Nature_ was particularly valuable. He first
gave convincingly, in three lectures, the empirical evidence on
the subject--the natural history of the anthropoid apes, the
anatomical and embryological relations of man to the next lowest
animals, and the recently discovered fossil human remains. I then
(1866) made the first attempt to establish the theory of evolution
comprehensively by research in anatomy and embryology, and to
determine the chief stages in the natural classification of the
vertebrates that must have been passed through by our earlier
vertebrate ancestors. Anthropology thus becomes a part of zoology.
In my _History of Creation_ I further developed these early
evolutionary sketches, and improvements were made in the successive
editions.
In the meantime, the great master, Darwin, had decided to deal
with this chief evolutionary problem in a special work. The two
volumes of his _Descent of Man_ appeared in 1871. They contained an
able discussion of sexual selection, or the selective influence of
sexual love and high psychic activities connected therewith, and
their significance in regard to the origin of man. As this part of
Darwin's work was afterwards attacked with particular virulence, I
will say that, in my opinion, it is of the greatest importance, not
only for the general theory of evolution, but also for psychology,
anthropology, and æsthetics.
My own feeble early efforts (1866), not only to establish the
descent of man from the nearest related apes, but also to determine
more precisely the long series of our earlier and lower vertebrate
ancestors, had not at all satisfied me. In particular, I had had to
leave unanswered in my _General Morphology_ the very interesting
question: from which invertebrate animals the vertebrate stem
originally came. A clear and unexpected light was thrown on it some
time afterwards by the astounding discoveries of Kowalevsky, which
revealed an essential agreement in embryonic development between
the lowest vertebrate (Amphioxus) and a lowly tunicate (Ascidia).
In the succeeding years, the numerous discoveries in connection
with the formation of the germinal layers in different animals so
much enlarged our embryological outlook that I was able to prove
the complete homology of the two-layered _gastrula_ (a cup-shaped
embryonic form) in all the tissue-forming animals (_metazoa_) in
my _Monograph on the Sponges_. From this I inferred, in virtue of
the biogenetic law, the common descent of all the metazoa from
one and the same gastrula-shaped stem-form, the _gastræa_. This
hypothetical stem-form, to which man's earliest multicellular
ancestors also belong, was afterwards proved by Monticelli's
observations to be still in existence. The evolution of these
very simple tissue-forming animals from still simpler unicellular
forms (_protozoa_) is shown by the corresponding processes that
we witness in what is called the segmentation of the ovum or
gastrulation, in the development of the two-layered germ from the
single cell of the ovum.
Encouraged by these great advances of modern phylogeny, and with
the support of many new discoveries in comparative anatomy and
embryology, in which a number of distinguished observers were at
work, I was able in 1874 to venture on the first attempt to trace
continuously the whole story of man's evolution. In doing so, I
took my stand on the firm ground of the biogenetic law, seeking
to give a phylogenetic cause for each fact of embryology. My
_Evolution of Man_, which made the first attempt to accomplish this
difficult task, was materially improved and enlarged as new and
important discoveries were made. The latest edition (1903 [1904 in
English]) contains thirty chapters distributed in two volumes, the
first of which deals with embryology (or ontogeny), and the second
with the development of species (or phylogeny).
Though I was quite conscious that there were bound to be gaps
and weak points in these first attempts to frame a natural
anthropogeny, I had hoped they would have some influence on
modern anthropology, and especially that the first sketches of a
genealogical tree of the animal world would prove a stimulus to
fresh research and improvement. In this I was much mistaken. The
dominant school of anthropology, especially in Germany, declined to
suffer the introduction of the theory of evolution, declaring it to
be an unfounded hypothesis, and described our carefully prepared
ancestral trees as mere figments. This was due, in the first place,
to the great authority of the founder and president (for many
years) of the German Anthropological Society, Rudolf Virchow, as I
briefly pointed out in the previous chapter. In view of the great
regard that is felt for this distinguished scientist, and the
extent to which his powerful opposition prevented the spread of the
theory, it is necessary to deal more fully with his position on the
subject. I am still further constrained to do this because of the
erroneous views of it that are circulating, and my own fifty years'
acquaintance with my eminent teacher enables me to put them right.
Not one of Virchow's numerous pupils and friends can appreciate
more than I do his real services to medical science. His _Cellular
Pathology_ (1858), his thorough application of the cell-theory to
the science of disease, is, in my opinion, one of the greatest
advances made by modern medicine. I had the good fortune to
begin my medical studies at Würzburg in 1852, and to spend six
valuable terms under the personal guidance of four biologists of
the first rank--Albert Kölliker, Rudolf Virchow, Franz Leydig
and Carl Gegenbaur. The great stimulus that I received from
these distinguished masters in every branch of comparative and
microscopic biology was the starting-point of my whole training
in that science, and enabled me subsequently to follow with ease
the higher intellectual flight of Johannes Müller. From Virchow
especially I learned, not only the analytic art of careful
observation and judicious appreciation of the detailed facts of
anatomy, but also the synthetic conception of the whole human
frame, the profound conviction of the _unity_ of our nature, the
inseparable connection of body and mind, to which Virchow gave a
fine expression in his classic essay on "The Efforts to bring about
Unity in Scientific Medicine" (1849). The leading articles which
he wrote at that time for the Journal of Pathological Anatomy and
Physiology, which he had founded, contain much new insight into the
wonders of life, and a number of excellent general reflections on
their significance--pregnant ideas that we can make direct use of
for Monistic purposes. In the controversy that broke out between
empirical rationalism and materialism and the older vitalism and
mysticism, he took the side of the former, and fought together
with Jacob Moleschott, Carl Vogt, and Ludwig Büchner. I owe the
firm conviction of the unity of organic and inorganic nature, of
the mechanical character of all vital and psychic activity, which
I have always held to be the foundation of my Monistic system,
in a great measure to Virchow's teaching and the exhaustive
conversations I had with him when I was his assistant. The profound
views of the nature of the cell and the independent individuality
of these elementary organisms, which he advanced in his great
work _Cellular Pathology_, remained guiding principles for me in
the prolonged studies that I made thirty years afterwards of the
organisation of the radiolaria and other unicellular protists;
and also in regard to the theory of the cell-soul, which followed
naturally from the psychological study of it.
His life at Würtzburg was the most brilliant period of Virchow's
indefatigable scientific labours. A change took place when he
removed to Berlin in 1856. He then occupied himself chiefly with
political and social and civic interests. In the last respect
he has done so much for Berlin and the welfare of the German
people that I need not enlarge on it. Nor will I go into his
self-sacrificing and often thankless political work as leader of
the progressive party; there are differences of opinion as to its
value. But we must carefully examine his peculiar attitude towards
evolution, and especially its chief application, the ape-theory.
He was at first favourable to it, then sceptical, and finally
decidedly hostile.
When the Lamarckian theory was brought to light again by Darwin in
1859, many thought that it was Virchow's vocation to take the lead
in defending it. He had made a thorough study of the problem of
heredity; he had realised the power of adaptation through his study
of pathological changes; and he had been directed to the great
question of the origin of man by his anthropological studies. He
was at that time regarded as a determined opponent of all dogmas;
he combated transcendentalism either in the form of ecclesiastical
creeds or anthropomorphism. After 1862 he declared that "the
possibility of a transition from species to species was a necessity
of science." When I opened the first public discussion of Darwinism
at the Stettin scientific congress in 1863, Virchow and Alexander
Braun were among the few scientists who would admit the subject
to be important and deserving of the most careful study. When I
sent to him in 1865 two lectures that I had delivered at Jena on
the origin and genealogical tree of the human race, he willingly
received them amongst his _Collection of Popular Scientific
Lectures_. In the course of many long conversations I had with
him on the matter, he agreed with me in the main, though with the
prudent reserve and cool scepticism that characterised him. He
adopts the same moderate attitude in the lecture that he delivered
to the Artisans' Union at Berlin in 1869 on "Human and Ape Skulls."
His position definitely changed in regard to Darwinism from 1877
onward. At the Scientific Congress that was then held at Munich I
had, at the pressing request of my Munich friends, undertaken the
first address (on 18th September) on "Modern Evolution in Relation
to the whole of Science." In this address I had substantially
advanced the same general views that I afterwards enlarged in my
_Monism_, _Riddle of the Universe_, and _Wonders of Life_. In the
ultramontane capital of Bavaria, in sight of a great university
which emphatically describes itself as Catholic, it was somewhat
bold to make such a confession of faith. The deep impression that
it had made was indicated by the lively manifestations of assent on
the one hand, and displeasure on the other, that were at once made
in the Congress itself and in the Press. On the following day I
departed for Italy (according to an arrangement made long before).
Virchow did not come to Munich until two days afterwards, when he
delivered (on 22nd September, in response to entreaties from people
of position and influence) his famous antagonistic speech on "The
Freedom of Science in the Modern State." The gist of the speech
was that this freedom ought to be restricted; that evolution is
an unproved hypothesis, and ought not to be taught in the school
because it is dangerous to the State: "We must not teach," he said,
"that man descends from the ape or any other animal." In 1849, the
young Monist, Virchow, had emphatically declared this conviction,
"that he would never be induced to deny the thesis of the unity
of human nature and its consequences"; now, twenty-eight years
afterwards, the prudent Dualistic politician entirely denied it.
He had formerly taught that all the bodily and mental processes in
the human organism depend on the mechanism of the cell-life; now
he declared the soul to be a special immaterial entity. But the
crowning feature of this reactionary speech was his compromise with
the Church, which he had fought so vigorously twenty years before.
The character of Virchow's speech at Munich is best seen in the
delight with which it was at once received by the reactionary and
clerical papers, and the profound concern of all Liberal journals,
either in the political or the religious sense. When Darwin read
the English translation of the speech he--generally so gentle in
his judgments--wrote: "Virchow's conduct is shameful, and I hope he
will some day feel the shame." In 1878, I made a full reply to it
in my _Free Science and Free Teaching_, in which I collected the
most important press opinions on the matter.[6]
From this very decided turn at Munich until his death, twenty-five
years afterwards, Virchow was an indefatigable and very influential
opponent of evolution. In his annual appearances at congresses he
has always contested it, and has obstinately clung to his statement
that "it is quite certain that man does not descend from the ape or
any other animal." To the question: "Whence does he come, then?"
he had no answer, and retired to the resigned position of the
Agnostic, which was common before Darwin's time: "We do not know
how life arose, and how the various species came into the world."
His son-in-law, Professor Rabl, has tried to draw attention once
more to his earlier conception, and has declared that even in
later years Virchow often recognised the truth of evolution in
private conversation. This only makes it the more regrettable that
he always said the contrary in public. The fact remains that ever
since the opponents of evolution, especially the reactionaries and
clericals, have appealed to the authority of Virchow.
The wholly reactionary system that this led to has been well
described by Robert Drill (1902) in his _Virchow as a Reactionary_.
How little qualified the great pathologist was to appreciate the
scientific bases of the pithecoid theory is clear from the absurd
statement he made, in the opening speech of the Vienna Congress
of Anthropologists, in 1894, that man might just as well be
claimed to descend from a sheep or an elephant as from an ape. Any
competent zoologist can see from this the little knowledge Virchow
had of systematic zoology and comparative anatomy. However, he
retained his authority as president of the German Anthropological
Society, which remained impervious to Darwinian ideas. Even such
vigorous controversialists as Carl Vogt, and such scientific
partisans of the ape-man of Neanderthal as Schaafhausen, could
make no impression. Virchow's authority was equally great for
twenty years in the Berlin Press, both Liberal and Conservative.
The _Kreutzzeitung_ and the _Evangelische Kirchenzeitung_ were
delighted that "the learned progressist was conservative in the
best sense of the word as regards evolution." The ultramontane
_Germania_ rejoiced that the powerful representative of pure
science had, "with a few strokes of his cudgel, reduced to
impotence" the absurd ape-theory and its chief protagonist, Ernst
Haeckel. The _National-Zeitung_ could not sufficiently thank the
free-thinking, popular leader for having lifted from us for ever
the oppressive mountain of the theory of simian descent. The editor
of the _Volks-Zeitung_, Bernstein, who has done so much for the
spread of knowledge in his excellent popular manuals of science,
obstinately refused to admit articles that ventured to support the
erroneous ape-theory "refuted" by Virchow.
It would take up too much space to attempt to give even a general
survey of the remarkable and enormous literature of the subject
that has accumulated in the last three decades in the shape of
thousands of learned treatises and popular articles. The greater
part of these works have been written under the influence of
conventional religious prejudice, and without the necessary
acquaintance with the subject, that can only be obtained by a
thorough training in biology. The most curious feature of them is
that most of the authors restrict their genealogical interests to
the most manlike apes, and do not deal with their origin, or with
the deeper roots of our common ancestral tree. They do not see the
wood for the trees. Yet it is far easier and safer to penetrate
the great mysteries of our animal origin, if we look at the
subject from the higher standpoint of vertebrate phylogeny and go
deeper into the earlier records of the evolutionary history of the
vertebrates.
Since the great Lamarck established the idea of the vertebrate at
the beginning of the nineteenth century (1801), and his Parisian
colleague, Cuvier, shortly afterwards recognised the vertebrates
as one of his four chief animal groups, the natural unity of this
advanced section of the animal world has not been contested. In
all the vertebrates, from the lowest fishes and amphibians up to
the apes and man, we have the same type of structure, the same
characteristic disposition and relations of the chief organs; and
they differ materially from the corresponding features in all other
animals. The mysterious affinities of the vertebrates induced
Goethe, 140 years ago, long before Cuvier, to make prolonged and
laborious studies in their comparative anatomy at Jena and Weimar.
Just as he had, in his _Metamorphosis of Plants_, established the
unity of organisation by means of the leaf as the common primitive
organ, he, in the metamorphosis of the vertebrates, found this
common element in the vertebral theory of the skull. And when
Cuvier established comparative anatomy as an independent science,
this branch of biology was developed to such an extent by the
classic research of Johannes Müller, Carl Gegenbaur, Richard Owen,
Thomas Huxley, and many other morphologists, that Darwinism found
its most powerful weapons in this arsenal. The striking differences
of external form and internal structure that we find in the fishes,
amphibians, reptiles, birds, and mammals, are due to _adaptation_
to the various uses of their organs and their environments.
On the other hand, the astonishing agreement in their typical
character, that persists in spite of their differences, is due to
_inheritance_ from common ancestors.
The evidence thus afforded by comparative anatomy is so cogent that
anyone who goes impartially and attentively through a collection of
skeletons can convince himself at once of the morphological unity
of the vertebrate stem. The evolutionary evidence of comparative
ontogeny, or embryology, is less easy to grasp and less accessible,
but not less important. It came to light at a much later date, and
its extreme value was only made clear, by means of the biogenetic
law, some forty years ago. It shows that every vertebrate, like
every other animal, develops from a single cell, but that the
course of its embryonic development is peculiar, and characterised
by embryonic forms that are not found in the invertebrates. We
find in them especially the _chordula_, or chorda-larva, a very
simple worm-shaped embryonic form, without limbs, head, or higher
sense-organs; the body consists merely of six very simple primitive
organs. From these are developed steadily the hundreds of different
bones, muscles, and other organs that we afterwards distinguish in
the mature vertebrate. The remarkable and very complex course of
this embryonic development is essentially the same in man and the
ape, and in the amphibians and fishes. We see in it, in accordance
with the biogenetic law, a new and important witness to the common
descent of all vertebrates from a single primitive form, the
_chordæa_.
But, important as these arguments of comparative embryology are,
one needs many years' study in the unfamiliar and difficult
province of embryology before one can realise their evolutionary
force. There are, in fact, not a few embryologists (especially of
the modern school of experimental embryology) who do not succeed
in doing so. It is otherwise with the palpable proofs that we take
from a remote science, paleontology. The remarkable fossil remains
and impressions of extinct animals and plants give us directly the
historical evidence we need to understand the successive appearance
and disappearance of the various species and groups. Geology has
firmly established the chronological order of the sedimentary
rocks, which have been successively formed of mud at the floor of
the ocean, and has deduced their age from the thickness of the
strata, and determined the relative date of their formation. The
vast period during which organic life has been developing on the
earth runs to many million years. The number is variously estimated
at less than a hundred or at several hundred million years.[7]
If we take the smaller number of 200 million years, we find them
distributed amongst the five chief periods of the earth's organic
development in such a way that the earlier or archeozoic period
absorbs nearly one half. As the sedimentary rocks of this period,
chiefly gneisses and crystalline schists, are in a metamorphosed
condition, the fossil remains in them are unrecognisable. In
the next succeeding strata of the paleozoic period we find the
earliest remains of fossilised vertebrates, Silurian primitive
fishes (selachii) and ganoids. These are followed, in the Devonian
system, by the first dipneust fishes (a transitional form from the
fishes to the amphibia). In the next, the Carboniferous system, we
find the first terrestrial or four-footed vertebrates--amphibians
of the order of the stegocephala. A little later, in the Permian
rocks, the earliest amniotes, lowly, lizard-like reptiles
(tocosauria), make their appearance; the warm-blooded birds
and mammals are still wanting. We have the first traces of the
mammals in the Triassic, the earliest sedimentary rocks of the
mesozoic age; these are of the monotreme sub-class (pantotheria
and allotheria). They are succeeded by the first marsupials
(prodidelphia) in the Jurassic, the ancestral forms of the
placentals (mallotheria), in the Cretaceous. See p. 115.
But the richest development of the mammal class takes place in
the next or Tertiary age. In the course of its four periods--the
eocene, oligocene, miocene, and pliocene--the mammal species
increase steadily in number, variety, and complexity, down to
the present time. From the lowest common ancestral group of the
placentals proceed four divergent branches, the legions of the
carnassia, rodents, ungulates, and primates. The primate legion
surpasses all the rest. In this Linné long ago included the
lemurs, apes, and man. The historical order in which the various
stages of vertebrate development make their successive appearance
corresponds entirely to the morphological order of their advance in
organisation, as we have learned it from the study of comparative
anatomy and embryology.
These paleontological facts are among the most important proofs
of the descent of man from a long series of higher and lower
vertebrates. There is no other explanation possible except
evolution for the chronological succession of these classes,
which is in perfect harmony with the morphological and systematic
distribution. The anti-evolutionists have not even attempted to
give any other explanation. The fishes, dipneusts, amphibians,
reptiles, monotremes, marsupials, placentals, lemurs, apes,
anthropoid apes, and ape-men (pithecanthropi), are inseparable
links of a long ancestral chain, of which the last and most perfect
link is man. (_Cf._ the tables pp. 116-118.)
One of the paleontological facts I have quoted, namely, the
late appearance of the mammal class in geology--is particularly
important. This most advanced group of the vertebrates comes on
the stage in the Triassic period, in the second and shorter half
of the organic history of the earth. It is represented only by
low and small forms in the whole of the mesozoic age, during the
domination of the reptiles. Throughout this long period, which is
estimated by some geologists at 8-11, by others at 20 or more,
million years, the dominant reptile class developed its many
remarkable and curious forms; there were swimming marine reptiles
(halisauria), flying reptiles (pterosauria), and colossal land
reptiles (dinosauria). It was much later, in the Tertiary period,
that the mammal class attained the wealth of large and advanced
placental forms that secured its predominance over this more recent
period.
The many and thorough investigations made during the last few
decades into the ancestral history of the mammals have convinced
all zoologists who were engaged in them that they may be traced
to a common root. All the mammals, from the lowest monotremes and
marsupials to the ape and man, have a large number of striking
characteristics in common, and these distinguish them from all
other vertebrates: the hair and glands of the skin, the feeding of
the young with the mother's milk, the peculiar formation of the
lower jaw and the ear-bones connected therewith, and other features
in the structure of the skull; also, the possession of a knee-cap
(_patella_), and the loss of the nucleus in the red blood-cells.
Further, the complete diaphragm, which entirely separates the
pectoral cavity from the abdominal, is only found in the mammals;
in all the other vertebrates there is still an open communication
between the two cavities. The monophyletic (or single) origin
of the whole mammalian class is therefore now regarded by all
competent experts as an established fact.
In the face of this important fact, what is called the
"ape-question" loses a good deal of the importance that was
formerly ascribed to it. All the momentous consequences that follow
from it in regard to our human nature, our past and future, and our
bodily and psychic life, remain undisturbed whether we derive man
directly from one of the primates, an ape or lemur, or from some
other branch, some unknown lower form, of the mammalian stem. It is
important to point this out, because certain dangerous attempts
have been made lately by Jesuitical zoologists and zoological
Jesuits to cause fresh confusion on the matter.
In a richly illustrated and widely read work that Hans Kraemer
published a few years ago, under the title, _The Universe and
Man_, an able and learned anthropologist, Professor Klaatsch of
Heidelberg, deals with "the origin and development of the human
race," and admirably describes the primitive history of man and
his civilisation. However, he denounces the idea of man's descent
from the ape as "irrational, narrow-minded, and false"; he grounds
this severe censure on the fact that none of the living apes can
be the ancestor of humanity. But no competent scientist had ever
said anything so foolish. If we look closer into this fight with
windmills, we find that Klaatsch holds substantially the same
view of the pithecoid theory as I have done since 1866. He says
expressly: "The three anthropoid apes, the gorilla, chimpanzee,
and orang, seem to diverge from a common root, which was near
to that of the gibbon and man." I had long ago given the name
of _archiprimas_ to this single hypothetical root-form of the
primates, which he calls the "primatoid." It lived in the earliest
part of the Tertiary period, and had probably been developed in
the Cretaceous from older mammals. The very forced and unnatural
hypothesis by means of which Klaatsch goes on to make the primates
depart very widely from the other mammals, seems to me to be quite
untenable, like the similar hypothesis that Alsberg, Wilser, and
other anthropologists who deny our pithecoid descent, have lately
advanced.
All these attempts have a common object--to save man's privileged
position in Nature, to widen as much as possible the gulf between
him and the rest of the mammals, and to conceal his real origin. It
is the familiar tendency of the _parvenu_, which we so often notice
in the aristocratic sons of energetic men who have won a high
position by their own exertions. This sort of vanity is acceptable
enough to the ruling powers and the Churches, because it tends
to support their own fossilised pretensions to a "Divine image"
in man and a special "Divine grace" in princes. The zoologist or
anthropologist who studies our genealogy in a strictly scientific
spirit takes no more notice of these tendencies than of the
_Almanach de Gotha_. He seeks to discover the naked truth, as it
is yielded by the great results of modern science, in which there
is no longer any doubt that man is really a descendant of the
ape--that is to say, of a long extinct anthropoid ape. As has been
pointed out over and over again by distinguished supporters of this
opinion, the proofs of it are exceptionally clear and simple--much
clearer and simpler than they are in regard to many other mammals.
Thus, for instance, the origin of the elephants, the armadilloes,
the sirena, or the whales, is a much more difficult problem than
the origin of man.
When Huxley published his powerful essay on "Man's Place in Nature"
in 1863, he gave it a frontispiece showing the skeletons of man and
the four living anthropoid apes, the Asiatic orang and gibbon,
and the African chimpanzee and gorilla. Plate II. in the present
work differs from this in giving two young specimens of the orang
and the chimpanzee, and raising their size to correspond with the
other three skeletons. Candid comparison of these five skeletons
shows that they are not only very like each other generally, but
are _identical_ in the structure, arrangement, and connection of
all the parts. The same 200 bones compose the skeleton in man and
in the four tailless anthropoid apes, our nearest relatives. The
same 300 muscles serve to move the various parts of the skeleton.
The same hair covers the skin; the same mammary glands provide
food for the young. The same four-chambered heart acts as central
pump of the circulation; the same 32 teeth are found in our jaws;
the same reproductive organs maintain the species; the same groups
of neurona or ganglionic cells compose the wondrous structure
of the brain, and accomplish that highest function of the plasm
which we call the soul, and many still believe to be an immortal
entity. Huxley has thoroughly established this profound truth, and
by further comparison with the lower apes and lemurs he came to
formulate his important pithecometra principle: "Whatever organ
we take, the differences between man and the anthropoid apes are
slighter than the corresponding differences between the latter
and the lower apes." If we make a superficial comparison of our
skeletons of the anthropomorpha, we certainly notice a few salient
differences in the size of the various parts; but these are purely
quantitative, and are due to differences in growth, which in turn
are caused by adaptation to different environments. There are, as
is well known, similar differences between human beings; their arms
are sometimes long, sometimes short; the forehead may be high or
low, the hair thick or thin, and so on.