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AND OTHER PAPERS”

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AN INTRODUCTION
TO.A-BIOLOGY¥
AND OTHER PAPERS

A. D. DARBISHIRE

Author of ‘‘ Breeding and the Mendelian Discovery ”

This ‘‘ Worke, although it may not so compleatly answer thy
curious expect, yet let it suffice I have performed my best.”

From the prefatory letter to the reader in ‘‘ An Enucleaire, or
Alphabet of Verbes, Neuters, Common and deponents, profitable
and necessary to all students of humanitie. Likewise for parsing

an helpe extraordinary. Collected and composed by WILLIAM
DarRBIsuHiReE, Philosopher, London, 1624.”

New York ,
FUNK AND WAGNALLS COMPANY
1917

et

CONTENTS

An INTRODUCTION TO A BIOLOGY

APPENDIX TO AN INTRODUCTION TO A BIOLOGY:

1, MENDELIAN PRACTICE IN THE LIGHT OF
BrErcGcson’s BroLocy

2. Norres oF A LECTURE GIVEN IN JULY, 1914,
AT THE GRADUATE SCHOOL OF AGRICUL-

TURE, HELD AT THE UNIVERSITY OF MIs-.

SOURI, COLUMBIA, MIssouRI
3. CORRESPONDENCE WITH M. BERGSON .

4, NoTES AND EXTRACTS

On THE BEARING OF MENDELIAN PRINCIPLES OF
HEREDITY ON CURRENT THEORIES OF THE ORIGIN
OF SPECIES

On THE SUPPOSED ANTAGONISM OF MENDELIAN TO
BIOMETRIC THEORIES OF HEREDITY

Tue Layinec Bare or THE MarnveEL—A LEGEND
t . e

ON THE DIFFERENCE BETWEEN PHYSIOLOGICAL AND
STATISTICAL Laws oF HEREDITY

REcENtT ADVANCES IN ANIMAL BREEDING AND THEIR
BEARING ON OUR KNOWLEDGE OF HEREDITY

PAGE

90

100 -

103
104

127

207

vi Contents

Some TABLES FOR ILLUSTRATING STATISTICAL CoR-
RELATION .

SoME ConDITIONS OF PRoGREss IN BroLocicaL IyQuiry
MENDELISM

FRANCIS GALTON ‘ : : : ; ‘ 4

PAGE

219

239

261

281

PREFACE

ARTHUR DUKINFIELD DARBISHIRE, son of Samuel
Dukinfield Darbishire, M.D. Oxon., was born in
1879, and educated at Magdalen College School and
at Balliol College, Oxford. He worked under Pro-
fessor Weldon for the Honour School of Zoology,
and was placed in the Second Class in 1901. In
October of the same year he was appointed Demon-
strator in Comparative Anatomy at the University.
His interest in the problems of heredity was already
beginning to absorb him. “

At the instigation of Professor Weldon, the leader
of the Biometric school at Oxford, he began a series
of breeding experiments with mice, the results of
which were published in Biometrika. He had a
profound admiration for Professor Weldon, and was,
not unnaturally, influenced at this time by his
hostile attitude towards the Mendelian School. But
when he moved to Manchester, where he filled
the post of Demonstrator in Zoology at the Uni-
versity from 1902 to 1905, he began to think
out on his own lines the problems raised by the
Mendelian discovery. Continuing his experiments
with mice, he set himself to examine the truth of

1“ On the result of crossing Japanese Waltzing Mice with European
Albino Races.” Biometrika. Vol. II., No. 1, Nov. 1902 ; Second Report,

Vol. II., No. 2, Feb. 1903; Third Report, Vol. IJ., Part III., June, 1903;
. Final Summary, Vol. III., No. 1, Jan. 1904.

viii Preface

the position from which he had started upon them.
He had begun as a pupil of the Biometric school
with a strong bias against the Mendelian theory.
He now worked his way, through difficulty and
depression, to a point from which he saw that the
contradiction between the two theories was only
apparent and was really due to a difference in the
point of view from which each party approached
the same facts. He defined his position, and cut
himself adrift from both schools in his contribution
to the debate on heredity at the meeting of the
British Association at Cambridge in 1904,' and in
two papers contributed to the Manchester Literary
and Philosophical Society, ‘On the Supposed An-
tagonism of Mendelian to Biometric Theories of
Heredity ’’ (1905) and “ On the Difference between
Physiological and Statistical Laws of Heredity ”’
(1906).2

He maintained this independent and critical
attitude all his life, and upon no man’s work,
whether of description or interpretation, did he
keep a closer critical watch than upon his own.
‘‘Qne’s attitude as an investigator,” he wrote,
“should be one of continual, unceasing and active
distrust of oneself.” His later experiments with
mice, peas, fowls and rabbits were designed to test
the Mendelian hypothesis with absolutely no pre-
judgment ofthe case. After thirteen years of patient
investigation he could write in February, 1915, “I
consider the Mendelian principles to be still sub
judice ; and they are so attractive by reason of
their simplicity that they need to be under a very

1 Vide infra, p. 162. 2 Vide infra, pp. 144 and 167:

Preface ix

stern judge.” His book, ‘‘ Breeding and the Men-
delian Discovery,” published in 1911, is a clear
summary of his work and thought on the prob-
lems he had himself investigated. From 1905 to
1911 he held the post of Senior Demonstrator
and Lecturer in Zoology at the Royal College of
Science. It was at this period that he came in
contact with Samuel Butler, first through ‘“ Ere-
whon,” then through “Life and Habit,” and his
conception of evolution underwent a profound
change. In his lectures thenceforward he traced
the growth of the theory from the Greek philo-
sophers through Buffon and Lamarck up to Darwin,
and the philosophical bearings of the theory became
for him its paramount interest.

In 1911 he accepted the newly created post of
Lecturer in Genetics at the University of Edinburgh.
The University Experimental Farm at Fairslacks
under the Pentland hills gave him a new field for
his investigations in heredity. His friendly asso-
ciation with Professor Cossar Ewart helped to make
this post the happiest he had held. He had already
become deeply interested by Bergson’s thought
when Bergson himself came to Edinburgh to give
the Gifford lectures in the summer of 1914. He
met and talked with Bergson, had the pleasure of
introducing him to Butler’s theories, and the rare
experience of talking about his own speculations
to a thinker who saw their drift and value.

At the opening of the war in July, 1914, he was
in America, lecturing to the Graduate School of
Agriculture at the University of Missouri, Columbia,

Missouri. As a result of his lectures the University
*

x Preface

immediately offered him a Research Professorship
at Columbia. He was also offered the Professor-
ship of Zoology at the new University of Vancouver.
But he could not reconcile himself to leave England
after the outbreak of war. Owing to physical
delicacy he was at first pronounced unfit for the
Army, and he trained himself for munitions work
at the Heriot Watt Engineering College. But he
found difficulty in getting suitable employment, and
in July, 1915, he tried his luck at a recruiting
office and was enrolled as a private in the 14th
Argyll and Sutherland Highlanders. He devoted
himself to his duties as a soldier with the same
zest and the same meticulous attention to detail
that marked his work in other spheres, and he
won the love and admiration of his comrades. On
Christmas Day, in camp at Gailes, he was taken
suddenly ill with cerebral meningitis, and he died
next morning. Three days after his death he was
gazetted Second Lieutenant in the Royal Garrison
Artillery.

As a man of science he was perhaps unusual in
combining a devotion to pure research (he would
have laughed at the phrase, but all his colleagues
applied it to him) with a freely speculative interest
in his subject. He carried on his investigations with
an untiring patience, watchful in self-criticism, re-
cording his results with the greatest care and thorough-
ness, and persistently postponing interpretation until
he had gathered more results. According to his
principle, he maintained an absolutely dispassion-
ate attitude as scientific investigator. Those who
knew him only in other spheres would not easily

Preface xi

believe that he could be dispassionate about
anything. His interest in the philosophical basis
of his subject was balanced by a close and
intimate knowledge of its practical side. He
hated and suspected all mutual exclusions, sharp
antagonisms, supposed contradictions. Theory and
practice were to him as closely connected as good
with bad or science with art. He believed there
was no such thing as the purely philosophical or
purely scientific or purely practical sphere in his
subject. He had a passion for gardening and for
farming; he liked to be at work in the soil with
the hoe or dung-fork, or amongst the animals on
a farm. His thorough knowledge of horticultural
processes, which contributed so much to the success
of his scientific experiments, was due to his own
experience in all the arts of the practical gardener.
Digging was an art which he carried to perfection
after years of practice.

His delight in doing things as well as they could
be done gave him unusual powers as a teacher.
He took an unconcealed pride in his skill in dis-
section and in elaborate draughtsmanship. In the
laboratory he was always working and learning, and
his idea of teaching was not to give information (he
often refused it), but to show people how to find
out things for themselves. As a lecturer his best
qualification was his absorbing interest in the things
he had to say. His mind was never more clear,
alert, and alive than when he talked to intelligent
listeners. He had the instincts of an actor and a
good deal of the art; and he could get in touch
with his audience at once.

xii Preface

The three greatest influences over his mind and
thought were Beethoven, Samuel Butler, and Berg-
son. They had in common two things that he could
not do without: humour, and the sense that the
source of life is spirit. Their influence was the
quickening influence of one personality on another,
and they were a constant stimulus to him in his
later speculations, which became increasingly meta-
physical in character. He chafed against the ortho-
doxy of science, and his cherished desire was to
make a contribution towards biology in the strict
meaning of the term. The whole field of life should
be its sphere, he thought; its basis should be philo-
sophical and its method dispassionately critical ;
and finally, the spirit in which the biologist ap-
proaches his subject should be the same spirit of
intense interest combined with humility, with which
a lover of music hears a symphony of Beethoven,
or a lover of life meets one of the transcendent
experiences of lite itself.

In character he was essentially childlike; gener-
ous to a fault, with no arrogance, no malice and
no meanness. He had a genius for absurdity, and
he used it, as he used his other gifts, with the
delight of a child and the skill and thoroughness of
an artist. He never made enemies, and he had an
infinite capacity for making friends. The men who
helped him with his experiments, his laboratory
assistants, his gardener, the farmer at Fairslacks
were all to him fellow-workers and friends, to whom
he delighted to express his gratitude, and with whom
he shared, as far as he could, his jests, his interests,
and his ideas.

Preface xiii

All who knew him will keep in memory a person-
ality alive and young to a rare degree, fulfilling
itself in a passion for music, much laughter, a per-
fectly disinterested love of truth, a delight in pro-
ducing delight in others, and the keenest possible
interest in life itself whichever way it led him. |

During the spring and early summer of 1915
my brother was at work upon a book for publica- —
tion by Messrs. Cassell in the autumn. In May he
writes to M. Bergson, ‘“‘I am hard at work on my
book about evolution. I think I am going to call
it ‘ An Introduction to Biology ’—Biology as I think
it ought to be, not Biology as itis. For the problem
of evolution is merely a department of the problem
of life, it appears to me. I am convinced that
the theory of natural selection is in no sense an
explanation of evolution.”

The plan of the book is sketched in a prospectus
written for the Publishers in June, 1915.

*“ An INTRODUCTION TO A BIOLOGY

‘““This book is addressed to all those who are
curious about the meaning of life, and is an attempt
to put before them the essence of the current
mechanistic explanation of the organism and mate-
rialistic explanation of the universe, in order that
they may examine for themselves these accepted
scientific explanations of life. The author does not
pretend to set forth a series of conclusions led up
to by the stages of a logical argument which follow
inevitably and relentlessly from one another, and

X1V Preface

which compel the reader to reach those conclusions
and no other. The reader 1s not offered a set of
irrefragable laws which he must believe, but certain
preliminary considerations which, in the opinion of
the author, effect a clearing of the ground upon
which the foundations of a biology may some day
be laid.

“The term Biology is used by the author to
sionify the interpretation rather than the mere
description of life. The Biology, therefore, in the
interpretative sense, put before the reader is not
a nearly complete fabric the main constructional
lines of which have been laid down once and for
all, and the completion of which will consist in the
filling in of detail; but a tentative indication of
the direction in which some approximation to an
understanding of life may be sought.

‘**The main constructive thesis of the book is
the idea, which we owe to Samuel Butler, that the
details of the process of evolution can be studied
most minutely in man, in whose extra-corporeal
organs, his weapons, implements, and machinery,
evolution is proceeding with great rapidity.

“This study of the evolution of human detach-
able implements leads on to M. Bergson’s thesis
that the human intelligence owes its essential traits
to the fact that it was developed part passu with
the acquisition by man of his control over matter.
Upon this conception of the human intelligence
rests the main critical thesis of the book, which is
the attempt to show that natural selection was
acceptable as an explanation of evolution, because
it was an explanation in terms of matter, and

Preface XV

because it involved the idea that the organism is
no more than a machine.”

The book was to consist of four long chapters,
the contents of which were to be as follows :

I.—The failure of modern interpretative
Biology.

II.—The utilitarian origin of the human
intelligence.

III.—The consequent acceptability to many
minds of a mechanistic theory of the
organism and of a materialistic theory
of evolution.

IV.—Some suggestions as to the direction in
which an understanding of lie may
be sought.

When he joined the Army two chapters
were written, the first revised, the third begun.
The fourth chapter, which was to have been the
constructive part of the book, is entirely unwritten.
In his pocket-book he sketches the plan of the
four chapters characteristically in the form of a
Beethoven symphony :

CHAPTER I.—lst Movement.
CuHapTer I].—Scherzo.
Cuapter III.—Adagio.
CuHapTEeR [V.—Finale.

Amongst his papers the only direct indications
I can trace of the contents of the final chapter are

XViii Preface

Magazine, the Directors of the Highland and
Agricultural Society, The President and Council of
the Royal Horticultural Society.

I am exceedingly grateful to Professor Curtis,
Professor Reed, and Miss M. L. Keene, of the
University of Missouri, for their generous help in
placing at my disposal their notes of my brother’s
lectures delivered at Columbia in 1914.

Professor J. A. Thomson, of Aberdeen, has had
the kindness to read the proots of the first part of
the book, and I have greatly benefited by his know-
ledge and insight in a number of corrections.

I owe a special debt to my friend Mr. A. D.
Lindsay, of Balliol College, Oxford, for his help and
advice throughout the preparation of the book.

HELEN DARBISHIRE.

Boar’s Hitt, OxForD
August, 1916

TO
ROBERT BUCHANAN KING
THIS BOOK IS

DEDICATED

‘

An Introduction to a Biology

bid

CHAPTER I

‘ You who speculate on the nature of things, I praise you not
for knowing the processes which nature ordinarily effects of her-
self, but rejoice if so be that you know the issue of such things
as your mind conceives.”—LEONARDO DA VINCI.

t

§ 1. Man is the best starting-point for the study of life.—§ 2. Scien-
- tific investigation is the human activity, the critical study of
which is the most urgent.—§ 3. Scientific investigation consists
of description and interpretation.—§ 4. Interpretation. Bio-
logical Laws: the urgency of locating them.—§ 5. Words: the
necessity of keeping a sharp eye on the wanderings of their
meanings.—§ 6. A glance at our present interpretation of life
from the historical quarter.—§ 7. On the fitting of theory to

the facts of life.

eg:

HE function of biology, if we adopt the

literal, etymological meaning of the word,

is to describe and interpret the essential
manifestations of life, and to extract from these.
interpretations a conception, or theory, of life. But.
the word “ biology ” has come to be used in certain
very much restricted senses, of which it will suffice
to mention two. In its commonest signification
it merely serves as a convenient common term
for the subject matter of both botany and zoology.

Another common meaning of it is the study of the
B I

An Introduction to a Biology

habits of a particular animal or plant. With re-
gard to this latter meaning of the word, let it be

~ noted that it applies to the behaviour of any animal
except man himself. With regard to the former,
the most common meaning of the word, the reader
may object that biology, dealing as it does with the
comparative anatomy, development, evolution, and
many other aspects of animals and plants, so far
from dealing with a restricted set of phenomena,
ranges over the whole field. There are no other
living things than animals and plants; the study of
animals and plants is the province of biology ; there-
fore biology covers the whole field of life.

The answer to this argument is that the biologist
in his efforts to survey the whole field has forgotten
one animal, himself. In this way he has committed
himself by long habit to the study of those living
things of which his knowledge must perforce be
external, and has shut himself off from the study
of the one living thing which he could know in-
timately. He has preferred to “‘ cover the whole
field’ rather than to dig in the spot where, in my
belief, the return for cultivation would have been
ereatest. The course taken by the biologist may
be illustrated by the difference between a recent

‘sand an early meaning of the verb “to manure.”
In one of its original, literal, and etymological
significations it meant to work the soil with the
hand (that is to say, with the spade, which is an
extended, detachable part of the hand); but the
meaning gradually shifted outwards from the pro-
cess itself to the fertilising effect which the process
had upon the soil; and thence it spread to the

2

Sd

An Introduction to a Biology

other means (besides working with the hand) by
which this effect could be produced, namely, the
spreading of dung over, and its subsequent incor-
poration with, the soil. The biologist has chosen
to ‘‘cover the field” rather than to dig in that
little plot, the study of himself. He has preferred
extension to depth, and in so doing he has followed
the line of least resistance. Anyone can spread
dung; it takes a man five years to learn to dig
well. Man’s attention is so accustomed to look

outwards, that it is very difficult for him to turn

it inwards upon himself. And so the fertile plot
has been very much neglected.

A variety of circumstances has conspired to
exaggerate this extensive character of biological know-
ledge to such a pitch that in his anxiety to leave
none of the field uncovered the biologist has be-
come careless as to whether the covering is thick
enough to be of any use. In choosing subjects for
investigation he has set more store on the novelty
of the result than on the question whether his re-
sults will bring us closer to an understanding of
life. And the result of this aiming at the target
of novelty has often been that he has hit the bull’s-
eye of triviality.

This desire for novelty has become so great that
there is a danger of the convention growing up
that a particular animal or problem is one man’s
preserve, to trespass upon which shall be a breach
of scientific etiquette. And, as it is, the fact that
somebody has worked out the development of a
particular animal is regarded as an argument against
the selection of that animal as a subject of embryo-

3

~

An Introduction to a Biology

logical research; but the truth is, surely, that this
fact should be an argument for such a selection.
For in studying again a development which had
recently been studied, the investigator would be
throwing light upon two problems instead of only
one: upon the meaning of the changes of form
undergone by the animal in its development; and
upon the trustworthiness of the human intelligence
as an investigating mechanism ; and probably more
light upon the second than upon the first. For if
the investigator made a point of looking neither at
the description made by the previous investigator
of the development, nor at his interpretation of the
facts of which this description was a record until
after he had completed his own description and
interpretation, he would obtain results which would
be interesting both to the embryologist and to the
philosopher. The solitary confinement in their own
studies and laboratories, and the complete isola-
tion of biological workers all over the world,
would doubtless be a hindrance to progress in bio-
logical inquiry, at any rate on its applied side;
but it is very doubtful whether the opposite
extreme, the perfect means of inter-communication
now available, is not an equally serious obstacle
to such progress.1 For it ensures the spreading
thin rather than the digging deep.

It is not, of course, true that the biologist has
entirely excluded man from his attention. He has
studied him; but he has done so in the same de-
tached, objective way in which he has studied the

1The probable cessation of communication between the countries now
at war may effect a partial removal of this obstacle.

4

An Introduction to a Biology

other animals. His knowledge of the form of man
is derived from corpses; and he investigates his
performances on the assumption that the human
body is a machine. His attention has been con-
fined to just those attributes of man which can
be studied in the same way as those of non-human
animals. |

This detached, objective method is perhaps the
way to establish a science of human physiology
and anatomy which shall be useful in the practical
science of medicine; but as long as the biologist
persists in studying man in the same impersonal
way as that in which he studies the other animals,
so long will he shut out of his field of inquiry a
whole set of vital phenomena. And the manifesta-
tions of life thus excluded from investigation are
just those which, in my opinion, most deserve the
close attention of the biologist at the present time.

The eye of the biologist has ever been turned
outwards to the pageant of living things by which
he is surrounded. He has forgotten that though
he is a spectator, and probably the only spectator
endowed with intelligent curiosity, he is also a
performer in this pageant.

It is my belief that, so far from excluding from
the sphere of inquiry those manifestations of life
which can only be studied in man, we should give
them a position in the full limelight of our interest.
No biology can lay claim to completeness which
leaves out of account such essential manifestations
of life as human invention, self-expression through
painting, poetry, or music, activities and aspirations
which constitute the very life which each one of

5

An Introduction to a Biology

us leads. Surely the way to find out about life is
to study life at work; or at play; at any rate, in
action. There is no other field at all comparable
with that of human activities for such a study.
It is only in human life that we can approach close
to, and study minutely the very nature of, existence.

| § 2

But there is one human activity which stands
out from the rest and demands the most severely
critical study. This is the process of investigation
itself. It seems to me that one of the most impor-
tant branches of biology should be a critical study
of the process of investigation. It is a perfectly
legitimate branch, because this process is ndubitably
a manifestation of life. It is, moreover, a branch
which requires the most careful attention, because
if the process of investigation be unsound the results
obtained by it will be worthless. Man’s theory of
life, his biology, is the product of his imagination.
Is it not high time, therefore, that he turned his
eye inwards and pondered upon the relation between
himself and the objects of his investigation? It
takes two to make a science. There are two parties
to the bargain: the mind of the investigator and
the things investigated.

The attention of the investigator perpetually flows
outwards, intent upon its object; it does not stop
to look at itself; it is all taken up with its prey ;
none of it is left over to be devoted to its source,
the mind. The interests of the investigator do not

lie within, but without. He has no misgivings as
6

An Introduction to a Biology

to the reality of the outside world or the sound-
ness of his explanations of it, because he has no
misgivings as to the efficacy of his perceptive and
interpretative machinery. Things as he sees them
are things as they are, because his perceptive
machinery is infallible. The causes of things as he
elucidates them are the true causes, because his
interpretative machinery is flawless. That, at any
rate, would appear to be the tacit assumption upon
which he acts.

The reader may object that it is the business of
a philosopher and not of the biologist to deal with
the process of investigation. But if the philo-
sopher to whom the work is given is not an active
investigator, what can he know about investiga-
tion? The eye of the philosopher is turned in-
wards. His mterests are within. He is interested
in the outside world only as the material upon which
his mind feeds, or as a mirror in which it can see
itself.

It seems likely, therefore, that that most inter-
esting region which intervenes between the mind
and things will fall between two stools. The inves-
tigator is interested in the things around him: the
philosopher in the mind within; but very few are
interested in the relation or interaction between the
two. Now the process of investigation is a reci-
procal action which takes place between the two
poles, mind and object, across the region which
intervenes between them. This intervening region
is apt to be neglected because men tend, according
to the inborn direction of their minds, to cluster
around one pole or the other. It must, however,

7

An Introduction to a Biology

be admitted that there is more of the investigator
in the philosopher than of the philosopher in the
investigator. This is only natural. We shall see
later on that it is the essential characteristic of the
mind of man to extend its operation farther and
farther outwards towards things. It is more likely,
therefore, that the interest of the philosopher should
extend outwards across the intervening region to-
wards things, than that the interest of the investi-
gator should extend inwards, across it, to the mind.
For both are men.

To the business of investigation there are, as I
have said, two parties, and it is especially desirable
that the investigator should have his attention
drawn to the one in which he is least interested (if
indeed he ever gave it a moment’s thought),
namely, his own mind.

It must be remembered that in our attempts to
solve the problems of nature we are not in the same
relation to nature as a boy answering an examina-
tion paper is to the examiner. We are answering
questions in an examination paper which we have
ourselves set. The formulation of the problem, in
however honest a mind, must involve some dim
prevision of its solution. The reader may object
that the problem is not formulated in the mind,
but set by nature. I venture to think not. What
appears to me to happen is another result of that
ever outward-streaming nature of our interest, to
which reference has already been made. The prob-
lems originate in our mind, but no sooner have they
taken shape than, all unknown to us because we will
not turn the eye inwards and keep guard on our

8

An Introduction to a Biology

mind, they are swept out, by the current of our
interest, to the sea of things. When they have
arrived there we become conscious of them for the
first time, and so we think that we have found them
there.

So strong is this outward current that even the
human voice is allowed to be carried out by it.
“The facts speak for themselves,” we say. But it
is an illusion; at any rate, a dangerously misleading
figure of speech. Facts do not speak. If the reader
should answer and say, “‘ Well, at any rate they
speak to me,” I would come out and meet him on
the same ground and reply, “ Very well, then; so
do they speak to me, but they do not say the
same thing.” Facts are like the dolls of the ven-
triloquist and say what we want them to. Life in
the hands of the too self-confident biologist is
a very docile doll in the hands of a very skilful
ventriloquist.

The discomfort felt by the investigator when he
is asked by a layman who is taking, or trying to
take, or pretending to take, an interest in his work,
and asks him, “ What are you trying to prove?”
is due to the fact that he sees that this question,
unknown to the asker of it, reveals to him what
he really is doing. He ought not to be trying to
prove anything, but to find something out. But
very often he knows in his heart that he hopes
very much that his pet theory will be proved true
by his investigations. And even if he answers, “I
am verifying certain hypotheses,” he condemns
himself out of his own mouth. For “to verify”
literally means “‘to make true.”

9

An Introduction to a Biology

§ 3

In scientific investigation there are two pro-
cesses. The phenomena are first to be observed
and described; and then, when this is completed,
an attempt is made to interpret them. But it is
very rare that this chronological sequence is strictly
adhered to by the investigator. It is very rare
that, as a necessary preparation of himself, he
deliberately purges his mind of any preconceived
interpretation of the phenomena he is about to
describe. Yet if his description is to be unbiased
and uncoloured by any interpretation, it is obviously
necessary that he should do this. I fear that Inter-
pretation (if I may personify that process for a
moment) at the threshold of a piece of research
does not hold back and say to Description, ‘“ Allow
me—Description first.”” Both rush in together, with-
out ceremony, hand in hand. For they are in-
separable companions. And the result is that in
the work of Description the hand of Interpretation
can always be traced.

‘In its simplest and least dangerous form the
influence of interpretation upon description is seen
in the work of the budding investigator, when he
first embarks upon a piece of “ original research.”
The subject of inquiry is usually suggested by the
lad’s teacher, who, in the worst cases, wishes the
results of the inquiry to point in a particular direc-
tion, and does not conceal his wishes from his pupil,
and who in all cases indicates the lines along which,
and the methods by which, the research should be

carried out. But this is not a dangerous form of
1g0)

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An Introduction to a Biology

the effect of interpretation upon description; be-
cause the young investigator soon comes to have
views of his own, and rebels against his master.
The effect becomes dangerous when it is one’s own
unconsciously entertained interpretations, which, un-
known to us, hold our hand and direct the pencil
which we fondly believe to be carrying out the
pure, unadulterated work of description.

Instances of the way in which the work of descrip-
tion, which is the recording of observation, can be
distorted by preconceived interpretation will crowd
up into the mind of the reader. So great an observer
as Buffon, who was an upholder of the doctrine of
evolutio, according to which the adult animal existed
in miniature, but complete in every detail, in the
egg, said, “I have opened a great many eggs at
different times, both before and after incubation,
and I have convinced myself by actual observation
that the chicken exists, in its entirety, in the middle
of the spot on the yolk, at the moment that the
egg leaves the body of the hen.”

The improvement of scientific instruments since
Buffon’s day has doubtless reduced the margin of
error, but it has not prevented that which has been
seen by means of these improved instruments from
bearing a strange resemblance to that which the
interpretation already in the mind of many a con-
temporary observer made him expect to see.

We have seen the manner in which description
may be affected by interpretation. We may now
glance at the way in which interpretation may be
affected by description.

The reason that the investigator has so little
Il

An Introduction to a Biology

misgiving as to the correctness of his interpretations
is that, however much he ought to have, he has
no misgivings about his observation, nor about
his descriptions of things, and we have seen that
he does not, as a rule, keep observation and inter-
pretation separate in his mind. So that observation
merges imperceptibly into interpretation. No line
is drawn to show where the one ends and the other
begins ; each becomes interpenetrated by the other,
and we come to exist in the pleasant delusion that
interpretation is conducted in the same bright light
as that in which the work of observation is carried
on. A curious instance of this mutual interpene-
tration was afforded by the attitude of the Men-
delian and biometric schools to the Mendelian
phenomena of heredity, and the interpretation of
these phenomena. The Mendelian school were so
saturated with certainty as to the reality of the
Mendelian phenomena, by daily contact with them,
that their certainty spread across the border of
ascertained fact, well into the territory of hypo-
thesis. They could not understand how anyone who
was familiar with the facts could doubt the hypo-
thesis. The minds of the biometric school, on the
other hand, were so full of scepticism as to the
hypothesis that they looked with great suspicion
upon. the facts.

§ 4
The interpretation of a phenomenon consists, in
current scientific phraseology, in discovering the
laws which govern that phenomenon. If it be the

case that the discovery of these laws is the goal of
12

An Introduction to a Biology

scientific investigation, it 1s manifestly desirable that
we should have a very clear idea of the nature of
these laws. It must be admitted at once that
nothing could be better adapted to the obscuring
of their real nature than the phraseology of scien-
tific textbooks.1| We are told that such and such
phenomena are governed by such and such a law
and that this law was discovered by such and such
a person. We should conclude from the word
‘““covern”’? that phenomena are like marionettes
whose performances are regulated by things which
we call “laws”? behind them—at any rate, distinct
from them. The discovery of these laws means,
literally, the uncovering of them and, as a sort of
corollary, the exposing of them to human gaze.
This discovery is not supposed to take the form
of an actual piercing of the ranks of the marion-
ettes to the laws behind, but to consist in a
deduction of the nature of these laws from the
performances of the marionettes. But why this
delicacy ? Why cannot we go behind the scenes
and have a look at these laws, and see what
they are like? Why should there be any mystery
about them? If we are kept in the dark like this
we shall begin to think we have been imposed
upon.

The truth, in my belief, is that we have been

1“ The strong family resemblance which is seen both in the human
species and amongst animals related to each other is a direct consequence
of the existence of the first law of breeding—viz. that ‘like begets like,’
or ‘ tends to produce like.’ Other laws are in operation at the same time ;
consequently when an organism comes within the immediate spheres of
their action the effects of this and various other laws are modified to har-

monise with surrounding conditions.’ [I have been unable to trace this
quotation.—Ep.]

13

An Introduction to a Biology

imposed upon. The reason that we are not allowed
behind the scenes is that there are no laws to be
seen there. But the imposition is the offspring
neither of malice nor of fun, but of thoughtlessness.
It is the result of preoccupation with the results
of investigation, and of inattention to the process
of investigation itself.

A little self-examination would reveal the fact
that these laws exist, not in the world outside, but
in the mind of the investigator. When the biologist
—for I am dealing in this book only with the in-
vestigation of vital phenomena—thinks or speaks
as 1f he thought that he was discovering the laws
determining a set of phenomena, he is, in point of
fact, formulating in his own mind a law to express
certain sequences or regularities that he observes
in these phenomena. It may be objected here that
this is common knowledge, and that such phrases as
‘* discovering the laws which govern a set of pheno-
mena’”’ are merely figures of speech, and that no
one ever really supposed that phenomena were
““ governed ”’ by laws or that these laws were sub-
sequently “discovered’’ by investigators, in the
literal sense of these words. Certainly, such phrases
are figures of speech ; but in my view they are very
bad ones, and ought to be dropped. They are bad
because they encourage the mind to travel in the
direction in which it hkes to travel—outwards.
These laws are formulated in the mind; but as no
watch is kept on the mind they have been caught
up in the stream of man’s interest and swept outwards
to the nether side of things.

If the reader’s patience will allow me, I will try

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An Introduction to a Biology

to give some idea of the picture called up in the
mind, by current scientific phraseology, of the nature
and whereabouts of natural laws, by describing the
theory of music which I held when I was a boy of
about fourteen. At that age music meant to me
simply atune. I thought that a succession of sounds
was either a tune or not a tune. If it was, it was
part of the order of nature; if it was not, it was
simply a noise. Tunes did not differ in merit.
Who was I that I should presume to discriminate
between things which were not the work of man?
I only knew two tunes, “‘ Pop goes the weasel ”’ and
Sullivan’s ‘‘ Prithee, pretty maiden, will you marry
me?” I thought there existed in the world a cer-
tain limited number of tunes; I do not think I
speculated as to their origin, or as to where the
undiscovered tunes were. But I remember thinking
with alarm that if many more men like the discoverers
of “‘Pop goes the weasel” and “ Prithee, pretty
maiden,” arose, all the tunes would soon be dis-
covered. For I wanted very much to discover a
tune myself, but I did not know where to look, or
how to set about the search; moreover, I had no
means of knowing whether, or not, all the tunes
had been discovered; in which case it would be
no good looking. I thought that all known tunes,
together with those which might be unearthed later,
had existed for all time, and had, in the literal
sense of the word, been discovered—that is to say,
located and brought to light by a select few who
knew how to do it. This is the first stage in the
history of my theory of music.

The picture of the laws of Nature which I saw in

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An Introduction to a Biology

my mind’s eye when, as a young man, I read in
scientific books that such and such a person had
discovered the laws governing such and such pheno-
mena was very like my boyhood’s notion of tunes.
I had no reason for supposing that those who wrote
what I read had not thought carefully over the
meanings of the words they used. I took what I
read to be literally true ; I believed that phenomena
were governed by these laws; that they really were
passive agents in the hands of the powerful laws
which controlled them. These laws had existed
from all time, and were part of the order of the
Universe. The law of Natural Selection had been
discovered ; but there might perhaps be one or two
laws of heredity still undiscovered. And just as I
had wanted to discover a tune, so, now, I wanted
very much to discover a law. In my innocence I
believed that if I “ discovered ” the law “‘ governing ”’
a particular phenomenon, I should have got to the
bottom of that phenomenon.

The second stage in the history of my theory oi
music consisted in abandoning the view I have
described, and in rushing to the opposite extreme
of believing that tunes were simply invented by
musicians, ‘‘ out of their own heads,” as one would
have expressed it. This view raised the question
why it was that some men could put together notes
which the world would recognise as music, whilst
others, amongst whom I was compelled to recognise
myself, could not. But I imagined that if anyone
chose to take the trouble to learn harmony and
counterpoint and the rest, and contrived to construct
a symphony which he could entice people to listen

16

An Introduction to a Biology

to now and again, then in the course of time his
hearers would get to know it, or rather to recognise
parts of it when they heard it again; and that in
this way a man’s compositions would gradually
come to be recognised as music.

[According to this view it will be seen that music
was pure invention.

The second stage in the history of my conception
of natural law was analogous to the second stage
in the history of my conception of music. In it I
believed that natural laws were pure inventions of
the human mind, and projected by the mind, or
rather allowed to escape from the mind, into things.

My third and present stage with regard to music
is, to a great extent, a return to the first stage.
Music can convey to us part of the order of nature,
that part which is alive. The great musicians are the
springs through which this message wells up, for us.

My third and present stage with regard to natural
law also returns to the first stage, but it returns a
very much shorter distance. I believe that the present
system of scientific laws relating to life is very much
further from portraying the essence of life, than is,
for instance, the eighth symphony of Beethoven. But
a theory of life cannot be communicated at present
by music, and one must make an attempt to communi-
cate it through the inadequate medium of words. The
point to which we have now reached in this attempt
is that from which we see natural law to be, to.a
very great extent, a product of the human in-
tellect. |?

1 This passage is half deleted in the MS., and was clearly intended
to be re-written. te

Cc } 17

An Introduction to a Biology

The truth of my contention that biological laws
really exist in our own mind, and not in the world
outside, governing phenomena and awaiting dis-
covery, is capable of a simple demonstration. If
the discovery of these laws really were a detection
of the principles underlying phenomena, as the
conventional phrase is, and if the deeper we probed
the more closely did we approach to fundamental
principles, then the deeper we probed the more
closely should we agree with one another. The
very reverse is demonstrably the case. Our agree-
ment is not directly, but inversely proportional to
the depth to which we probe. The truth as it
appears to me is, that we are not really burrowing
under phenomena at all. We invent laws in our
minds about phenomena. Then, looking the other
way—1le. not at our minds—we allow these laws
to escape to the other side of, or underneath, the
crust of phenomena. And then we experience the
thrill of thinking that we have discovered these
laws underlying phenomena. The reason that the
deeper we probe the more do we disagree, is that
the laws that we think we find down there, but
really project there, are the products of our minds ;
nay, almost the portraits of ourselves ; for the truest
portrait of a man is his conception, or theory, of
life. Ifit be asked why there are not as many laws
of, say, heredity as there are men who are interested
in it, the answer is that the great majority of these
men are content to take their laws secondhand from
other men.

In a word, the fact that two men looking, as they

believe, below the surface of one and the same
18

An Introduction to a Biology

phenomenon, can “ discover ”’ there two profoundly
different laws to explain it, seems to me to prove
pretty conclusively that these laws are not de-
tected underneath the phenomenon but projected
below it by the men themselves. What a man
sees below the surface when he looks down the Holy
Well into the waters of Life is not the bottom of
the well, but a picture of himself.

There is another reason why laws should have
flown out from the mind to the nether side of pheno-
mena. The savage’s interpretation of the Universe
endowed everything--river, tree, and storm—with
souls, and ascribed the form and the performance of
these to the nature and activity of their souls. As
this interpretation came gradually to be discarded in
favour of “ scientific’ explanations of things, a void
was left behind the pageant of phenomena; and to
this void it was natural that the new explanations
of things should be drawn.

So that when we feel inclined to congratulate
ourselves on our emancipation from the crudities
of an animistic interpretation of the Universe, we
should ask ourselves whether in fact we have done
any more than hand over the government of the
Universe from a hierarchy of spirits and demons
to one of principles and laws. Very little more,
so far as life is concerned, I venture to think. Many
an innovation in the past has been no more than
the calling of an old thing by a new name.

§ 5
If there is a possibility that words may give a
semblance of progress in interpretation, where in
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An Introduction to a Biology

reality there is none, it is desirable that some at-
tention should be paid to the relation between
words and thought.

Ideally, words are the medium for the com-
munication of thought; thought is the master and
words the servants; thought is wealth, words the
coinage which facilitates its exchange. But actually
itisnotso. By subtle and imperceptible manceuvres
the word has often got the upper hand, so that
thought has come to be at the beck and call of
that which should be its slave.

It is probable that thought and language mutually
interpenetrate each other, so that at the one extreme
there is pure language and at the other extreme
pure thought; in the middle an equal mixture of
the two; and halfway between the middle and
thought, a preponderance of thought over language ;
and half-way between the middle and language, a
preponderance of language over thought. But for
purposes of exposition it will be necessary to make
an arbitrary excision of the intervening region, and
to speak of thought and language as if they were
distinct, mutually exclusive things. The problem
of the relation of language and thought resolves
itself when, reduced to its elements, into the problem
of the relation between the word and its meaning.
Here again, though the word and its meaning are
mutually interpenetrating and interpenetrated, it
will be necessary, for the same reason, to treat of
them as if they were mutually exclusive.

Before I address myself to the problem I would
like to say a word to any philologist who happens
to read these words. I can see the smile on his

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An Introduction to a Biology

lips at any attempt to deal in a parenthesis with
so vast a subject as the relation between language
and thought. But if I may explain, I think I can
turn the smile from one of contempt to one of at
least indulgence. I, too, am appalled by the task
of understanding clearly the relation between thought
and language. It is because I am thus appalled
that I realise that anyone to whose mind the prob-
lem of this relation has not yet even presented itself
is in grave danger of thinking there are no diffi-
culties because he does not see them. A word and
its meaning, especially in the case of ideas (with
which, in this book, we have to deal), are united
together by a slender, elastic bond which is now
contracted, now stretched to its uttermost. The
word, if we consider its whole life since its dim
origin, has been perpetually changing; so too has
its meaning; little in the case of things, much in
the case of ideas. So we see the word and its mean-
ing dancing to each other in an airy medium, like
a pair of gnats in the lee of a gorse-bush. This,
alas! is the simplest case. The more complicated
and much more common cases are those in which
one word has more than one meaning, or where
one meaning has more than one word to express
it; these are the cases which, in verbal life, are
productive of trouble. I have attempted to con-
dense into one simple picture the relation between
words and their meaning. I have tried to convey
my conception by a picture because it is a picture
of a thing which is far less liable to change than
the relation between an idea and the word by means
of which it is handed from mind to mind. It may
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An Introduction to a Biology

be a poor picture. I do not ask the reader to admit
that it helps to make clear the relation between the
word and the thing. I ask him to admit that the
fact that the difficulty of visually disentangling the
movement of a pair, or a harem, of gnats does not
present itself to the mind of an ostrich who has
buried his head in the comfortable sand of matter
hard by, does not prove that this difficulty is non-
existent. De non eaxistentibus. . . .

The phenomenon of which I have given a pic-
ture is the relation of the word and its meaning
regarded from a point of view which envisages the
whole evolution, the whole life of the word and its
meaning from the time of their origin. That was
perhaps too much to attempt. Let us examine the
changes which take place in this relation from a
nearer point of view which only envisages a period
of time so short that the word has undergone no
changes, or only insignificant changes, in that period.
From this point of view the word’ is seen to remain
fixed. When the word denotes a thing like bread,
the thing does not change very much more than
the word which denotes it. That is to say, the
names of things fit closely to them; and the word
“bread ” calls up in the mind the image of bread.
But ideas, attributes and processes are not held
closely by the words which denote them; they are
attached to the word by a bond which varies in
length from case to case, but is usually fairly long.
The word is the fixed point, the peg to which the
leash is attached. The meaning, in such cases, is
the sportive goat who is free to wander anywhere
within the circle, the radius of which is the length

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An Introduction to a Biology

of the leash, and whose chief delight is to browse
off and break through the hedge intended to confine
him to his proper sphere, in the event of the leash
being too weak for its purpose. Do I hear the criti-
cism that I am merely juggling with words? My
answer is that 1 am trying to prevent them juggling
with me—not juggling in an active sense, but in
a passive one, like a chaperon who lets her charges
go where they like, and by not following them,
leads them into trouble.

The wanderings of the meanings of a word may.
be followed in great detail in that fascinating work,
the Oxford English Dictionary. The word “‘ curious”
was used in its Latin form only in a subjective
sense, meaning full of care or pains, careful, assiduous.
Amongst the subjective meanings which it came to
have later were anxious, concerned, solicitous, care-
ful as to the standard of excellence, difficult to
satisfy.

The sense in which I intend the word to be
understood on the title-page of this book is one
which includes all these meanings. The degradation
of the meaning of a good word like “curious ”’ is a
common tragedy of verbal life. Its earliest mean-
ings were qualities of the mind which were worthy
of nothing but praise. It is now and has long been
used in an objective sense merely to denote unusual-
ness in the form or colour of objects.1. And an
attempt has been made to blacken the character

1In the “Philosophical Transactions of the Royal Society for 1703’
(Vol. XXIII, No. 286) there is “‘ A Description of some Corals, and other
curious Submarines lately sent to James Petiver, Apothecary and Fellow of

the Royal Society, from the Philippine Isles, by the Reverend George Joseph
Camel.”’

23

An Introduction to a Biology

of such of the meaning as has remained in the mind,
in order to stigmatise it, as it were, for its lack of
taste In remaining subjective. But in spite of this
attempt, its subjective meaning still retains a cer-
tain dignity and independence of its own. Curiosity
signifies an interest in things which convention has
pronounced to be outside the sphere of the legitimate
interest of mankind, in things which a conspiracy
of silence chooses to ignore. A convention of Modern
Science, for instance, is to regard the prying into
the workings of the human mind as mere meta-
physical curiosity, and the products of such researches
as mere metaphysical curiosities. Sir Ray Lankester,
K.C.B., F.R.S., for example, in his introduction to
“Modern Science and the [Illusions of Professor
Bergson,” says: “‘I am glad to write a few words
by way of preface to Mr. Hugh Elliot’s valuable
little book, entitled ‘Modern Science and the Illu-
sions of Professor Bergson.’ I am glad to do this,
not merely because I think that the books in which
M. Bergson formulates these illusions are worthless
and unprofitable matter, causing waste of time and
confusion of thought to many of those who are
induced to read them, but also because an unmerited
importance has been attached to them by a section
of the English public, misled by the ingenious and
systematic advertisement of M. Bergson by those
who amuse themselves with metaphysical curiosities.”
* Curiosity is a defiance of the conspiracy of
silence, a defiance urgently needed when the topic
which has been pronounced taboo is the operation
of the human mind. The answer to the question
‘Why is this topic taboo’d by Modern Science ? ”
24

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An Introduction to a Biology

is that the eye of science can only look outwards ;
and the scientific mind regards the philosopher
whose eye can look inwards as well, and at all the
points along the line between mind and _ things,
merely as a monstrosity.

In the passage quoted above curiosity is probably
used in an objective sense to mean the products
of subjective curiosity. In the passage which follows
the word “ curious ” is also used in its purely objec-
tive sense: “ To those who in a thoroughgoing way
occupy themselves in collecting and comparing and
classifying all the absurdities which have been put
forward as ‘metaphysics’ or ‘ metaphysical specu-
lation ’ since the days of Aristotle, this latest effusion
has, no doubt, a kind of interest such as a collector
may take in a curious species of beetle. To the
student of the aberrations and monstrosities of the
mind of man, M. Bergson’s works will always be
documents of value.”

The above might be taken as a text for a lecture
on the purely objective nature of our interest in
life. A curious beetle means a bizarre beetle. It
does not mean a fastidious beetle.

The tragedy of the word “ curious ”’ is the result
of the outward-streaming nature of man’s interest.
Most of the meaning has been caught up in the
current and swept out from the mind, and has made
its home amongst things. And even the noun from
which the adjective curious is derived has been
swept outwards too. When the adjective curious
detached itself from its parent substantive, cure
meant care. Thus cure first meant the care of the
healthy ; then the successful treatment of the sick ;

25 Naw

An Introduction to a Biology

and lastly the drug supposed to drive away the
malady. We speak of and even believe in a cough
cure. So different a meaning has “cure” come
to have from that with which it began, that we
could say “better use cure in the old sense than
rely upon cure in the new.”

A word, the meaning of which is very active
at the present time, is the verb to “locate.” It is
used in one sense in Britain, and in another sense
in America, where its evolution has been more rapid ;
but there are signs that the American meaning of
the word is spreading eastwards across the Atlantic.
To locate, in the British sense, is a transitive verb
with a very well-defined, particular meaning; it is
the name for a purely subjective process, which
takes place in the mind—namely, the finding out
of the position of something that Nature or man
is trying to conceal from you.! By saying that
it is a subjective process I mean that, though its
immediate object is external to the mind (such as
a short circuit in an electrical system, or a malig-
nant growth in the body), the next process is within
the mind—namely, the thinking out of some plan
of action to be taken when the trouble has been
successfully located. In America, however, the idea
denoted by the word “ to locate ”’ has, first, become
generalised and enlarged to mean simply “to find.”
I was asked last July in St. Louis if I had located
a satisfactory natatorium in the town. But the
meaning of the word has gone much further than
this; it has broken right away from its original

i“ A useful seaplane reconnaissance located several encampments and

two permanent batteries.”—Scotsman, March, 1915, re Dardanelles: |

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An Introduction to a Biology

moorings which confined it to the mind, and is
used in the passive mood, as synonymous with
“situate,” to denote a purely objective state. The
Century Club is located in West 42nd Street in New
York. In this sense it is an intransitive verb; and
although in this sense it is generally used in the
passive mood, it can also be used in the active
mood, so that one can say that one is going to
“locate? in Milwaukee. What has happened is
this. At one period during its existence on the
American continent this word, which originally applied
to a process which took place in the mind, extended
its application to processes—or rather states—which
are outside the mind. Its meaning, like that of so
many other words, has been caught up in the Kishon
of the mind. The river Kishon swept them away—
that ancient river, the river Kishon.

I have used the word “locate” partly because
it serves to illustrate the habit of the mind to let
its offspring escape from it into the world outside,
but also because the British meaning of the word
denotes a process which has been neglected by the
biologist in his attempt to interpret life. It is
essential that he should locate the laws that relate
to life. I am not asking him to agree with me in
placing them in the mind, but pointing out the
necessity of locating them before talking about
them.

It was said above that the most troublesome
cases are those in which one word has more than
one meaning. The reason that these cases lead to
confusion is that word and meaning are mutually
interpenetrating, so that the flavour given to a

27

An Introduction to a Biology

word from one meaning is transmitted by that
word to another and perfectly distinct meaning.
For instance, the word “law” is used for those
enactments which in human society adjust the
relations between individuals. It is also used, as
we know, for those generalisations made by man
of regularities or sequences observed in phenomena.
But laws, in the latter sense, natural laws as we
call them, have been infected through the word as
a “ carrier,” so to speak, with many of the attributes
of law in the other sense. To such lengths has this
infection proceeded that such absurd expressions as
“the phenomenon obeys the law of gravity,” or
‘* breaks all the laws of nature,”’ are often heard.

Man’s reluctance to keep an eye on the changes
which may be taking place in the meaning of a
word is part and parcel of his reluctance to turn
his eye inwards and examine the operation and
furniture of his mind. The result of this reluctance
is that he never takes stock of the medium whereby
he conveys the results of his thoughts and researches
to others, and whereby he receives such results from
others. Yet if we are going to set out in earnest to
understand life, we must perpetually keep a curious
eye upon the relation between the word and its
meaning.

The reader may take exception to the sentence,
“Tf we are going to set out in real earnest to under-
stand life,” and ask, ‘“‘ Have you the impudence
to suggest that we have not yet even started to
understand life ? Are you utterly ignorant of Modern
Biology ? Or are you wilfully ignoring it? Do you
propose to sweep aside entirely the work of those

28

An Introduction to a Biology

great investigators who have spent their lives in
the service of Biology ?”’ Let us apply the general
conclusions we arrived at with regard to the rela-
tion between words and things to the word “ Biology.”
The area covered by this word includes in one, let
us say its western, region that great mass of (fairly
pure) description of the forms and colours and
behaviour of living things. In its eastern region
it contains a great mass of interpretation little con-
taminated by facts ; and, in the intermediate region,
mixtures of the two in every conceivable proportion.
Now when a man asks himself what he means by
Biology he probably calls to mind the great store
of (fairly well) established facts which make up the
content of descriptive zoology, botany, embryology,
cytology, histology and the rest. But if the man
who indignantly asked the questions above, merely
used the phrase Modern Biology as a bludgeon to
frighten me with, he almost certainly did not ask
himself what he meant by the word biology ; and in
that case he made no attempt to keep the descriptive
and interpretative parts of Biology strictly apart and
distinct in his mind. Until he has done this, it is
impossible to answer the above questions. If he will
do this, I will answer that I certainly do not ignore
the established facts of biology. I am concerned in
this book solely with the interpretation of life; and
I assert that we have not yet begun to understand it.

§ 6
Let us now glance at the relation between the
mind of man and the phenomena of life from the
historical quarter.
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An Introduction to a Biology

Suppose that when biological problems were first
stated, or to speak more accurately, first gradually
took shape in the minds of men, suppose that they
were wrongly stated, suppose that they took the
wrong shape; the solutions of these problems will
not be answers to the questions actually posed by
Nature herself.

I can illustrate my meaning by the following
fable. There was once a man who could only play
one tune, “ Polly winked her eye.” He played it
with one finger only. He learnt it one day, not
from hearing it, but from the notes, spelling it out
with great difficulty. It was in the key of C major.
He got the intervals between the notes correctly,
allowing that there were no sharps and no flats ;
but he began on the note below the one he should
have begun on.

He always played it like this and seemed to
enjoy it. That was how he had ground out the tune
for himself; that was how he always thought of it ;
and that was how it would always exist for him,
But the tune was untrue owing to the initial mistake
he had made.

Are we certain that in our statement of biological
problems we may not have begun on the wrong note ?
The possibility that we may have done so deserves
our earnest consideration. For my part I think we
did begin on the wrong note and that, as a conse-
quence, our present statement of biological problems
does not correspond to the questions posed by Nature
herself ; and as a further consequence, that though
our solutions of those problems may be periectly
correct, they are solutions of problems posed by

30

An Introduction to a Biology

the human mind. I do not maintain that these
problems are entirely fictitious. I do not mean
that they bear no sort of relation to the real problems ;
I think they are a distorted version of the real
problems, that they may be said to bear the same
sort of relation to the real problems as the tune
begun on the wrong note bears to the real tune.
But, of course, some biological problems have been
stated more correctly than others.

The history of biology is a picture of the evolution
of man’s endeavour to interpret life. The picture of
this evolution, as of all other evolutions, is the picture
of a tree: leaves, twigs, branches, trunk, root, root-
lets and root-hairs. This tree is the result of the
solidification of the stream of mankind’s interest in
life. The root-hairs are his first vague curiosity and
bewilderment ; the leaves his most recent publica-
tions and opinions; intervening points on the
branches, trunk and roots, intervening periods in the
history of biology. We will imagine further that
discredited observations and unaccepted interpreta-
tions were represented in this tree by dead wood,
which quickly rotted and fell away.

It seems to me desirable that we should occasion-
ally tear ourselves away from pre-occupation with
the high-water mark of our investigations ; that we
should cease for a moment from our feast upon the
leaves, and descending to the ground, reflect at
leisure, under its genial shade, upon the form of the
tree above us. Reclining there, we should ask our-
selves whether the shape of the tree into which the
course of the stream of inquiry has solidified, is the
right shape, whether some of the wood in it ought

31

An Introduction to a Biology

not to have been cut out, and whether some that
died and has long since disappeared ought not to
have survived and altered the shape of the tree. In
other words we should ask ourselves, are we working
in the right direction ?

For my own part, I believe that at certain points
in the history of our attempts to interpret life wrong
signals were given and that as a consequence we are
at present working along the wrong lines. I am not
concerned at present with the nature of this false
step ; all ] am concerned with now is to express my
belief that the satisfaction of the biologist with our
current scientific interpretation of life is the satisiac-
tion of the fool with the paradise which he has built.

§ 7
The cocksureness of the scientific biologist should
surely be the cause of the gravest misgivings. The
more certain a man is that he is right the more
probable is it that he is wrong; because it means
that facts are as soft clay in his hands, and his cer-
tainty moulds them to his purpose. It is the diffident
investigator who tentatively offers us a hypothesis
which, in his modest view, brings some of the facts
into line, who should inspire us with confidence. It
is the theory which seems to fit the facts in places
but seems remote from them in others (as, for in-
stance, the theory of sex based on clinical, Mendelian
and cytological phenomena and upon the facts of
parasitic castration) and not the theory which
peremptorily brings all the facts into line, which
should seem to us to be likely to be true.
If a man came to me to-morrow, full of con-
32

An Introduction to a Biology

fidence and certainty, and well pleased with himself,
and said, ““I have now got a theory which fits all
the facts,’ I could think one of two alternative
things about him.

I could think that this man, by a miracle of
energy, had become acquainted with all the mani-
festations of sex, and that his theory did fit, down
to the very smallest undulation, the surface of the
phenomenon, as a glove fits a woman’s hand. That
is to say, I should think that he had made up the
deficit in the facts by the discovery of the remainder,
and that he was now able to give a theory which fitted
exactly, simply because he had now got all the facts
at his disposal.

Or, I could think that he had not made any
difference in the stock of facts at his disposal, but had
invented a new theory, which fitted the same number
of (but probably fewer) facts, only in the sense that
a child’s hand can be fitted into a steel gauntlet.
That is to say, I should think he had made a new
theory which really bore very little relation to the
facts ; touched them at one or two points but fitted
them at none. The theory might be a pertectly
consistent one. He would not invent a theory which
was not a consistent and organic whole. Indeed it
is generally admitted that it is more important that
a theory should be consistent with itself than that
it should fit the facts closely. For it is considered
that the worst thing that can be said against a man
who is patiently trying to fit one part of his theory
to one set of facts and another part of it to another
set, is that the two parts of his theory are not con-
sistent with one another.

D 33

An Introduction to a Biology

If I believed the first alternative I should think
that his certainty was due to the periect fit between
theory and phenomenon; if I believed the second
I should think that certainty was due to absence
of fit between theory and phenomenon. Certainty
can be bred in the mind by these two extremes ;
not by an intermediate stage. Are there any theories
concerning vital phenomena about which certainty
can be due to perfect fit? Can there be any vital
phenomenon that we know so intimately in every
undulation of its form, every nuance of its colour,
or every phase of its movements that there can be
a theory which fits all this exactly ? Possibly in
the case of some exceedingly simple phenomena (if
such exist), certainty is due to perfect fit. But does
it seem likely that, for instance, the certainty in the
mind of so many that Natural Selection is the ex-
planation of evolution, that tremendous phenomenon
of the growth of life, the features of which we can
but dimly discern, does it seem likely that this
certainty can be due to perfect fit ?

An old artist and a young artist both arrived in
Venice not long ago, on the same day. At the end
of a month the old artist had painted nothing; it
was too beautiful; he knew he was not equal to
painting a picture which could express to him the
manifold magic of the place; he knew that nothing
that he could produce would fit reality. The young
artist, however, made many sketches, with each of
which he was well pleased. He had no difficulty
in expressing what he saw, because he saw so much
less than the old man did. Nor would he know that
he saw less because Venice to him would be the

34

An Introduction to a Biology

Venice that reached him through his eyes; Venice
to him was less than it was to the old man. Is not
the growth of life more manifold even than Venice ?
Yet the man of science thinks that he has explained
evolution.

Look at the matter from the point of view of the
maker of the theory. Suppose he has a theory which
fits a set of facts at some points. Man is in a hurry
to explain what he sees. Will he not, rather than
spend years in gathering new facts, impatiently, but
unconsciously, round off the theory to cover the
facts already before him ?

Then there is a question whether a theory which
fitted the facts closely would be acceptable to the
mind. Is it not possible that all that the mind can
understand, is mind? I mean, it seems likely that a
mind is incapable of recognising (a necessary prelim-
inary to understanding) anything but the workings
of another mind not very widely different from itself.
' That is to say, it can only recognise the usual, fairly
rigidly fixed features, the deeply ingrained habits of
thought—the eyes, nose, mouth and ears, so to speak,
which are common to all minds.

When it is remembered that two minds can be so
different as to be as unintelligible to one another as
is that of the poet to that of the stockbroker, or that
of Beethoven to that of Weber, who, when he heard
the Seventh Symphony thought that Beethoven was
mad; when we see how one mind can be so utterly
unintelligible to another, is it conceivable that such
a thing as a theory which has no mind (human mind,
I mean) in it at all would be even recognisable, much
less intelligible, to the mind? Suppose that the

35

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An Introduction to a Biology

mind is suddenly confronted with an apparition, a
theory, which fits a phenomenon so closely, down to
the smallest crevice, that the theory showed none
of the features of the human mind at all but only a
cast of those of the phenomenon, the apparition
would mean nothing to the mind at all (unless the
phenomenon to be explained was a product of the
human mind). ‘But if the mind were confronted with
an apparition which was sufficiently like a mind to
show that it was the offspring of a mind, but also
showed, by the indentations on it, what phenomenon
that mind had been pressing its face against, then
the mind would be confronted with an apparition, a
theory (as, for instance, Natural Selection, a theory
involving such essentially human ideas as utility and
competition) which it could at once understand.
In other words, a perfectly fitting theory would be
utterly unintelligible to the mind. A condition of
the intelligibility of a theory, it seems to me, is that
it must not contain too much of the phenomenon
(unless that phenomenon happens to be a product
of the human mind) or it will be unintelligible. It
must, of course, be, or have been, in contact with
the phenomenon at one or two points, just to show
which phenomenon it is supposed to be explaining.
We have, therefore, an argument for the view that the
acceptability of a theory is evidence not of the accu-
racy with which that theory fits the phenomenon, but
of its remoteness from it. In other words, an accept-
able theory is more likely to be one which resembles
the mind, than one which resembles the phenomenon
(provided that that phenomenon is not also a product
of a mind, such as a murder or a machine).
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An Introduction to a Biology

This argument will probably be uninteresting or
meaningless to those who are not accustomed to
fitting theory to fact ; and nonsensical to those who
are so accustomed. Men who are commonly engaged
in the task of making theories to explain things
may be classified into three categories according as
the things to be explained relate to (1) man; (2)
living things other than man; (3) not-living things.
The first category is occupied chiefly by the criminal
lawyer, the second by the biologist, the third by
the engineer, the physicist, the chemist, and so
forth. |

That the lawyer would think it nonsense would be
proof of its truth. The lawyer’s business is to fit
a thing which is entirely human mind, 1.e. his theory,
to another thing which is also human mind, namely
the actions of a particular man or woman. If his
theory fitted exactly it would be the exact cast of
which the mould was the action of the prisoner ;
and so would be immediately acceptable to and
intelligible to the mind. (Ii the reader is inclined to
find fault with my metaphor and point out that the
cast is not similar to, but the opposite of the mould,
I would refer to the well known optical illusion which
consists in our inability to say whether a given
arrangement of graded light and shadow is a mould
or a cast, unless we already know, or have strong
reasons for guessing, beforehand, which of the two
it is.)

I cannot help thinking that the method of the
court of law, with its weighing of evidence and so
forth, whilst admirably adapted for the work of
finding out what a particular woman or man has or

37

An Introduction to a Biology

has not done, is not suited to the investigation of
extra-human vital processes. In the first place the
problems in the two cases are totally different.
The function of the court of law is simply to find out
what a man has done; and, so far from its being
the case that the court is concerned with discovering
the cause of the prisoner’s action, the fact is that a
pretty confident and usually justified visualisation of
his motives, i.e. the cause of his probable action, by
the jury, is used only as a means of finding out what
he did. But the task of the biologist is not to find
out whether a particular animal or plant did or did
not, on a certain occasion, do a certain thing. The
non-possession by non-human animals and plants of
a speech intelligible to man makes it impossible for
them to lhe to us. And, of course, in point of fact,
we do know a vast amount about the actions of plants
and animals, especially man. For we cannot he to
ourselves about our own actions, though we may
about our motives. The task of the biologist is to
interpret, to find a meaning in those actions of living
things that he knows about; or, to put it so that it
embraces the whole domain of life, to explain such
manifestations of life as fall within his ken. The
application of the method of the court of law to this
task seems to me to be one of the most flagrant
examples of the use of tools designed for specific
practical requirements in the wild-goose chase after
truth. pees

Let us now pass straight on to the third category,
that of the physicist and chemist, and leave the
biologist out, for reasons which will appear shortly.

It 1s held by M. Bergson, and I agree with his conclu-
38

An Introduction to a Biology

sion, that the intellect of man has been developed as
a by-product, nay indeed is little more than a product
of the process of utilisation and control of matter by
man.! And whether we incline to the view that this
development has been the invention of a conception
of matter to fit the rigid features of the mind, or to
the view that it has been the modelling of our at
first plastic manner of thinking to suit the hard
crust of matter ; in a word, whether liquid matter has
been poured into and cast in the mould of mind, or
liquid mind has been poured into and cast in the
mould of matter; to whichever of these views we
incline, we believe that the mind thinks in terms of
matter, and that a theory of any manifestation of
matter which fits that manifestation closely will be
acceptable to and intelligible by man, simply because
matter has been moulded on mind, or mind on
matter. And therefore to the engineer, the chemist
and physicist and other occupants of the third
category, my thesis that a theory which fits the
facts at all closely will be unintelligible to the mind,
will be nonsensical. My thesis will be rightly con-
sidered untrue by these men because they are dealing
with matter, by means of an instrument, the intellect,
designed for the purely practical purpose of dealing
with matter ; and by the lawyer because he is dealing
with certain phases of human activity by amechanism,
the court of law, designed for that very purpose.
The lawyer is fitting human mind to human mind.
The physicist and chemist are fitting human mind
to matter, upon which the human mind has been
moulded. So, of course, to both these classes the

1 Bergson, “ Evolution Créatrice.”

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An Introduction to a Biology

closer the fit of the theory to fact, the greater the
intelligibility of the theory.

But what about the biologist ? He will think my
thesis nonsense too. For not only does he, because
he is a man, think most comfortably in terms of
matter ; but also because he endeavours to interpret
life in terms of physics, chemistry and mechanics,
he borrows his ideas about the fitting of theory to
fact from the physicist and the rest. Glance for a
moment at the series covered by our three categories :
(1) lawyer; (2) biologist; and (3) physicist. In its
broadest sense that series covers (1) man; (2) life;
and (3) matter. The biologist has started with
matter because he is most at home there; and he has
tried to interpret life, and even man, in terms of
matter. In a sense, too, he has started from the
other end, i.e. from man, in his attempt to interpret
life. But he has laid hold of the least vital thing
about man that he could have chosen; for he has
done no more than borrow the purely utilitarian, un-
sympathetic and impersonal method of the court of
law to investigate life. And thus life has been en-
filaded by a withering fire from both ends; our
theory of life has no life left in it; and we think
of life as machinery, and of the organism as a
machine filled with a variety of chemicals, meekly
obedient to the laws of chemistry, physics and
mechanics.

But to return; the biologist had to make a theory
which fitted. Was he going to wait till-he had taken
into account all the manifestations of life, especially
those exhibited by man? Nothe. Indeed he could
not if he would. Preoccupation with the extensive

40

An Introduction to a Biology

properties of matter almost invariably carries with
it an atrophy of sympathy with the varied manifesta-
tions of the spirit. The biologist who believes that
a living thing is a machine, naturally feels em-
barrassed in the presence of things which he utterly
fails to understand; so he rules them out of court
as ‘sentiment ” or “‘ superstition.” Life itself, with
its component individualities, no two of which are
alike ; with its extravagance and its parsimony, its
beauty and its ugliness, its utter misery and its
bouncing fun; all this is a disconcerting spectacle to
the biologist who comes to it laden with the ready-
made moulds, the concepts which he has borrowed
from the chemist, the physicist and the mechanist.
In the presence of Life does he throw away his moulds
and try to understand it? Not he. He gathers up
his moulds, hurries from the uncongenial atmosphere,
and retires to that comfortable sanctum, the recesses
of his own mind, where he can think how he likes,
and use his moulds; and having bolted the door
against all but the purveyors of such moulds, he
constructs a theory of life aiter his own heart, a
machine. ‘“‘ Nature,’ he says, “1s a vast and
orderly mechanism, the working of which we can,
to a large extent, perceive, foresee and manipulate,
so as to bring about certain results and avoid others.”
And he enjoys “‘ that happiness and prosperity which
arises from the occurrence of the expected, the non-
occurrence of the unexpected and the determination
within ever-expanding limits of what shall occur.” }

1Sir Ray Lankester’s Introduction to ‘‘ Modern Science and the Illu-
sions of Professor Bergson,’’ by Hugh S. R. Elliott, p. x. Longman and
Co., 1912.

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An Introduction to a Biology

And when his labours are over he sings :

‘* Life is a vale, its paths are dark and rough
Only because we do not know enough.
When Science has discovered something more,
We shall be happier than we were before.” }

He thinks that he has become far removed from
the jagged crust of phenomena in the vale that was
dark and rough. And so he has. He thinks that he
has burrowed through the soil, which was easy ;
through the subsoil, which was not so easy; through
the intervening strata, which was still more difficult,
until at last he has reached fundamental principles
and stands upon the Bedrock of certainty itself,
But he does not. It is all an illusion. It is true
that he has become removed from the crust of pheno-
mena. But it is in the other direction. He has
flown upwards on the wings of his imagination, in
the machine which he has made, and will soon
become a tiny speck, infinitesimal against the
evening sky.

I have endeavoured to give some idea of the
dangers which beset the path of him who is not
satisfied with a mere description of Life, but sets out
to understand her and to convey his interpretation
to others. If these dangers are so great as to be
insuperable, would it not be safer and simpler, we
ask in despair, to rest content with a mele descrip-
tion, with a photograph instead of a picture of Life ?
Ii we did this, we should certainly make fewer mis-
takes; but we should not make much progress.

1 Tambkin’s Remains,” p. 20. Published by the proprietors of the
J.C. R., at J. Vincent’s, 96, High Street, Oxford, 1900.

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An Introduction to a Biology

We could not go far wrong, but we could not go far.
No. Let us not play the poltroon’s part. Let us
locate the dangers and know them so that we may
guard against them. Besides, Life challenges us to
interpret her. Our best chance of understanding
life is to study life in movement, that is to say, in
evolution. In our next chapter we shall glance at
the evolution of man with a view to finding out what
habits of mind he has contracted. Having done
this we shall be in a better position to answer the
question whether the theory of life, especially the
explanation of evolution by natural selection, which
constitutes the orthodox biology of the present day,
is acceptable to man solely because that theory has
been east in the mould of his habits of thinking ;
and whether this theory is not, in fact, so remote
from life as it really is as scarcely to bear any rela-
tion to it at all.

CHAPTER II

“The lower animals keep all their limbs at home in their own
bodies, but many of man’s are loose, and lie about detached.”
—SAMUEL BUTLER.

“< We shall sce that the human intellect feels at home among in-
animate objects, more especially among solids, where our action finds
its fulcrum, and our industry its tools.”—HENRI BERGSON.

§1. Tool and limb the same.—§ 2. Closer analysis of § 1.—§ 3. Still

a closer analysis of § 1.—§ 4. Evolution extra-corporeal in man.—
| § 5. Tool and intelligence knit up together.—§6. Evolution of
warfare, industry and the chase.—§ 7. Warfare.—§ 8. Industry.—
§ 9. Extension of body followed by extension of mind.

§ 1
HE essential difference between man and the
other animals is often stated to consist in the
fact that man uses tools whilst the non-
human animal does not. But I think that the
difference between the two can be stated more
accurately. The difference consists rather in the
fact that the tools used by the wild animal are
formed by the modification of its limbs, whilst the
tools used by man are made by him out of wood,
stone, or metal, or such other solid or tough things
as he can find or make. This statement minimises
the difference between the limb and the tool. I
have called them both tools. Butler, in the sentence
which stands at the head of this chapter, calls them
both lmbs.! It does not matter what names we

1“ Brewhon,” A. C. Fifield, 1908, p. 270. °
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An Introduction to a Biology

tether them to, so long as we realise that there is
no essential difference between, for instance, the
claws of the shore-crab and the forceps of the ana-
tomist ; and that such difference as there is lies in the
fact that the latter can be detached when no longer
required and attached when wanted again, while
the former is a useful tool only so long as it remains
part of the body of the crab.

Mere detachability, however, is not the essential
feature of the human implement, because it happens
that in the case we have chosen from the other
animals the implement can be detached. If the
claw of a crab is badly injured it can be voluntarily
cast off by the crab, by a deliberate transverse
fracture of the limb near the point where it is at-
tached to the body, but not, curiously enough, at
a functional joint. A new limb is then grown in
the place of the discarded one. It is an interesting
but not a surprising fact that a crab has to be in
very good health to be able to perform the operation
of amputating its own arm in this way. This
amputation may also be performed by a crab when
its limb is securely held by an adversary.

The essential difference between man and the
other animals cannot, therefore, be expressed in the
simple statement that man is distinguished from
other animals by the fact that he is a tool-using
animal. Limb and tool are two names for the same
thing. Nor does the difference lie in the fact that
this thing, whether we call it limb or tool, is detach-
able in man and not detachable in other animals.
For we have just seen that it is detachable in the
crab. The difference lies in the fact that man can

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An Introduction to a Biology

lay aside his implement when he has done with it and
pick it up when he wants to use it again. And
this involves at the moment when he lays it down
a looking forward to the time when he will want
it again; and, at the moment when he wants it
again, a looking back to—that is, a memory of—the
time when he laid it down. Here we get our first
glimpse of the essential feature which distinguishes
the mind of man from that of other animals—namely,
the fact that the human mind extends its operation
much further forwards and much further backwards
than does that of the other animals.

§ 2

This essential identity between the tool (or limb)
which is part of the body and the tool which is de-
tachable from it is a very important point to grasp,
because it forms the starting point of our study
of evolution in man.

I am aware that this thesis conflicts with what
may be called a sensible scientific view of the matter.
According to that view the claw of the crab corre-
sponds with the hand of the man; the tips of a
crab’s claws correspond with the tips of a man’s
fingers, and not to the points of his forceps whilst
he is holding them. But this scientific view surely
does not express the whole truth. To know the
real living thing we must see it in relation to its
surroundings and know how it obtains’ its food,
and how it escapes from or defeats its enemies.
A specimen of a crab in a bottle shows you the
crab accoutred with the full panoply of armour and

weapons which protect him from his enemies and
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An Introduction to a Biology

from the elements ; and provided with the full set
of implements by means of which he obtains what
he requires from nature. In fact, the crab is seen
with everything by means of which he comes into
relation with inanimate and animate nature. But
a naked man shut off from his implements is de-
prived of all this; he lacks clothing which shelters
him from the elements, and if he has no spear and
no spade he must shortly starve. So that, looked
at from a point of view from which one sees the
bond between the organism and its environment,
the implements of man do correspond with the
limbs of an animal. I am aware that my argument
may appear obscure; but the incidence of the
words at my disposal is responsible for much of
the obscurity. There is no difficulty in the human
sphere; there are plenty of words for that with
which man carries out his work—tool, weapon,
implement, instrument, apparatus, machine—each
with its own well known incidence of meaning.
But in the sphere of extra-human animals the choice
of words is much more difficult. For instance, limb
does not cover the snout of the hog, which corre-
sponds with a man’s potato-fork. Perhaps the best
word is organ, which means that with which work
is done—i.e. that which effects the bond between
the organism and its environment.

_ The matter may be looked at from the closer,
"purely sensual aspect. The implement, whilst one
is using it, certainly feels as if it were part of one-
self. It)is true that when one first uses it it does
feel like a foreign object in one’s hand. But by
the time that one can use it well, one comes to feel

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An Introduction to a Biology

as if it were part of oneself. The skilled dissector
and surgeon soon comes to feel as if the forceps
were elongations of his fingers; and in general his
dissecting instruments, whilst he is using them,
become in a very real sense living parts of his hands.
The word “surgeon” is derived from the Greek
cheirourgos, which literally means one who does
(delicate) work with his hands. For the sense by
which one traces a nerve or a vessel is a blend of
the senses of sight and touch. This sensation of
touch must be transmitted to the brain through the
instrument as well as through the hand and arm.
Therefore, though there 7s a difference between hand
and instrument in the faculty of transmitting sensa-
tion, the difference is not so great that a hard and
fast line can be drawn, in respect of this faculty,
between instrument and hand. The hand is merely
the haft of the tool, that part of the body into
which the instrument (as its name implies) is built.

§ 3
** Life, he urged, lies not tn bodily organs, but in the power to

use them, and in the use that is made of them—that is to say, in the

work they do.” —SAMUEL BuTLER, ‘“ Erewhon Revisited,” p. 128.

‘The difference between the limb and the imple-
ment, between the claw of the crab and the forceps
of the anatomist, is a perfectly simple one,” it may
be objected. “ The claw is alive and the forceps
are inanimate.” The answer to this objection is 5
that the business part of the claw is just as dead
as the forceps are; or, if the reverse phrasing
preferred, is no more alive than the forceps, in use,

are. Both are made of inanimate matter; both
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An Introduction to a Biology

become active at the bidding of the organism to
which they are in the one case temporarily, and in
the other permanently attached. The crab makes
his claws of lime which he elaborates inside him-
self, whilst man makes a pair of forceps of iron
which he elaborates outside himself. But there 1s
no difference in the matter of aliveness between
the lime and the iron; both are of lifeless matter
moulded to suit the purpose of the organism which
uses them. The living thing has to arm himself
with hard matter at the chosen points of himself
where he comes in conflict with the world of matter.
The particles of matter of which a rhinoceros horn
and a man’s dagger are built are prisoners made to
fight against their comrades—matter impressed into
the service of life in its battle with matter. The
difference between implement and limb cannot,
therefore, I think, be stated to consist in the dead-
ness of the former and the aliveness of the latter.
Our reluctance to admit that the implement of
a man is in any sense a part of him is due to our
ingrained habit of thinking in terms of matter,
which makes us regard the real essential living
being as co-extensive with its body. That is why
we think the claw to be part of a crab but refuse
to admit that the forceps are a (detachable) part
of the anatomist. But the essence of an organism,
as its name implies, lies in the work which it does ;
ot in the chemical elements out of which it is made.
_And as regards work done, the claw of the crab
nd the forceps of the anatomist are perfectly
analogous to one another.
The general conclusion which I believe to be -
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An Introduction to a Biology

indicated by the foregoing argument is that, though
on a materialistic view it is a perfectly simple matter,
and the organism ends where the body ends, and
there is an end of it, there is probably a mutual
interpenetration between the organism and matter ;
and the difference between man and the other
animals is that the latter are obliged to welcome
all matter they want to make use of instrumentally
within the four walls of their bodies ; whilst man is
enabled by the invention of the system of detach-
able organs to keep the great bulk of the matter
which he impresses into his service at arm’s length.

§ 4

Evolution, therefore, in man consists no longer
in a modification of the shape of the parts of his
body. At any rate, if this corporeal change is
going on, it is taking place very slowly and is not
very interesting. Evolution is proceeding with great
rapidity in those organs of man which “are loose
and lie about detached”’; this is the whole argu-
ment of the Book of the Machines in Samuel Butler’s
** Hrewhon.” Bergson expresses exactly the same idea.
‘‘Chaque machine nouvelle étant pour ?homme un
nouvel organe,—organe artificiel qui vient prolonger
ses organes naturels,—son corps s’en trouva subite-
ment et prodigieusement agrandi . . . etc.’?

With the origin of man, evolution along the line
of man left the plane of corporeal change and rose’
to that of extra-corporeal change. Before the origin

1 Institut de France. Académie des Sciences Morales et Politiques.
Séance Publique Annuelle, du samedi 12 Décembre, 1914. Discours de
M. Henri Bergson, Président.

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An Introduction to a Biology

of man life had to express itself through the arduous
medium of modifying its own form; but with the
origin of man life had, like an aeroplane just rising
from the ground, gathered sufficient momentum to
lift itself from the arduous plane of self-modification
to the more elastic medium of a supple intelligence
which could give form to matter without incor-
porating that matter with its own body. It is as
if the superabundant energy of life, which could
only spend a mere fraction of itself through that
cumbrous medium, the modification of its own form,
burst forth, when once that brake was taken off
by the invention of detachable organs, into a wild
career of evolution driven onward by the immense
reserves of energy pent up within it.

§ 5
It is a commonplace that it was the assumption
of the erect posture by man which released his fore
limbs from the drudgery and routine of locomotion,
and set free his hands for more delicate and versatile
use. But it should be remembered that it was be-
cause man had preserved the simple pentadactylous
hand of his amphibious ancestors, and had resisted
every temptation to specialise his hand in the various
directions in which it has been differentiated through-
out the vertebrate series; it was because the line
_ of life which led to man bided its time in this way
that when the intelligence of man had reached the
stage at which it could devise and fashion imple-
ments, his hands were of a form and of a sensitiveness

suitable for the purpose.

Or suppose we do not incline to the view that

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An Introduction to a Biology

the ancestors of man bided their time, but believe
that it was lack of energy in the line which led to
man, which left man with such an unspecialised
—that is, with such a backward—hand, then we
see in the fact that he was able to profit by this
mistake the familiar mark of the good craftsman
exhibited at an early age. All fashioning, whether of
implements or of sentences, consists fundamentally
in the intention to carry out a design. But the
finished article is only in part the result of the
carrying out of the design as intended; it is also
the result, and often to a very large extent, of our
ability to profit by mistakes on the way.

So, whether we incline to the view that man
had the ability to profit by the lack of energy on
the part of his ancestral line which left the hand
undifferentiated, or to the view that the preserva-
tion of an undifferentiated type of hand was the
result of energy and foresight, the fact remains that
it was the possession of this simple type of hand
which rendered possible the manufacture and use
of tools. But this bald statement does not, I fear,
give a very true picture of what happened.

The mind has an inveterate habit of thinking
in terms of cause and effect. It hkes to see things
in pairs, end on; and to think of the second as being
the effect of the first, which is the cause. This form
of thought is probably moulded on everyday human
action. The cause is the counterpart of our action ;
the effect that of the response produced. Our mind
is at ease when it can think in terms of a pusher
and a pushed ; of cause and effect. And it is natural
that we should apply this way of thinking in our

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An Introduction to a Biology

pursuit of the truth. So we would lke to think
that man started the use of tools because he had
attained to a certain degree of intelligence; or we
would like to think that the use of tools resulted
in the sharpening of the intelligence. It is more
probable that a slight advance in the one led to a
slight advance in the other, which thus got ahead
and was able to pull the first after it. But one
must beware of forming an image of this process on
the analogy of so practical a matter as the progress
of two things which are the puller and the pulled
by turns, like two children bicycling down a gentle
gradient hand in hand.

We must dig deeper in the mind for an analogy,
and I suggest that we find it in the relation between
seeing and drawing. There is little doubt that the
reason why a man cannot draw is not, as the mechan-
ist thinks, that his arm and hand are badly con-
structed for the purpose of drawing. The fault
jies not in the arm but in the mind. Man, accord-
ing to his usual custom, shifts the cause as far
outwards as possible; and the bad workman even
puts it in his tools. When a man cannot draw, it is
because he cannot see truly. On the other hand it
is certain that drawing is a great aid to seeing;
in fact, it may almost be said that a man has not
truly, fully, and vividly seen a thing until he has
drawn it. If, then, a man’s drawing cannot improve
unless his vision becomes truer, and if the improve-
ment in his vision depends on his drawing better,
each is waiting for the other to make a move, and,
logically, stagnation should be the result. But,
logic or no logic, the fact remains that drawing and

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An Introduction to a Biology

seeing, if persevered with, do help each other in
a mutual way. Nevertheless, seeing takes the lead.
No amount of drawing can make a man a visionary ;
but no amount of dissuasion and difficulties will
prevent a visionary from drawing. It is therefore
within that we must look for the source of progress.
It is probable that the relation between the use
of tools and the development of the intelligence
was of this mysterious kind. It was a fertile inter-
action, and so rapidly productive, on both sides,
that it may be likened to the case of snails, whose
mode of locomotion is so arduous, and opportunities
of meeting so few, that they have developed an
arrangement (hermaphroditism) whereby when they
do meet each member of the pair becomes both the
father and the mother of a numerous progeny.
Increased skill in the fashioning and use of imple-
ments would sharpen the wits of the artificer; and
this gain in intelligence would be devoted again to
its source, the making and use of tools. And so
the two, intimately associated, would advance from
conquest to conquest. The first rude implements
of flint would give man an advantage over the beasts
which unarmed he did not possess. He would thus
not only vastly increase his supply of food and of
raiment, but also—as did, for instance, the reindeer
men of France—discover new sources of material,
bone and horn, for his tools. Much later, when
he discovered that he could further increase his food
supply by sowing the seeds of the sorts that he
ate, he would find that the seeds would grow better
if he worked the soil with the tools or weapons
that he had. He might find that the spear-head
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An Introduction to a Biology

was not the best shape for a tilling implement, so
he would alter the spear-head and adapt it to a
new purpose, or make a rude mattock and see how
it worked. A different type of implement would
be required for a hatchet, a different one for grind-
ing corn, and so on. How interesting these early
experimentings must have been! How man’s whole
mind must have been taken up with this new joy
of making something! What new sources of interest
were discovered to him when he first made a flint
knife ! .
Not only was this new occupation for his min
operating through his hand absorbingly interesting,
it was immensely advantageous too. It not only
satisfied his mind, it also brought clothing for his
back and food for his larder, and kept the wolf
from the door. And, all the time, the fashioning of
implements and the growth of his intelligence were
playing into each other’s hand in a variety of ways.
One thing the invention of the detachable limb
did was to set free an immense amount of energy.
It is probable (but I do not press this point now)
that the making of an implement by the modifi-
cation of one’s own body requires much more highly
concentrated, that is to say, much more energy
than conducting, outside of oneself, the manufacture
of a detachable implement. (If this point seems
nonsensical to the reader it is because he is assum-
ing what we are about to discuss, the truth of a
mechanistic theory of the organism, and a mechan-
istic theory of evolution—namely, natural selection.)
But whether this is so or not, it is certain that a
great amount of energy was saved by getting rid
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An Introduction to a Biology

of the necessity of carrying the implement about
with one for the whole of one’s life. The energy
thus set free by the invention of the detachable limb
would be put back into capital to be devoted to
the further improvement of the liberating invention.

The animal can never put down its tools. Man
by gradually devising the detachable tool would
gradually come to divide up his time, into that
time in which he had his tools in his hand and that
time in which he had laid them aside. These leisure
moments might be devoted to the imagining of
new ways in which he could use his rude flint tools,
and new ways in which he could make his tools
out of the chunk of flint; as, for instance, the
utilisation for skin-scrapers or arrowheads of the
flakes which he struck off the core of the flint whilst
making his spear or mattock. But it is more prob-
able that such ingenuities would strike him whilst
he was actually absorbed in the business of manu-
facture, and that in his leisure moments he would
think to himself how pleasant and how profitable
was his work. He might even occasionally and
dimly contemplate the wonders of the universe.

But in those hard days these reveries must have
been rare, and such flights as his imagination took
were not the voiced exaltation of the lark, but the
silent intent manceuvring of the hawk. Thought,
at first, was all transitive, all intent on the task of
escaping beasts of prey and providing for oneself
and family. Par

The existence of man in those early days must
have been terribly hard. The very thing which was

destined to make him lord of creation might very
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An Introduction to a Biology

nearly have led to his undoing altogether. The in-
vention of the detachable limb was made possible
by the preservation of the archaic pentadactylous
hand of his remote amphibian ancestor. But it
seems as if man knew, or the line of life which
led to man knew, that man was destined to
acquire detachable weapons and implements and
armour. For not only the hand but the whole of
the body too was left unspecialised, and utterly
unprovided with offensive or defensive weapons and
useful implements. Man had neither the armour
of the crocodile, the portable house of the tortoise,
the warm clothing of the bear, the swift hoof of
the horse, the horn of the ox, the fangs of the lion,
nor poison of the serpent. The non-specialisation of
any of his organs as weapons or implements left him
utterly defenceless when he was removed from his
detachable limbs. Unable to defend himself, he
ran to nature for protection and passed much of
his life in the dark recesses of caves. Naked and
unfurnished in his own person, he had to com-
pensate for his lack of natural clothes, weapons,
and tools by a super-bestial ingenuity in the in-
vention of artificial ones.

The exercise of this ingenuity would give him
a pull over his enemies by sharpening his intelligence
in a way already hinted at. The laying down of the
tool when done with involves a looking forward to
the time when he will want it again; and the picking
of it up, a memory of the use for which it is intended
if not of the time when it was laid down. This ex-
tension of his attention, forwards and backwards,
came to be the chief distinguishing feature of man,

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An Introduction to a Biology

as compared with the other animals. He would
compete with the beasts of prey not by superior
strength but to a certain extent by superior cun-
ning ; to a greater extent by his armoury of detach-
able weapons and implements, and perhaps still
more by this new faculty of looking forward—of
pro-vision, in fact. The forward extension of his
intellectual vision would probably be accompanied
by backward extension of it. It may even be that
this forward extension of the intellectual vision
necessarily involves a corresponding backward ex-
tension of it, as a man cannot walk away from a
mirror without his image walking away from it in
the opposite direction. At any rate, without such
an extension of the intellectual vision backwards the
forward extension of it would not be of much use.
With it man would begin to provide for the future
on the basis of the remembered experience of the
past. The domestication of animals, started by
accident, continued out of curiosity, and systematised
for profit, would stimulate and be stimulated by
this faculty of looking forward. So, at a later stage,
would the tilling of the soil. It was this long range,
therefore, of the intellectual vision of man as com-
pared with that of the other animals, which, although
at first the result of need, contributed, along with
its source, the use of tools, more than anything else
did to make its possessor the lord of creation. The
way in which the meaning of the word “ pro-vision”’
has been caught up, like that of the word “cure,”
in the outward current, and swept from its original
subjective moorings in the mind, so that it means

no longer an intention, nor the acting upon that
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An Introduction to a Biology

intention, but the actual things which we buy
from a provision merchant, may serve to illus-
trate the purely utilitarian character, at the time
of ,its origin, of that extension of the range of
interest which is one essential feature of human
evolution.

It was not, however, only in a forward and back-
ward direction that the mind of man extended its
range as an indirect result of this invention of detach-
able implements. The invention would also vastly
increase the versatility of man. Man by this in-
vention would come to bear the same relation to the
other animals as the great actor who can play any
part does to the poor one who can only play one.
For the invention of the detachable limb carried with
it the possibility of possessing a greatly increased
number of limbs and this implied so many new
points of contact between man and the outside
world. The animal whose limb has become the
implement for the performance of a particular function
is so highly specialised that he is destined to be in
contact with the world of matter only at one point.
Indeed, the name for the new power with which the
detachable limb endowed man—namely versatility—
means the ability to turn round and meet the outside
world at all, or, at any rate, at many points. It
is probable that the only parts of the outside world
that interest a crab are those which will sooner or
later come to be handled with its claws. The
question seems to me to be not whether a crab can
be said to possess forceps, but whether a crab is
really very much more than a walking pair of

forceps.
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An Introduction to a Biology

§ 6

If we attempt to visualise the beginnings of in-
dustry, warfare, and the chase, we shall, I think, see
that they flow from two or three sources, the pro-
ducts of which unite to form a common stream,
or, at any rate, to flow in a common broad channel,
which, however, in its turn soon begins to divide
up again in the delta of differentiation. Warfare
and sport must both have owed their popularity to
a great extent to the pleasure of shedding blood.
Necessity must have contributed very largely to
all three, whilst the insatiable curiosity of man must
have played an important part in the origin and
development of each, but especially in that of in-
dustry. For if Necessity was the mother of Inven-
tion, Curiosity was almost certainly its father. But
I would prefer to attempt to express the truth with
regard to the origin of human activities not in terms
of cause and effect, but by suggesting that the rela-
tion between necessity and curiosity on the one hand,
and adventure and invention on the other was of
that obscure, reciprocally fertilising kind already
indicated.

The chief objection to this that I can foresee is
one which arises from the difficulty of understand-
ing how necessity could be in any way the result of
adventure or invention. But the essence of adven-
ture surely is that you risk all in the attempt to
gain something, and in the risking of all you may
lose an arm which leaves you in the direst necessity
or need. Also invention involves the abstraction

of the mind from the practical business of provision,
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An Introduction to a Biology

and its concentration upon the work in hand; the
approximation to the mind of the focus of its
interest would soon lead to utter want, unless there
were someone to provide for the inventor.

Another objection which may possibly be brought
is that love of adventure is not an essentially human
characteristic. This objection I should be prepared
to admit in part. For it would seem that the adven-
ture which attends the life of the lion is not merely
the result of necessity, but is also the result of a
love of adventure for its own sake. I cannot think
that a lion is as happy eating a horse’s head he
has been given, in a cage, as eating a zebra’s head
he has taken, in the wilderness. Still, the love of
adventure for its own sake has undoubtedly been
accentuated in man; the climber amongst the peaks
of the Himalayas is not there in search of food.
But is it not possible that our reluctance to grant
a love of adventure, in any considerable degree, to
animals other than man may be due to our ignor-
ance of their lives; and to that orthodox theory
of evolution (natural selection) which obliges us to
think that an animal is what it is and does what
it does because if it had been ever so slightly less
efficient it would have been eliminated in the struggle
for existence? For in the cases of the few animals
of whose lives we have been given a detailed picture
—as, for instance, of the Adélie Penguin, in a de-
lightful book, “‘ Antarctic Penguins,”’ by Mr. Levick
—there seems to be no escape from the conclusion
that a great many of their actions are inspired by
roguish fun, as when the penguins pushed each

other into the water, or by the sporting instinct,
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An Introduction to a Biology

as when they climb an ice-cliff for the excitement
of it and then come down again.

Again, if the reader were to object that invention
is not an essentially human attribute, I should be
inclined to agree with him. If he argued that a
bird’s nest was as ingenious an invention as an
Indian’s wigwam, or an eggshell made out of lime
as a pot made out of clay, I would not disagree.
For my belief is not so much that the intelligence
of man differs from that of the other animals in
kind, but rather that it differs from it in range.
Both stream outwards; that of the animal a little
way to a few things, that of man a long way to
many things.

But whatever may have been the relation be-
tween, on the one hand, the origins of industry,
wartare, and the chase, these three, and, on the
other, the springs of human action, it is probable
that the early course of each of the three, receiving,
as it did, contributions from all of the springs,
would be very largely determined by, and would
in its turn to a great extent determine those of the
other two; as, indeed, would be inevitable in the
case of three currents flowing in the same channel.

This degree of community in the origins of in-
dustry, wariare, and the chase must in the early
days have found its expression in the manufacture,
where possible, of a tool which would be equally
useful in the provision of food, in tribal aggression
and defence, and in the peaceful arts. The rudest
flint implement was probably as much weapon as
tool. When the working of flint was in its infancy

and the manufacture of tools was slow, the man,
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An Introduction to a Biology

for instance, who was flaying a kid with an instru-
ment not also adapted for defence would be at a
great disadvantage if he were suddenly attacked.
But there had soon to be a parting of the ways;
and the difference between essential features of the
evolutions along the two diverging routes of weapon
and tool may be glanced at. ©

§ 7

In fighting or hunting, a prime necessity is to
hit your enemy or your quarry before he can hit
you, and the dominion of man over the other animals
means nothing more than that he can outrange
them. This outranging is effected by the artificial
elongation of the arm in two ways: either by the
actual elongation of the spear or lance which is
too good to throw away, or by throwing a detach-
able weapon, which may be anything from a stone
to an explosive shell.

He who stands upon the parapet of the great
earthen fortress upon the crest of the White Horse
Hill, in Berkshire, near Uffington, which was Uffa’s
farm, but nearer to Woolstone, which was Wulfric’s,
and withdraws his gaze, in space, from the great
Vale spread before him, past the green hollow
at the foot of the hill, where from five sources the
erystal Ock tumbles and splashes out of the hidden
face of the chalk (and doubtless supplied the garrison
with water), and, casting his mind’s eye back-
wards in time a thousand and few hundred years,
to the days when not iar from there the hosts of King
Alfred defeated the Danes, pictures to himself how
attackers of the fortress would have to scramble

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An Introduction to a Biology

up its steep sides and how the defenders would hurl
them back down into the moat below, and there
pound them with stones and transfix them with
javelins. He who calls up such a picture to his mind
sees for himself how early the cunning of man har-
nessed to his weapons the auxiliary force of gravity.
The bow, the catapult, and the arbalest were sub-
sequent utilisations of other auxiliary forces. But
the great step in the increase of range was, of course,
brought about by the invention of gunpowder.

That we intuitively think of weapons as part of
our arms is shown by the fact that we call them
arms,! and that we refer to the flying corps, for
instance, as a “‘ fourth arm.” The whole object of
war is to deprive your enemy of the artificial elonga-
tion of his arms, to disarm him by killing, wounding,
or catching him. All man’s offensive and defensive
organs are detachable. That is the difference between
him and a lion. The only way to disarm the lions
in the Zoological Gardens in Antwerp, in case they
were released by a shell, was to shoot them.

§ 8

It is natural that in the case of weapons the first
thing to be done was to increase the range, and the
simplest way of effecting this was the utilisation of
external forces. But in the case of implements it
was not the maximum distance irom, but a con-
venient proximity to the object which was the
desideratum. So that the fashioning of implements
had proceeded to great lengths before any other
motive force was employed than the energy of man

1 See Skeat, etymology of arm.
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An Introduction to a Biology

himself. And the first utilisation by man of ex-
traneous forces in industry, if we may enlarge the
scope of that term to include agriculture, was liter-
ally a harnessing; when the burden of supplying
the labour required for tilling the soil was shifted
from the fore-arm of man on to the shoulder of
the ox. One of the greatest inventions ever made
by man was the wheel. Without it the impressing
of steam, electricity, and petrol into the service of
man would not have been possible. The wheel
bears the same relation to the extra-corporeal evolu-
tion of man as the feather does to the corporeal
evolution of birds. Machinery would be impossible
for man without the wheel; flight impossible to
birds without the feather. And it is a fact that
the feather, an annually detached device, which
combined, in a manner hitherto undreamt of, the
minimum of weight with the maximum of resist-
ance to the air, was invented (or, if the mechanist
object, “was grown’) by an animal who was
much more reptile than bird, and who was dis-
covered fossilised at Solenhofen, and _ called
“Ancient wing” or Archeopteryx by another
animal (calling himself “‘man’’?), who was des-
tined, in a very few years, to learn to fly himself.
The wheel, by taking off the brake imposed by
friction and gravity, enabled man to take the burden
from his own shoulders and put it in a cart which
he or a beast of burden could draw. There seems
to be little doubt that the first use to which the
horse was put was to harness him to a cart. It
was not till a much later date that man learnt to

ride the horse. The chronological relation between
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the invention of the wheel and the domestication
of the horse can never be more than subject for
guesswork, but it is probable that as a human
instrument the cart came before the horse. The
need for a strong animal to pull a big cart may
have been the chief incentive to the domestication
of the horse, but it is known that the cart came
before the saddle. Man, by the invention of the
wheel, as everywhere else in his battle with matter,
has secured an advantage only at the price of com-
mensurate danger. For although in most cases
this brake imposed by Nature was a hindrance, there
are times when it Is a necessity ; as when the driver
of a tram-car puts, or tries to put, the brake on
again when his car is running down a gradient. And
in general, although it cannot be doubted that the
material welfare of man has been immensely in-
creased by the invention of the wheel, without which
the machinery necessary to modern industry would
be impossible, it 7s extremely doubtful whether his
spiritual welfare has been increased to a like extent ;
and it is certain that the wheel has been responsible
for many horrible deaths and for many miserable
lives. True, without the wheel we should be with.
out the automobile and the cinema; but without
it we should also have escaped many of the horrors
of civilisation. However, it 1s too late now. We
have grown the wheel and we cannot—at any rate,
we will not—cut it off. The earliest form of wheel
was probably a tree-trunk along which an object
too heavy to lift, like the gigantic monoliths of
Stonehenge, was rolled. From this clumsy stage

a great stride was made forward by the invention
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of a device, the axle, whereby the wheel went along
with the cart; in the activities of peace this in-
vention greatly facilitated the work of transporta-
tion; and in warfare it put great power into the
hands of the men who used it, by enabling them
to do the next best thing to being in more than one
place at the same time—namely, to get from one
place to another in a very much less time than
their adversary. ‘“‘ And the Lord was with Judah ;
and he drave out the inhabitants of the mountain ;
but could not drive out the inhabitants of the
valley, because they had chariots of iron ”’ (Judges
4,19).

It was not, however, only by taking off the brake
imposed by gravity and friction that the wheel let
loose the avalanche of man’s material prosperity.
The potter’s wheel gave him utensils which, amongst
other things, enabled him to carry and store water,
and thus lengthened the apron-strings which bound
him to springs and rivers. The spinning-wheel
contributed to warmth and comfort.

The wheel could not have been invented before
evolution had got on to the extra-corporeal stage
jn man, because the wheel must, whilst fitting closely
round its axle, be absolutely separate from it. Such
an organ in a vertebrate would have to consist of
a bony disc, with either a hole through its centre,
or with an axle which was part of it and which fitted
into a horizontal hole in the skeleton, such as the
acetabulum. Such an organ could not be used until
it was fully grown and had come to consist only of
dead bone, because it could not be used until it had

become a separate piece from the axle, after which
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moment no further blood-supply to it would be
possible. Up till the moment when the wheel was
full-grown, wheel and axle would be of one piece.
Once the last drop of blood required for the full
development of the wheel had passed into it, the
blood-vessels and other tissues in the wheel would
begin to atrophy, and a cylindrical separation would
take place between axle and wheel, or between axle
and socket, and the wheel would be free; and not
till then would the wheel be an esse a wheel; for
then, and not till then, would the wheel possess the
essence of the wheel, whichis rotability. Up till that
critical moment in the life-history of the cyclo-
phorous vertebrate it would be a helpless tetra-
cycle with the brake jammed on. An attempt to
move the animal long before the liberation of the
wheel would spoil the wheel for future use by wearing
it flat in one place; a similar attempt nearer the
time of the liberation of the wheel would produce
death or grave disorder by hemorrhage of the axle.
And then, when the wheel had become rotable in
the fullness of time, the animal could not move
of his own accord unless only his hind limbs had
been modified into wheels and his front ones were
legs; if he were a tetracycle on the level he would
remain stationary unless he had domestic animals
to pull him about; if he were on the side of a hill
he would probably be wrecked. This attempt to
visualise the origin of the wheel before evolution
had got on to the extra-corporeal stage seems to
me to show that the wheel would not have been of
any use before the mind had gone far enough to

conceive of a cart, and to make the tools good enough
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to make a cart with. It was not until man had
deputed the labour of haulage to his beast of burden
that the wheel became an important factor in human
economy. For the chariot preceded the wheel-
barrow. It was not, therefore, till the man had
detached from himself both the matter of which he
makes his organs and the power which sets them in
motion that the wheel could begin to show itself
above the horizon of practicability.

But the early naturalists evidently did not think
that the growth of a wheel presented any difficulties
to even the lowliest organisms. Certain animalcules
possess a circlet consisting of a great many vibratile
cilia (delicate whips of protoplasm) ; and the waves
passing rapidly round this circlet, like waves on a
field of corn, but produced not, as in the cornfield,
by an external agency, the wind, but by the volun-
tary supination in extremely rapid succession of
the cilia composing the circlet, make an excellent
imitation of a revolving wheel. This is the descrip-
tion of one of these animalcules by Leeuwenhoek !
in 1702: ‘‘ Out of the same sheath appear’d a little
Creature, the fore-part of whose Body was roundish,
and presently from the same Rotundity proceeded 2
little Wheels that had a swift Gyration. The Limner
observing the Rotation of the Wheels, which always
ran one and the same way, could not be satisfied
with the sight, adding, O, that he could always
see such a wonderful kind of a motion.” It is a
tribute to the early naturalists who took this imita-
tion for the reality and dubbed these animalcules

1“* Philosophical Transactions of the Royal Society,’ Vol. XXIII.
No. 283.
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‘“ Wheelbearers,” or Rotifera; for it shows that
they thought of the essence of a wheel, not analytic-
ally, in terms of matter, as a thing made of hub,
spokes and rim; but intuitively, in terms of per-
formance, simply as ‘“‘ that which revolves.”

The wheel put power into man’s hands in a variety
of ways. It cannot be said that the pulley enabled
him to lift weights heavier than he had lifted before,
for the horizontal monoliths of Stonehenge were
probably lifted without its aid. But the pulley cer-
tainly facilitated and expedited to a very great
extent the labour of lifting. The windmill and the
water-wheel are results of the utilisation of tre-
mendous natural forces which could not have been
impressed into the service of man (on land) but
for the previous invention of the wheel. But the
stream and the wind cannot be said to have been
subjugated by man to the extent that steam, elec-
tricity, petrol and gas have. The stream and the
wind serve man at their pleasure and not at his;
it is natural, therefore, that it is in association with
the more completely domesticated and controllable
forces like steam, electricity and the rest that wheels
should have attained to the highest stage of their
differentiation. How essential a part in those extra-
corporeal organs of man which we call machinery
the wheel plays is illustrated by the fact that in
the picture called up in the mind by the word
** machinery ” wheels are the dominant feature. How
essential a part the wheel played in the origin of
machinery may be gathered from the fact, which is,
I think, obvious, that without it it is difficult to see
how steam, electricity and gas could have been har-

=,

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An Introduction to a Biology

nessed as motive powers. I{ man can be said, as
I think he undoubtedly can, to be the only animal
that has made a fortune, it was the wheel more
than anything else which enabled him to do so.
That man regards the wheel not as a mere dead device
but as an externalisation of himself, and endowed
with a vitality which becomes its own, is shown
by the way in which the wheel appears to the in-
tuition of the savage and of the poet. It is recorded
how some Kaffirs, when they first saw a Huropean
wagon, ran along by the little front wheels cheering
them for being able to go the same pace as the
big back wheels.’ And the mother of Sisera did
not complain of her son’s horses, but cried: “ Why
is his chariot so long in coming? Why tarry the
wheels of his chariots ? ”’

§ 9

“What is a man
If his chief good and market of his time
Be but to sleep and feed? A beast, no more.
Sure He that made us with such large discourse,
Looking before, and after, gave us not
That capability and godlike reason
To fust in us unused,”’—HAMLET.

In this chapter I have suggested a view of human
evolution which will, I believe, help us to under-
stand evolution in general—that is to say, the growth
of that vast organism (or worker) which we call life ;
and may possibly bring us nearer to an understand-
ing of the meaning of that growth. I am aware
that it may be said that the view which I have taken
of human evolution is a merely fanciful one. But

1“ The Essential Kaffir,”” by Dudley Kidd,
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An Introduction to a Biology

the fact that it can be labelled with the word “‘ fanci-
ful’ does not prove that it is not taken from a
point from which we get a very good view of human
evolution. I do not, of course, pretend that it is
a true view. Human evolution and, still more,
life itself, will probably always remain a mystery
to us. All that we can hope to do is to approach
a little closer to an understanding of these immense,
unfathomable things.

To say, as I have said, that man really makes
with extended parts of his hands everything which
he makes by machinery may seem to be the taking
of a deliberately fanciful view of modern manu-
facture. But the very word we use for this vast
business shows that man instinctively regards all
this making as, in origin, if not in essence, a making
with the hand. Through the hand the body of
man has extended outwards, and has become pro-
digiously enlarged.’ Through the hand, the mind
also has flowed outwards and has become pro-
digiously enlarged. Or, to state what has hap-
pened in other words, the gradual increase of man’s
control over matter has been accompanied by a
gradual extension of the field of operation of his
intelligence. Thus man differs from other animals
not in the direction of the flow of his attention, for
both flow outwards, but in the distance to which
that attention reaches. The attention of the hen
flows outwards to the handful of objects which
constitute her universe; but there it stops. Man,
by inventing detachable organs, has made so many
new points of contact between himself and the out-

1P, 50, supra.
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side world, and so many new channels through which
his mind can flow out into, and run about amongst,
external objects. The word “discourse,” which
occurs in the quotation at the head of this section,
expresses exactly what the human mind has done:
it has run about in all directions. But in this dis-
coursing man’s mind has run along the same tracks
as those taken by the progress of his control over
matter. The mind at first followed in the paths
cut out by the hand; then, looking ever farther
ahead, gradually insinuated itself into the position
of leader. So that now it is not necessary to make
a device with the hand, to see if it will work; the
mind is so familiar with the properties of matter
that it can foretell whether it will work or not before
it has been made. The human mind owes this long
range, so to speak, which distinguishes it from that
of the other animals, to the apprenticeship which it
served in the factory, in the most literal and ele-
mental sense of the word. It was because it learnt
to think in terms of matter that it acquired the
habit of looking forward, of foretelling. If the
earliest object of the mind’s interest had been life,
it would never have developed the long range which
it acquired from its familiarity with imert matter.
Can a man and a woman foretell what their children
will be like? No. It was because the education
of the mind began with a study, for purely utill-
tarian ends, of the properties of substances like
wood, flint and leather, and the behaviour of
things lke the lever, the spring and the wheel; it
was because the mind received its early training
in a course of applied mechanics that it was able
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An Introduction to a Biology

to acquire the habit of predicting the perform-
ance of things, of extending the limits of its
vision and of pushing its horizon farther and
farther away.

Life during man’s defenceless infancy was so
hazardous and earnest a thing that, although the
mind by its power of foretelling had insinuated itself
into the position of leader previously occupied by
the hand, the whole activity of the mind, the only
weapon man had, had to be concentrated upon
securing the victory in the desperate struggle for
his very existence. But in the period of rest which
followed the decisive victory which the mind,
operating through the hand, won over the elements
and the wild beasts, the mind, accustomed to cease-
less activity, could not lapse into idleness. It would
need a rest, but it would take it, not by doing nothing
but by doing something else. Much of it would be
needed to retain the ascendancy which he had
established, to consolidate the position which he
had won. Much of it would be devoted to the
peaceful arts of industry and agriculture. But some
of it would be free to wander where it listed. Ex-
hausted by actual wandering in space, it would take
its rest by imagined wandering in time. Only in
the case of men like Alfred the Great are all these
three activities to be found within the compass of
a single mind. As a rule, a man is destined by the
original direction of his soul to be either warrior,
husbandman or poet. That, however, is a minor
point.

Once the mind has won the leisure which enabled
it to wander, there were no limits to its discoursings.

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Released from the close application of the very
struggle for life, in which a mistake meant certain
disaster, the mind, with its vastly increased range,
would be directed towards the beginnings and the
ends of things. But as a mind, hitherto focused
upon the close hard work of existence, could know
nothing about either, it would have no difficulty
in inventing a consistent theory of the origin and
fate of all things—a perfect circle dinted at no
point by contact with reality. Puffed up by his
victory over the elements and the brutes, man had
no conception of his intellectual limitations. For-
getting that he acquired the long range of his in-
tellectual vision by the handling of inanimate objects,
he had the temerity to apply it to the interpretation
and even the origin of hfe. He forgot that his
mind, now on holiday, although emancipated from
service to the hand, still had deeply ingrained in
it the habits acquired during its long servitude.
Thus he thought of life, and the Universe too, as
having been created by a God, just as his own
tools, weapons and utensils were created by him-
self. That he really thought that God was both
in form and habit merely a very powerful man,
and had created the universe in exactly the
same way aS a man fashions a pot, is shown
by the fact that he explained his own origin by
saying that this God created him after His own
(God’s) image.

This view of the origin of life in all its forms,
including man, was satisfying to man for many
years, because it was in harmony with his habits
of mind and was not contradicted by what he knew

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about life. It also continued to be satisfying for
another reason. Man invented this idea of the
origin of life as we now see it with the same instru-
ment, the mind, as that with which he would devise
a tent. He therefore not only imagined that living
things had been made just as he would make a
tent, but he also applied the same criterion of truth
to his explanation, as of trustworthiness to his tent.
If there was a flaw in the construction of his tent,
it. would fall about his head in a storm. If there
were error in the making of his theory, it would
recoil upon him. But it did not recoil upon him ;
so apparently it was worthy of trust, it was true.
Or perhaps he thought, what a great many people
think to-day, that it does not really matter whether
the foundation of a theory of life is well and truly
laid. They think that a flaw in the construction
of an aeroplane may be fatal; but they do not think
that a flaw in our theory of life can be fatal. But
in truth the difference between the two cases is
only one of degree. A flaw in the construction of
an aeroplane may endanger the life of one man;
it may determine whether at a particular moment
he will live, or be dashed to the ground. But a
flaw in our conception of hfe may endanger the
whole of humanity, and condemn it to an existence
from which the sudden end of the airman would be
a merciful deliverance. For error in the construction
of a machine a man may have to pay down; at
any rate, little credit is allowed. For error in the
interpretation of life much longer credit may be
allowed, but in the end the bill must be met; and

in the long interval it may have grown to such a
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magnitude that it cannot be met. For the first
error men pay with their body or out of their pocket ;
for the second with their soul. Life will revenge
herself mercilessly on man if he does not try to
understand her, and order his life on the basis of
that understanding.

4a

CHAPTER III

‘i

HE Mosaic account of the origin of the various

forms of life which inhabit this planet is re.
jected by biologists of the present day on

two very different grounds. The first is that the
fossil remains of animals which have lived in past
ages, some of which have become extinct whilst
others have not, and the relation borne by the
sequence of these ancient forms to the successive
layers of the earth’s crust, compel us to believe that
the present forms of life have arisen by the gradual
modification, in difierent directions, of pre-existing
types. We have thus arrived at a pictorial con-
ception of evolution in the image of a tree, which
split early into two stems, the animal and vegetable
kingdoms. In this picture the earliest forms of
life, whatever they were, are represented by the
roots; the origins of the great groups of the animal
and vegetable kingdoms, respectively, are repre-
sented by the springing of the main branches from
the main stem; and the species of the present
time are represented by the leaves. There is no
evidence from fossils of the common origin of the
great groups from a single ancestral form. But we
have no need to fathom such deep recesses of the
past; it will be quite as much as we can manage

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if we try to understand the changes which have
taken place in so relatively brief a period as that
occupied by the origin of a handful of new forms
from their parent stock. This, then, is the first
ground on which the Mosaic account of creation
has been rejected by orthodox biology. It is
a ground of fact, and in my opinion it is firm
ground.

The second ground on which the Mosaic account
has been rejected is a philosophical one ; and although
at first glance it appears, by reason of its use-worn
surface, to be firm too, it is, in point of fact, a verit-
able quagmire which has led many an unwary one
to a disastrous end. This second ground is that
the Mosaic account of creation must be untrue
because it is anthropomorphic. Anthropomorphism,
strictly speaking, means the endowing of a God with
the form of a man. But the meaning of the word
has been enlarged at both ends. It has, very pro-
perly, been extended at the human end to the
endowing of God with attributes which are more
essentially human than the mere shape of man—
namely, the way in which man does things, and
the kind of things he does. It has also been enlarged
at the “‘ endowed ” end so as to mean the endowing
of anything, usually some non-human living thing,
with anything human. The extension of the word
at this end came about, during the nineteenth
century, part passu with the growth of a disbelief
in God, especially amongst men of science. There
was no god for them to endow with human attri-
butes. It was a pity that a good long word like
anthropomorphism should be wasted. So it was

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used to mean the endowing of anything non-human
with any human attribute. You must not say
that the lark sings for sheer joy, because that is an
anthropomorphic interpretation of the song of the
lark. You must not say that the protective colora-
tion or habits of any animal are the result of in-
tention or design in any form, because that would
be an anthropomorphic interpretation of the pheno-
menon. Any ascription of purpose or intention,
intelligence or design, to a non-human animal is
condemned at once by contemporary orthodox bi-
ology on the ground of its radical anthropomorphism.
It is true that purpose, intention, intelligence and
design are attributes of man. It does not follow
from this that they are attributes of man only.
Yet this conclusion is the central idea of modern
biology, the idea that the structure, activities and
development of the organism can be explained in
terms of physics, chemistry and mechanics, and
that the evolution of life is explained not by in-
telligence, design, purpose or intention, but simply
and as it were automatically by the theory of
natural selection.

Before we turn our attention to the theory of
the organism and to the theory of its evolution,
it will be well to examine more closely the way in
which the mind has been led astray by the word
“‘anthropomorphism ”’; for by such an inquiry we
shall arm ourselves against similar deception prac-
tised by other words.

The great length of the word, and its constant
repetition, may in some degree account for its

impressjve effect and for its anesthetic influence
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upon the critical faculty. But be this as it may
—and I intend it as no more than a tentative sug-
gestion—there can be no doubt that the word
anthropomorphism affords a very good instance
of the baneful effect which a word may have upon
the course of thought. In its original restricted
signification, in which it meant the endowing of
God with the form and habits of man, it certainly
denoted a grave intellectual misdemeanour, and the
epithet anthropomorphic, which very accurately
described this process, was rightly regarded as a
stigma. But those who were responsible for the
extension of the meaning of the word at the
“endowed ”’ end, for applying the word anthropo-
morphic to an entirely different thing—the grant-
ing of intelligence, purpose, design and human
attributes in general to non-human animals, in order
to stigmatise a concession to the “lower animals ”’
which was repugnant to them—were the uncon-
scious perpetrators of a successful fraud. One of
the easiest ways to convince an audience of the
untruth of an idea you wish to disprove is to apply
to that belief a word which has already been brought
into discredit and obloquy. If you can persuade
the audience that the word fits, the trick is done,
In the case of the word anthropomorphism the
audience needed no persuasion ; they hated the idea
that an animal had a soul, many of them hated the
idea that they themselves had a soul; they liked to
think of the organism as a machine, they liked their
mechanical theory of evolution, and they liked a
long word. The belief that a non-human animal

has an intelligence at all comparable to their own
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was branded with the word anthropomorphic, and
flung into the ash-bin of exploded superstitions. It
was not argument which effected the temporary
expulsion of this belief; it was abuse. It was the
very essence of abuse—which is calling a thing
names. Happily, it had all of its ineffectualness
too. Another abusive biological epithet is the
adjectival form of the name of the great French
naturalist, Lamarck. Lamarck’s theories may have
been farther from or nearer to the truth than sub-
sequent theories of evolution, but the prevalent
custom of thinking that any theory or idea can be
placed once and for all on the Index of Science by
merely calling it Lamarckian is founded upon the
theory of abuse, and results in the confusion of
the mind. The source of the trouble is inattention
to the problem of the relation between the word and
its meaning. The word itself does not change,
but its meaning does. And unless a sharp eye is
kept on the wanderings of the meaning, great con-
fusion may result from the undiscriminating use of
the word. Many people are irritated by the state-
ment that one does not understand the sense in
which they are using quite a common word; the
reason is either that to them each word has its
meaning tightly and securely attached to it; or,
if they think the meaning has a certain freedom of
movement, they avoid the problem of the relation
between the word and its meaning as a difficult one
(which it is); or the problem of this relation is not
present to their minds at all, they do not dissociate
word and meaning, and they say in a huff, “I

suppose there is no such word as anthropomorphic.”
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The part played by words, however, in deter-
mining the course of human thought is a minor
though by no means a negligible one; but that
which has chiefly directed its course is the set of
habits with which the human mind began, and
especially those which it developed during its
acquisition of control over external matter.

Let us see to what extent our modern conception
of the organism and our theory of the evolution of
life are what the early schooling of the mind would
lead us to expect them to be.

To deal first with the organism. It was well-
nigh inevitable that the human mind, in casting
about for a conception of the organism, for an
explanation of its activities, should light upon that
one of its ofispring which, though not its firstborn,
was the apple of its eye—the machine. At any
rate, whatever else might have happened, this is
what has happened. René Descartes, the father
of physiology, the science whose function it is to
discover the causes of the activities of animals
(and plants too), was the author of the mechanistic
theory of the organism. The essence of this theory
is that a living thing does what it does because it
is made in the way it is made. The function of
an organ is determined by its structure. If we could
know everything about the structure of an organism,
we could predict how it would behave in response
to any imaginable set of stimuli. The analogy used
by Descartes to illustrate his theory of the organism
is well known. He compared the human body to
one of those grottos, devised for the amusement

of princes, in which there were waterialls and foun-
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An Introduction to a Biology

tains, booby-traps and mechanical figures of men
which played mock musical instruments, all supplied
and worked from an office in the centre of the garden,
from which pipes radiated to the various displays,
and in which sat the hireling who, by turning on
one tap, could turn such and such a fountain on, or
by turning another make a mechanical figure play a
fiddle. The various activities of the whole appara-
tus were determined by the diameter of the pipes,
by the way in which they were fitted into the water-
falls and figures, by valves in them, and by any
ingenuities the inventor chose to devise in them.
The man in the central office only had to turn the
right taps or levers to direct the water in the desired
channel, and, provided there was no leakage, and
the joints and wheels were well oiled, he could
make any part of the system perform as he wished.
The various parts, and the whole, of this system
did what it did because of the way in which it was
made. If the mechanical ’cello-player was served by
the same pipe as that which worked a neighbouring
fountain, he had to play when this fountain played.

Descartes compared the nerves (which he believed
to be hollow) in the human body to the pipes in
such a grotto, the animal spirits (which he believed
to be gaseous) to the water which drove the system,
and the muscles and limbs to the various displays.
The entrances of the tunnels in the nerves into the
brain were guarded by doors; and when the body
was in a state of rest the animal spirits were pent
up in the cavities of the brain; but when a stimulus
was received from the outside, it was transmitted

along a nerve to the brain, the doors guarding the
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An Introduction to a Biology

entrance to the nerves supplying those muscles
which were required to be set in motion were flung
open, the animal spirits rushed out along the nerves
and set the muscles in appropriate action. The
essence of this explanation of the performances of
the human body is that the body is regarded as a
machine. The manner of its action is the result
of its structure. It is a theory of the living thing
which could not but be immediately intelligible.
When the human mind invents or encounters the
mechanistic theory of the organism, it is confronted
with an apparition which it at once recognises as
the darling of its adolescence and the symbol of
its power—a machine. No wonder it welcomed the
theory with open arms.

§ 2
If we look a little closer at the theory we shall
see that it is a materialistic one too. As in the case
of the machine all action is the result of the form
of the solids of which it is made and of the motive
force acting upon its different parts, so in the case
of the body, according to this theory, all action,
however complicated, is the result of the form of
the matter of which the body is made—e. of the
gross structure of the muscles and limbs and the
delicate structure of the nerves, and of the inter-
action of the chemical juices which it contains. It
is a materialistic conception of the living thing
because it means the belief, held by the great majority
of biologists at the present day, that all the mani-
festations of life are capable of being expressed in
terms of matter.
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An Introduction to a Biology

It is true that Descartes endowed the human
body with a soul; but it is probable that he did
this to avoid trouble with the ecclesiastical author-
ities. His placing of the soul was a pleasant fancy ;
he put it in the pineal body because that was the
only unpaired structure in the brain, and he called
the two diverging strands of nervous tissue which
extend downwards from this body the habenulae,
and thus gave the picture of the soul as a coach-
man, perched up on his box, with his reins between
his fingers, driving with a cheerful confidence that
restive team, the human body.

But to the non-human animal Descartes did
not vouchsafe a soul. The orgy of vivisection which
followed the enunciation of the mechanistic con-
ception of the organism was justified by those who
took part in it on the ground that the cries of their
victims were no more than the sounds produced by
the disruption of machinery. The difference between
the noise produced by kicking a dog and kicking
a tin can, according to such men, is due to the differ-
ence between the structure of the dog and the con-
formation of the can. But the cause of the noise
in the two cases was the same, the application of
the requisite stimulus to an arrangement of material
particles ; whether such arrangement take the simple
form of a tin can, or assume that complexity of
structure which is found in the familiar mechanism
to which we are accustomed to apply the name of
dog.

Modern Biology, the lineal descendant of, and
so personally identical with, the mechanistic con-

ception let loose by Descartes about two centuries
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An Introduction to a Biology

ago, professes to have explained many vital pheno-
mena in terms of matter—that is to say, in terms
of physics, chemistry and mechanics—and it holds
out to those who wish to embrace it the hope that
in the course of time most, if not all, of the mani-
festations of life will be interpreted in terms of
matter.

It is evident that in this philosophy of life there
is no place for the soul. Modern Biology has in this
respect gone one better than Descartes. It denies
a soul not only to animals other than man, but to
man himself. The biologist throws a sop to those
who cling to the belief that man has a soul. “ We
have now,” he says, “‘ a scientific conception of that
to which the term ‘soul’ used to be applied. Ii
you wish to continue the use of the word ‘ soul,’ you
must not mean any more by it than the sum-total
of the activities which are the result of the structure
ot that complex mechanism, the human body.”

According to the scientific view, it will be seen,
the soul may be used as an aggregate term for the
activities of the various parts of the body, especially
the brain. The structure of the matter of which
the body is made and the chemical interaction of
its gases and juices are the cause of these activities,
Matter is the master—the sole determining cause ;
the soul is only permitted to exist on sufferance,
and is reduced to the level of a mere symptom.

But the mechanistic explanation of the activities
of the organism will be seen on careful inspection
to be a very shallow explanation. Mechanism is
certainly the proximate cause of certain simple forms

of vital activity, just as the structure and mutual
87

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An Introduction to a Biology

relation of the parts of a man-made machine are
the proximate cause of the performance of that
machine. But the structure of a machine is no
more than the proximate cause of its activity.
Structure is only one stage behind action in the
causal sequence. True, if the machine were built
differently it would act differently; but that does
not make the build of the machine the explanation
of its activity. The explanation of the performance
of a machine surely les deeper than its structure,
and is to be sought in the idea of the machine as
it gradually took shape in the mind of the man
who invented it to fulfil a particular purpose. May
not, then, idea, intention, design, purpose be the
explanation of the mechanism which we perceive
in the organism? The whole trend of current
biological thought is to give an emphatically nega-
tive answer to this question. It is not that the
modern biologist shrinks from probing deep; on
the contrary, he thinks that he has not only touched
bottom, but that the foundations of his biology
rest upon bedrock itself. But is it not possible that
the sensation of security which he thinks is due to
his touching bottom is really due to the fact that
he feels at home with a machine? Is it likely
that man has fathomed the depths of life? It is
more likely that his sense of security is an illusion.
Man treading water on the ocean of life is more likely
to attain to a sense of security by coming to think
that he is trundling a bicycle than he is by actually
touching bottom.

But if mechanism is not the explanation of the

organism, what is the alternative view? If the soul
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An Introduction to a Biology

is not the ageregate symptom of the structure ol
the parts of the body, what is it? The alternative
view is that the form of the body is the effect of
the soul; that matter is subservient to spirit; that
structure is the result of activity, and not activity
the result of structure. Those who hold this alter-
native view do not think that the mechanistic ex-
planation is false; they believe that it gives a very
true picture of the proximate causes of the mechanical
devices made use of by life. They do not deny that
a great number of vital processes can be explained
in terms of physics, mechanics and chemistry ;
life, they admit, uses matter to achieve its ends ;
but they believe that there is behind these material
phenomena which we are beginning to understand,
something which is the cause of these phenomena,
and which we do not yet even dimly understand.

This, then, is the problem of life as it presents
itself when we address ourselves to the theory of
the organism. Is the soul a mere aggregate symptom
of a mechanism—the body? Or is the body not
rather the instrument of the soul ?

[The MS. breaks off at this point.]

89

I

Appendix to “An Introduction to
a Biology ”’

Mendelian Practice in the light of Bergson’s
Biology?
I

THE boundary of the territory of biology marches with
that of the science of agriculture at one point, or rather
in one region, as does the boundary of Germany with that
of France. In this region the academic science of biology
touches the practical science of agriculture. And this con-
tact has been to a great extent brought about by the
development of the ideas of heredity which we owe to
Mendel.

But on its other frontier the territory of biology has
recently come in contact with that of philosophy. This
contact has been effected by the work of M. Bergson; and
it has to be confessed that the reception of this friendly
invasion has been a sullen, and in many cases a peculiarly
offensive defensive, so that the only success hitherto achieved
by M. Bergson in the ranks of the biologists has been a few
prisoners here and there. This, in my opinion, is the great-
est event, so far, in the history of thought in the twentieth
century: the realisation by a philosopher—and a philo-
sopher who has already captured the imagination of the
imaginative section of mankind—the realisation by a philo-

1 From a paper read to a joint meeting of the Agricultural Discussion
Society and the Scientific Society, Aberdeen University, January 15th, 1915.

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An Introduction to a Biology

sopher that he must take into account the essential facts of
life, and especially the phenomenon of the growth of life
from its birth on this planet—the phenomenon, namely, of
evolution. But M. Bergson does more than this: he is the
first philosopher to insist that the philosopher must take
into consideration that mass of theory and fact which we
— eall Science.

Kant, it is true, insisted on the absolute necessity of a
familiarity with Science to the philosopher. But Science to
Kant meant only mathematical science. From Kant’s time
to the present day Science in all its branches has advanced
with such rapidity that it has become more and more diffi-
cult for the philosopher to keep pace with it and to assimi-
late it. The result has been that the gulf between science
and philosophy has become ever wider, and the philosopher
has become more and more concerned with the theory of
knowledge and less and less with things known.

So complete had this unnatural estrangement become
that when in 1859 Charles Darwin finally, after a century
of unsuccessful efforts by Bufion, Erasmus Darwin, and
Lamarck, succeeded in persuading mankind to swallow the
pill of evolution by gilding that pill with the materialistic
theory of Natural Selection—so complete, I say, had the
estrangement between philosophy and science become that
when the most far-reaching of biological generalisations
was formulated and accepted—I mean the doctrine of evolu-
tion—philosophy paid no heed.1 Not until the publication
of M. Bergson’s “ Evolution Créatrice” was the doctrine
of evolution admitted into the circle of philosophy. Nor
was the admission of this new-comer a mere formal and
belated honour to a distinguished foreigner. M. Bergson
incorporated evolution into the very fabric of his philo-
sophy. It might almost be said that he made evolution
_ the foundation of his philosophy. The stone which the

1The Author did not forget Herbert Spencer when he wrote these
words, though he may have forgotten Hegel.—Eb.

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An Introduction to a Biology

builders rejected the same has become the headstone of
the corner.

What, you may ask, has this to do with agriculture ?
In my opinion, a very great deal—in a general way and in
a particular way.

In a general way—viewing the continent of knowledge
from a point higher up than an aeroplane can get, but not
so far off as the moon—we have seen that the territory of
biology has extended its western frontier and has grown
into very intimate contact and union with the neighbouring
territory of the practical science of agriculture; and on its
eastern frontier biology marches with the territory of phi-
losophy. Now it is true that the results of this latter
contact have not so far been encouraging. Biologists have,
with few exceptions, rejected M. Bergson’s speculations as
fanciful and vain. The materialistic doctrines of orthodox
biology have so coloured thought that a man can get up
and say, ‘‘ War is good: I can justify this statement biologic-
ally : the law of the stronger holds good everywhere: those
forms survive which are able to procure themselves the
most favourable conditions of life and to assert themselves
in the universal economy of nature.” That is Bernhardi’s
statement of the doctrine of Natural Selection. J think it
is the best concise statement of it that there is. Bernhardi’s
biological justification for war is based on the materialistic
doctrine of Natural Selection.

The history of biology in the nineteenth century is the
history of the attempt, doomed to failure, as I believe, from
the outset, to express vital phenomena in terms of matter.
We are beginning to see what a horrible failure it has been ;
and I believe that the biologist, if he is to succeed in giving
an approximately correct interpretation of life, must, to
a large extent, begin over again and follow up the clues
given by Samuel Butler and Henri Bergson. If, then,
biology is to be affected by the vital philosophy of Bergson
(and I for one believe that it is going to be so profoundly

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An Introduction to a Biology

affected by it that the course of biological speculation in
the near future will be largely determined by that philo-
sophy) it behoves us to consider how that philosophy affects
biology on its applied side.

I admit that there is a prima facie justification for the
question which must have occurred to many of you: “Ti
biology has only just begun to be touched by this new philo-
sophy on one side which we called its eastern frontier, it is
not very likely, is it, that the extreme, opposite side of
biology—its applied side—will be affected by that wiae
sophy already 8

But, in point of fact, it happens that the particular
department of biology upon which at present most light
seems to be at once thrown by Bergson’s view of life, is the
general significance of the Mendelian phenomena. And, as
you are aware, it is the principles deduced from these phe-
nomena which have been offered by the biologist to the
practical breeder as a key to all, or most of the problems
of breeding. And this brings us to the consideration of
what I meant by saying that this new philosophy has a
bearing on the science of agriculture in a particular way.

Our next business, therefore, is to consider what are
the essential features of Bergson’s view of life. Bergson
believes that life is, in its essence, a thing which flows, a
stream which gathers experience as it flows onwards, ex-
perience which in the case of man is never lost but always
retained. We carry with us all of our past, and this past
is always liable to crop up in our psychic life. A rolling
stone gathers no moss. That is because a stone is a lifeless
thing. But a living thing whose real life is made up of its
experience is like a snowball which is rolled in the snow ;
it increases, as it is rolled, with the snow that it gathers,
until it becomes big enough to make a snow man of. This
flow of our psychic life is regarded by Bergson as that real
time which we live and in which we move and have our
being, as opposed to the mathematical time which is a mere

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An Introduction to a Biology

abstraction of the human mind. Our very existence, accord-
ing to Bergson, is Time. I need not labour the point that
our very existence, our real being, is in essence a flow.
Anyone who has devoted himself closely to the study of
his fellow men, or of himself, must be aware that man’s
psychic existence is a flow of moods like the procession of
shadow, rain, and sunshine across a landscape on a windy
day.

Now if we hold a mechanistic interpretation of life—
in other words, if we believe Natural Selection to be the
explanation of evolution, we believe that the changes which
have taken place in the habits and, in general, the actions”
or activities of animals and plants have been preceded by
structural changes in the organs (I might almost say the
parts of the machines) which performed those actions.
According to this view, changes in form lead the way;
changes in activity follow in their wake.

But if you hold a vitalistic interpretation of life, as
Lamarck did, and Butler did, and Bergson does, it is just
the other way. That which leads the way is changes in
activity or attempted action; that which follows behind
(because it is brought about by this action) is changes in
the organ which attempted to perform the action. Now
we know that the more often an action is performed the
more fixed does it become. And if we believe that the
shape of an organ becomes gradually fixed over the course
of countless generations by the repetition for myriads of
times of a particular action by that organ, then we believe
that the fixation of that character is due to the repeated
performance of an act by the organism which possesses it ;
which performance is an integral part of the very life of
the species; which life is the stream made up of the suc-
cessive generations, i.e. the time lived by that species. In
other words, Time has everything to do with the fixation of
a character. The longer the action, which is the function
of a given organ, has been performed, the more fixed will

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An Introduction to a Biology

the character of that organ be. So much then for the
bearing of Bergson’s conception of life on that most impor-
tant of biological problems, the determination of the causes
of the fixation of a character.

Now there is another aspect of this view of life to which
I have already referred. It is that this stream, which is
the very essence of life, is a perpetually widening stream ;
that something new is being added to it all the time. An
essential feature of life according to Bergson is that in its
growth (or its flow) it is perpetually elaborating the abso-
lutely new. So essential a feature of life does Bergson
regard creation by life that he has embodied it in the appar-
ently paradoxical and brilliant title of the work in which
he deals especially with evolution—“ Evolution Créatrice.”
The saying that there’s nothing new under the sun expresses
that view of change which is perfectly true of non-living
matter, namely that change consists merely in the redis-
tribution of already existing elements; a redistribution
which often, of course, produces an impenetrable illusion
of change and of the creation of something new. Never-
theless, it is an illusion; and we are thus led to the follow-
ing conclusion with regard to change in unorganised, 1.e.
non-living matter: that no more is got out in the effect
than was put in in the cause. You put pigs into the machine
at one end and you get sausages out at the other. Pigs
are not sausages, nor sausages pigs. You have the illusion
of change; but, in reality, all that has happened has been
a redistribution of elements. When, however, we look at
change in the domain of life we are in the presence of the
continual creation of the absolutely new. More is got out
in the effect than was put in in the cause. More 2s got out
in the end than was put in in the beginning. So far as this
planet is concerned, therefore, we must relegate the saying
that there is nothing new under the sun to the limbo of
exploded doctrines. For this planet has produced that
wonderful thing called life; and where life is, this saying is

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An Introduction to a Biology

not true. If for old acquaintance’ sake we wish to retain
the saying in some form we may say that there is nothing
new i” the sun, where the conditions for the existence of
life do not obtain.

There is a third feature in which life differs from un-
organised, i.e. non-living matter, according to M. Bergson,
namely that in the performances of living things there is an
uncertainty which is such that these performances cannot
be predicted mathematically. Here is a feature in which
life differs profoundly from unorganised bodies, the move-
ments and behaviour of which can be predicted with
mathematical precision.

We now come to the fourth and last aspect of Bergson’s
view of life to which I wish to draw your attention. I have
already said that the history of biology in the nineteenth
century is the history of the attempt to explain the phe-
nomena of life in terms of chemistry, physics, and mechanics.
And you must already have gathered from the whole tenour
of what I have said that I agree with Bergson in thinking
that this attempt will not be successful. I believe that the
living thing is something far more than a highly complex
machine filled with a lot of chemicals. How, then, you will
ask me, do you account for the great measure of success
which has attended the application of chemical, physical,
and mechanical principles to the solution of biological
problems? The answer I would give is as follows. I do
not for a moment deny that the problem, which confronts
the organism, of the getting rid of waste products, or of the
secretion of pigment, or the manufacture of bone, is in part
a chemical problem, or that the mechanism of the control
of the temperature of the organism is a problem which can
be expressed in physical terms, or that the child draws in
its mother’s milk by mechanical means. But I do not believe
that the soul is nothing more than a conveniently brief
term for the sum-total of the activities of the nervous
system. Surely it is the other way round: the nervous

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An Introduction to a Biology

system and all it controls are the elaborate instrument of
the soul. I do not deny for a moment, therefore, that the
organism employs physical, chemical, and mechanical means
to carry out its work. But if you think that when you have
described these means you have interpreted life, it seems
to me that you are resting when your work has only just
begun. You have not explained why a baby sucks at its
mother’s breast when you have described how it does so
in the terms of the village pump.

If we confine ourselves to the chemical activities of the
organism we may compare, as Bergson compares, the
organism to a retort, and its various juices to the contents
of that retort. The retort corresponds to the essentially
vital part of the organism and the contents to the inorganic
substances in its composition. Doubtless, it would be diffi-
cult to draw a hard-and-fast line and say where, within
the organism, retort ends and contents begin. But the
comparison is only intended to be a rough one and to draw
a general distinction, not a sharp line, between the essen-
tially living parts of the body to which chemical principles
do not apply; and those parts, or rather contents, of the
organism which are not one with the most vital part of the
organism, i.e. its individuality (or soul), and which, like for
instance cartilage or chitin, or bone or pigment, are the
same over a long series of animals. These parts, whether
they constitute the scaffolding, like bone, or the clothing,
like pigment, we may regard as separable or detachable
elements in the body, which do not enter into any close
union with the essential life of the organism. With regard
to pigments, these constitute, as it were, the outermost,
the most non-living layer of the not living parts of the
organism. They are limited in number, like the paints on
the painter’s palette ; though the variety of pictures which
the animal or plant can paint with them on its own wings or
petals is without end. It is the picture which it paints, the
type of its species, which is individual and unique and

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An Introduction to a Biology

alive and part of its very being; the pigments with which
the picture is painted are dead and might just as well have
been used, and of course have been used, by other species
to paint different pictures. Bergson’s analogy between the
organism and a retort does not appear to me to be a perfect
one, because we are apt to gather from it that the distince-
tion to be emphasised is between inside and outside, whereas
it is, of course, between essentially vital and not-essentially-
vital, or rather not-at-all-vital, in fact dead. And we have
just seen that some of the chief non-living constituents are
the farthest outside, namely, the pigments to which the
term “contents” does not apply at all.

Let us now re-state concisely the four main conclusions
to which a consideration of M. Bergson’s philosophy has
led us :—

1. Time is the essential factor concerned in the fixa-
tion of the characters of organisms.

2. Life is perpetually creating the absolutely new;
more 7s got out in the effect than is put in in the
cause.

3. The performances of living things cannot be pre-
dicted mathematically.

4. The organism consists of an essentially vital part
and of non-living constituent parts.

Now look at the Mendelian principles of Heredity, which
are offered to the breeder as an instrument of great value.

(1) One of the chief claims of the Mendelian is that
his theory gives, for the first time, a coherent scientific
explanation of the fixation of characters. Fixity of a par-
ticular character, according to the Mendelian, is due to
the fact that the organism which bears that character was
the result of the union of two germ-cells, both of which
contained the factor for that character. In Mendelian terms,
the organism was homozygous for that character. In-

9S

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An Introduction to a Biology

stability or unfixity of a character, on the other hand, is due
to the fact that though one of the germ-cells which pro-
duced the organism bearing the character in question con-
tained the factor for that character, the other germ-cell
contained the other factor of the pair. In Mendelian terms
the organism was heterozygous for that character. Fixa-
tion, that is to say, is due, according to Mendelian prin-
ciples, not to the continued breeding to a particular standard
over a great number of generations, but to the union of
germ-cells bearing the appropriate characters. In other
words, time plays no part in the fixation of a character. .

(2) Another idea essential to Mendelian principles is
that all that the breeder can do is to effect re-combinations
of existing characters. The creation of new characters has
no place in the Mendelian scheme.

(3) Lastly, the Mendelian principles render possible for
the first time the prediction of the result of the union of a
given pair of individuals, in cases which have already been
subjected to Mendelian analysis; and not only this, but the
numerical ratios in which the various characters will appear
amongst the offspring resulting from the union can also be
predicted.

If these conclusions be compared with the first three
conclusions arrived at after a consideration of M. Bergson’s
biology, it will be seen that they are flatly contradictory.
His main conclusions with regard to life are untrue of
Mendelian characters. This may mean either (1) that M.
Bergson’s conclusions are ill-founded, or (2) that the Men-
delian characters are dead or, at any rate, appertain to the
least vital parts of the organism. I believe the latter alter-
native to be nearer the truth. If it is nearer the truth, we
have, I think, a clue which will enable us to relegate the
Mendelian characters to their true position among the
characters of living things; and a suggestion which may
enable us to determine, without experimentation, which
characters are likely to behave in a Mendelian way in heredity

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An Introduction to a Biology

and which are not. And it would seem, in general, that
Mendelian characters are to be found amongst the contents
of the retort and are not exhibited by the retort itself.

II

Notes oF A LECTURE GIVEN IN JuLy, 1914, aT THE
GRADUATE ScHOOL OF AGRICULTURE, HELD AT THE
UNIVERSITY OF Missourr, CotumBia, Missouri }

THERE is a fundamental difference between character of
species and character of varieties.

According to De Vries a varietal character is one which
may be borne by any plant or animal. A species character
must be borne by all individuals.

Character of a species is the ensemble of characters and
something unique. |

It is like a man’s written signature. A varietal character
is like a stamped signature. It may be stamped over a large
number of individuals.

Varietal characters are all that will be possible of isola-
tion as unit factors ; e.g. wrinkledness of peas is also stamped
on corn: it is not a species character.

De Vries thinks varietal characters are Mendelian. Prob-
ably Mendelian characters are varietal characters.

Four general conclusions with reference to Mendelian
results :—

(1) Time is no factor.
(2) Nothing is obtained that is not put in.
(3) Varietal characters are unit factors.
(4) Mathematical expressions can be applied to Men-
delian phenomena.
Has time anything to do with the fixation of a character ?
Experiment with peas to test this.
There are two varieties of pea-flower in regard to colour :
the white pea-flower (the commonest) and the pink pea-

' Vide supra, Preface, p. xvii.
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An Introduction to a Biology

flower. These crossed give a purple flower, the ancestral
form. The experiment explained, on the basis of two sets
of factors, thus :—

B = factor producing blue only in the presence of factor for
pink, P;
hence Bp = white, and therefore BPpb = purple.
White pea-flower Pink pea-flower
Bp x Pb
purple ancestral form
BP pb

ees

PPB, PpBB,

PPBB, PPBb, PpBB, PpBb PPbb Ppbb ppBB, ppBb
PPBb, PpBB, PpBb Ppbb ppBb, ppbb
——_— eel

Purple 9 Pink 3 White 4

This is a convenient way of expressing the results, but
it does not really signify anything as to what is actually
going on in the plant. If four whites really have these com-
binations of factors, then it may be tested by crossing the
whites with a homozygous pink, and theoretically the results
should be :—

PiInK (homozygous) X WHITE PURPLE PINK
1. PPbb x BBpp 100% —
2. PPbb x Bbpp 50% 50%
3. PPbb x bbpp ~— 100%

This has been done with a small number of plants, and
is being repeated on a large scale by Darbishire. Darbi-
shire found that in the cross (2. above), PPbb x Bbpp,
the ratio was about 3:1 and not 1:1.

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An Introduction to a Biology

All that the 50:50 ratio shows, if it be true, is that the
Mendelian explanation only accounts for what is happen-
ing in gametogenesis of the second generation, and we
should not base a general conception of heredity on the
conditions obtaining in the second generation. Darbishire
obtained seeds from many sources, with the result that
pink by white always gave purple, which means that all
the white are BBpp, i.e. all carry blue in a homozygous
condition.

There are no pure whites on the market, if we accept
the Mendelian explanation.

Darbishire does not believe that this formula gives us
what is really happening. He believes that the union of these
two characters sets up a disturbance, causing them to fall
back on what they used to be, while later segregation occurs.

The degree of disturbance would be comparable to the
length of time the two strains remained isolated.

Darbishire has planned and is now continuing the follow-
ing experiment :—

Select pure pink with formula PPbb and pure white
with formula ppbb. Cross these :

PPO. oy 3X) > geeb

hg

pink.
Save these seeds, and in next generation make the same

Cross :
PPD RK ppp

e
oe
\
\

Q

If the Mendelian theory is correct, saving the seeds and

repeating this cross again and again should never give any-

thing but pink. However, if there is anything in the other
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An Introduction to a Biology

view, namely, that a disturbance occurs proportional to
the length of time of isolation of the two strains, then sooner
or later purple will appear. Darbishire predicts that this
is what will happen.

III

LetTerR FROM A. D. Darpisutre To M. Berason, of Decem-
ber 6th, 1912, accompanying a copy of his book “‘ Breed-
ing and the Mendelian Discovery.” }

LETTER FROM M. Berason To Mr. DARBISHIRE.

Villa Montmorency,
18 Avenue des Tilleuls,
Auteuil, Paris,

12) Dees: 18i2:

CHER MonsieuR,—Je tiens a vous remercier pour l’envoi
de votre ouvrage “‘ Breeding and the Mendelian Discovery ”
et pour l’aimable lettre qui laccompagnait. Quoique surchargé
de travail, d’occupations, et de préoccupations en ce moment,
je n’ai pu résister a la tentation de lire tout de suite le livre
jusqu’au bout, tant les premiers chapitres m’avaient séduit
par la précision et Pélégance de lexposition. Vous avez
bien raison de présenter cet ouvrage dans votre préface
comme nous donnant une vision immédiate des faits, sans
hypothéses interposées; mais cette vision, en raison méme
de sa netteté et de son caractére concret, suggére au lecteur
des hypothéses et des idées explicatives. Sur ces hypo-
théses vous avez eu la discretion de ne pas appuyer dans
Youvrage lui-méme; mais vous les formulez dans la lettre
si intéressante que vous avez bien voulu nvécrire. L’idée

1This letter, to which I have found many references in correspondence
and notes, has not yet been traced, M. Bergson, who has the letter in
his possession, promised to let me have it as soon as it could be found,
but it has not reached me in time for publication in the present volume.
I am greatly indebted to M. Bergson for his kindness in allowing me to
print his reply of December 12th, 1912, which gives an indication of the
contents of Mr. Darbishire’s letter.—Ep,

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An Introduction to a Biology

de voir dans V’hérédité mendelienne un phénoméne de
descente plutdt que de montée, et de considérer la domestica-
tion en général comme déclanchant certaines potentialités
de perte ou de destruction, est originale et suggestive au
plus haut point. Je souhaite que vous la repreniez et la
développiez tout au long dans l’ouvrage que vous projetez
@écrire sur lévolution1 En attendant je tiens a vous
envoyer, avec mes remerciements et mes compliments,

assurance de mes sentiments dévoués.
H. BERGSON.

IV
NOTES AND EXTRACTS

My attitude to the reader not that he must accept this as
logical necessity, but may if he like.

* * * *
Biology intermediate between painting and exact science.
* x ** *

The spoon, knife, and fork are organs which the civilian
has detached and put into the “pool” of the family or
restaurant. They are less detached from the soldier.?

x x * *

It may have been that curiosity operating through the
hand suggested the assumption of the erect posture. Ac-
cording to this view, it would not be the erect posture which
set free the hand, but the desire to use the hand which
suggested the erect posture.

* x * x

The explanation of the lathe is not its structure, but its
history.

* *k * x

Farseeingness of Germans, because intellect followed
lines of evolution of weapons.

1This refers to the work of which a fragment is here published, “‘ An
Introduction to a Biology ” (wide supra, pp. 1-89).

2 Several of these notes were jotted down while the author was under-
going training as a private soldier.

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An Introduction to a Biology

Description influenced by Interpretation. Hausmann
interpreted development of horse in terms of man.

Five nerves have always been described as going to
electric organ of Torpedo, because the original investigator
described five. There are four.

2 * * x

If all description were direct it would be bad enough ;
but most of it is copied. What an additional source of error
is here !

*k x ** 2

My dissociation between seeing and understanding:
Lying in bed, I discern an outline, blocks of light and shade.
I do not know which is light and which shade. I cannot
recognise the object. I cannot fit it into a category. Seeing
is remembering.

[Correlate my inability to interpret the shadow with the
Siamese-twinness of Description and Interpretation. ]

2* X *k *

A theory which touches reality at no point cannot be

disproved or proved by an appeal to reality.
x * * *

I see theories as balloons. Their makers inflate them,
their admirers over-inflate them; and they generally burst
from over-inflation.

x * x x

Those who prefer swimming out of their depth may
speculate upon first causes and on what happens after death.
But the biologist, whose business is the difficult task of
understanding life, must be careful to undertake a much
less ambitious and precarious task.

** * x **

Obvious reason for thinking in terms of opposites is that
it is thinking in terms of a struggle—perhaps the best in-
stance of the application in the conceptual sphere of habits
of thought contracted in the sphere of action.

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An Introduction to a Biology

We think of a thing in a straight line. So Natural Selec-
tion explains improvement: it does not explain divarica-

tion.
* * x *

To draw the line somewhere. . . . Of all forms of self-
expression drawing lines is the most inartistic and the least
satisfying.

x * x *

Matthew Arnold says, know what you want to say, and
say it as simply as you can. Strange not to see that the
idea does not fully exist until it is expressed; but as in
the eyes of the law a man’s life begins with birth, so an
idea dates its origin not from the moment of its first dim
conception, but from the moment when it was born, i.e.
literally expressed.

* * * *
The secret of —— is that she doesn’t externalise. She
cannot use a watch. She is the opposite of ——, e.g., who has

externalised himself in his museum and his library. None
of her interests are external. That is why she has such
power: she doesn’t dissipate it: she keeps it all in. If
one must externalise oneself, one should do it spiritually
through art or children.

* * ** *

“ Original.’ The sources of the Ock come from rain, but
only after that rain has passed through much earth. My
drawings come from reality, not direct—I never copy—but
through many days of my existence. Beethoven’s revela-
tion of life comes from life, but not only the life he has
lived in his own person, but from the life he has lived in
the persons of his ancestors extending back probably to
pre-human ones. A man cannot formulate a conception of
life from the conscious observations he has made during
his own lifetime. He must formulate and make conscious
what is already in him.

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An Introduction to a Biology

“The mantle of A falls upon B” means that B is the
next source through which what flowed through A will
flow out.

* ** ** *

There can be no laws of heredity: least of all of here-
ditary genius. Mendelian characters may not be free, but
mental ones probably are, and the production of genius
must be.

S * * +

Reason why facts of Biology are so specialised—the
desire to discover something new, e.g. description of new
species. But genius consists not in telling you something
nobody knew, but something everyone knows.

* * * *

Originality is the attribute of a man—like Beethoven—
who is an instrument in the hands of a power stronger than
himself, the spring through which a message is delivered.
It is the attribute of the work of the man or of the man
himself (for in the case of great men the man and his work
are one) who expresses for mankind what they have known all
along so deep in their hearts that they did not know they
knew it. Originality is the attribute of those men who are
born with the gift which they hand on to mankind.

But in current parlance the words “original” and
*‘ originality > mean the very opposite of this. Originality
is taken to be the doing of something new, or different from
the ways in which it has been done. “ Original research ”
means working in a new field and bringing to light facts
which have not been discovered before. It ought to mean
work which searches again into origins.

x x ** **

Life has got into the very hands least fitted to deal with
her—into those of glum octogenarians fondling dry bones

with their withered hands.
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An Introduction to a Biology

Why we like fire: the forms of flame are never repeated,
i.e. they possess the attribute of life.

Bs * * *

If you break the bone of your nose so badly that a
portion has to be removed, you can obtain a piece of bone
from another mammal and have it put in its place. But if
you should lose a part of your soul, a much commoner
accident, no such operation could be performed.

* #: * **
—’s saying, “‘ Pity poor D has done nothing.”
Have I? His idea that one must perpetually be publishing to
keep oneself in known-ness is like the cinema bridging over
gaps between successive moments. It is extension, not depth.

~

May 1, 1915.
To G. Herpert Turine, Esq., Secretary to the Incorporated
Society of Authors.

Dear Siz,—In reply to your circular of last month
with regard to the use of the cinematograph for educational
purposes, I write to say that I am strongly opposed to the
application of the cinema to the study of life, i.e. to biology.

The tendency to make the scientific lecture a sort of
music-hall entertainment which carries on the interest from
one moment to the next by “experiments” and “ lantern
slides,” and what not, at the minimum expenditure of effort
on the part of the listener, requires, in my opinion, no fur-
ther encouragement. The rdle of the cinema is to amuse
even when it covers amusement with the cloak of “ interest,”
and not to stimulate. The cinema encourages the natural
tendency of man to seek his pleasures and interest where
he has found his instruments, outside rather than within ;
but it takes us not into the souls of things, but into an
unreal, artificial region ‘‘ midway between things and our-
selves, external to things, external also to ourselves.” 4

1 Bergson, ‘‘ Laughter.”” Eng. transl., p. 154,
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An Introduction to a Biology

M. Bergson has expressed himself, in his Gifford Lectures,
on the Problem of Personality, very strongly on the lines
indicated above.

In short, I should regard the use of the cinematograph
in the teaching of biology as fraught with the gravest dangers
to the mind.

I am, yours faithfully,
A. D. DarBisHIRE,
Lecturer on Geneties and Demonstrator of
Zoology in the Uniersity of Edinburgh.

[Notes for a paper read to the Students’ Natural History
Society at the Royal College of Science, December 19th,
1910.]

The man of science, in announcing his conclusions, says
“the facts speak for themselves.” But facts do not speak
for themselves. They say what we make them say. What,
then, is the scientific investigator to do? Is he merely to
record facts and leave them to say what anyone who comes
across them chooses to make them say, or is he to make
them speak? In other words, is it the function of science
merely to record, or is its function to record and interpret
as well ?

I think an answer to this question can be attained by
first answering another question with regard to the function
of science. Is the sole function of science the elucidation of
truth ? I think it ought to be; but there is no question that
it is not. JI mean that many who genuinely believe that
they are engaged in laying bare the truth are certainly,
in many cases, doing no such thing; and, even when they
do accidentally provide a clearer vision of things as they
are, they are engaged in this work not solely because they
wish to get at the truth. They do wish to get at the truth,
of course; but that is only a symptom of the force that
drives the natural philosopher to construct his philosophies.

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An Introduction to a Biology

My thesis is that this force is the same as that which
lies behind poetic utterance of every kind, whether it reach
us through the eye or the ear. The masterpieces of art and
of science are both due to the irrepressible need for the
thing for which there is no better word than self-expression.
The heroes of science, as well as of art, have always ex-
pressed themselves by prodigious performances in the
imaginative sphere. “ But surely,” you may tmterrupt me,
‘“‘ Darwin’s work was great because it discovered the truth
about evolution.” Well, that is not my view; I do not
think he did discover the truth about evolution; he per-
suaded people to believe that evolution had taken place—
a prodigious feat. The great in science are not those who
discover new facts, but those who imagine things about
the facts discovered by others. This imagining of things
about facts is called detecting the principles underlying the
facts; but it is nothing of the kind, because there aren’t
any principles underlying them—and don’t you forget it.)

I am not now offering any opinion as to the desirability
of imagining things about facts; I am merely stating that
the great in science are those who have produced great
imaginative works, and not those who discover. Has any-
one here not heard of Darwin? How many of you have
heard of Giesbrecht? If you have heard the name of
Rothschild, it is not because a member of that family has
a world-wide reputation as an authority on fleas. .

You will gather that my theory is that science pro-
vides an opportunity for exercise in the imaginative sphere
just as music or painting does. There is one side of the
human soul which needs to express itself by creative work
of some kind; this may either be done through the medium
of those forms of art which appeal to one through the eye,
or those which appeal through the ear. I can perhaps give
you an idea of the general character of these poetic, Le.
creative utterances by showing you the attempts which I
made, at the age of about eight, at creative utterance. I

IIo

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An Introduction to a Biology

see in them many of the things which I now hear in Beetho-
ven’s music. Rushes, complexities, antagonisms, prodigious
effort, elemental fun; many of them cast in definite form
or design. [Drawings exhibited.] I expressed myself in
drawings because I could not in music; similarly I think
those who cannot go the whole length of obtaining satis-
faction from music obtain it from poetry, which is music
cast in words instead of notes. That is why those who
really make use of music do not read poetry, and that is
why Browning, the least sonorous of poets, was a great
lover of music, and Tennyson, the most musical in his
poetry, didn’t know a note.

And at last—here is my point—science itself is used as
a means of creative utterance; the joy a man of science
experiences in reaching his conclusions.! .

[From lectures on Evolution, delivered at the Royal
College of Science. ]

Evolution cannot be studied out of relation with, and
isolated from, the objects of human interest which surround
it. I can conceive of no more barren exercise than a study
of evolution which is not also a study of life. The two
studies cannot be conducted separately. In the future a
theory of life, like that of Coleridge, which is not also a
theory of evolution, will be of as little value as a theory of
evolution like that of de Vries, which is not also a theory
of life.

. . A theory of life is a much bigger thing than a
theory of evolution. Evolution is only one of the numerous
manifestations of vital activity; but it is that manifesta-
tion the study of which will help us most in attaining to
a true theory of life. Those of you who have read my
paper entitled, “Some Tables for Illustrating Statistical

1The MS. breaks off here.
res

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An Introduction to a Biology

>

Correlation,” may remember that I concluded it with the
observation ‘‘ Directly we can play with machinery we can see
how it works. Movement and change enable us to perceive
and to understand.” I think this represents a very general
truth about our relation to natural phenomena. And if you
agree that it does you will also agree that our best way of
attaining to a true knowledge of life is to study the pheno-
menon presented by life undergoing change, that is to say;
to study evolution.

Whatever may have been thought of any scheme for
improving mankind, whether physically or morally, put for-
ward before the time when a belief in evolution had become
general, the one thing certain about such a scheme is that
it belonged wholly to the realm of fancy. But now that a
belief in evolution has become current intellectual coin, the
hope of breeding a race of supermen has become more than
a Utopian dream, and the early years of this century wit-
nessed the foundation of a department of Eugenics whose
ultimate object is the amelioration of the race. The know-
ledge that we have not always been in the past as we are
now gives us hope that we may not always be in the future
as we now are.

. . The plasticity of the organic type is the one thing
which gives us hope for the future. Was there not some
prophetic significance of this kind in the words spoken by
Ophelia in her madness: “ They say the owl was a baker’s
daughter. Lord! we know what we are, but we know not
what we may be” ?

But Rome was not built in a day, and the change which
can be effected in a single generation will be infinitesimally
small. And though we cannot hold the extreme form of
belief in this plasticity which was entertained by Ophelia,
who quotes without comment, but as the context shows
with approval, the statement that the owl was a baker’s
daughter, we may effect some alleviation in the suffering

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An Introduction to a Biology

caused by the knowledge of what we are from the fact, now
established, that we know not what we may be.

.DARWIN AND THE ORIGIN oF SpeEctiss !

Darwin performed the gigantic task of forcing mankind
to believe in evolution. So great was this task that it seems
almost too much to expect that the theory by means of
which he effected this should be true as well. The mere
fact that the theory—Natural Selection—which attempted
to account for evolution could be understood, or, at any
rate, was soon accepted, by nearly everybody invites by
itself the suggestion that this theory gives a picture of the
causes of evolution which; at any rate, is not complete.
For it is not as if evolution were a simple matter; it may
be said that we know hardly anything of the factors to
which it is due. And the fact that we are all actors in the
evolutionary pageant renders it almost impossible for us
to visualise the process from a detached standpoint as the
master of a pageant does. This brings us to what seems to
us to be far and away the most interesting question which
can confront the student of life—namely, whether evolution
is a process of which a simple mechanistic explanation has
been discovered ; or whether it is not a mysterious process
which we are scarcely able to understand at all yet, but
which may, perhaps, be due to deliberate striving on the
part of the animals and plants which have taken part and
are taking part in it. And many will lean to the latter
interpretation, because they find it inconceivable that we
should know as much about so vast and complex and close
a thing as evolution as we should do if the mechanistic
explanation of it by natural selection were true.

Professor Poulton has presented his view of evolution
with such eloquence and enthusiasm that we feel almost

1 Extract from Review, ‘‘ Charles Darwin and the Origin of Species,”
by E. B. Poulton, F.R.S.—The T'imes Literary Supplement, Thursday,
November 25th, 1909.

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An Introduction to a Biology

forced to lay some stress on the existence of the other view
of evolution to which he makes no reference at all; that
is, the spiritual (as we may call it) view of evolution of
Samuel Butler, as opposed to the mechanistic one of Charles
Darwin. The problem of evolution will be brought within
range of attack by the man who provides an answer to the
question, Which comes first, effort or structure? Does a
dog scatter dust with his hind legs because in the past his-
tory of his race those dogs have been eliminated which
have varied in the minus direction with regard to the dust-
scraping capacity (which is presumably determined by the
molecular structure of a part of the brain) or for some reason
akin to that which prompts our sanitary habits (such as
they are) which we may perhaps never be able to under-
stand? The mechanist may object that these feelings in
us are the outcome of the structure of a part of the brain,
so that everything is ultimately referable to structure. This
may be. But an effort (or other manifestation of the spirit)
is none the less an effort for being expressible in mechanical
terms. And the question of the future will be whether evolu-
tion has been brought about by effort or by the elimination
of fortuitous structural variations.

SAMUEL BuTLer’s ‘“‘ Lire anp Hasir”’ ?
Perhaps the most conclusive proof, if one were needed;
of the arrogance of the human species is to be found in the
fact that the man who was the first to succeed in convincing
his fellow men of the truth of evolution was the man who
first refused to admit that the intelligence of the living
things themselves played any part whatsoever in bringing
about the changes to which evolution is due. Buffon per-
ceived the fact of evolution; so did Erasmus Darwin; so
did Lamarck; but they all believed that the purposive
efforts of the living things themselves played at least some
1 Book notice, English Review, March, 1911.
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An Introduction to a Biology

part in bringing it about; and they, likewise, all failed to
convince their contemporaries of the fact of evolution. Charles
Darwin threw the intelligence of the performers in the evolu-
tionary pageant overboard and put forward, as an explana-
tion of evolution, the theory of natural selection, which went
straight to the unimaginative heart of the mid-Victorian.

From that time evolution was accepted as intellectual
coinage, with ‘“‘ Evolution” on one face and “ Natural
Selection” on the other face of the coin. From that time
evolution became, in the most strictly literal sense of the
words, lifeless and hopeless: lifeless, because, according to
the theory of natural selection, living things have not evolved
by virtue of any of their essentially vital attributes; and
hopeless because, according to the theory of natural selec-
tion, no effort of ours can make our children better than their
fathers; and because the only way to fight our most for-
midable enemy, disease, is to expose ourselves to the risk
of contracting as many diseases as we can in order that
those of us who are susceptible to one or more of them may
be eliminated.

Evolution remained this automatic, lifeless thing until
1897, when “ Life and Habit’ appeared and put the breath
of hfe into its nostrils.

We read “ Life and Habit” in the spring of 1909. We
had been brought up in the school of Natural Selection ; our
lectures on Evolution began with Charles Darwin. Evolu-
tion as explained by natural. selection was a drab thing in
which we had to believe. The change wrought in us by read-
ing “ Life and Habit”? was miraculous. An extraordinary
change had also come over the living things we saw. They
appeared as they had never appeared before. They wore
an uncouth aspect, which was unfamiliar, and yet strangely
familiar, to us. They were alive. Evolution from that time
became a thing in which it was not a necessity, but a joy,
to believe.

About a year later the biological library committee of

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An Introduction to a Biology

one of our leading scientific institutions met. Of the large
number of works which it considered, one only was rejected
—Butler’s “ Life and Habit.” A Monograph of the Fossil
Barrabide was at once passed with subdued murmurs of
respectful applause. As were other works of like nature,
Life and Habit’ was not merely rejected: it became the
subject of merriment. One of the committee opened it at
random and exclaimed, “‘ Listen to this,” and read a sentence
in which “frog” and “soul” occurred. The suggestion
that a frog had a soul provoked roars of laughter. To be
acceptable to scientific orthodoxy you must not say that
a frog has a soul. If you do you will be greeted with
laughter. But if you say that a sea-urchin’s egg has a
psychont (which is only another word for soul) you will be
treated with deference. The future lies with those who
prefer the laughter.

No one denies the extraordinary interest of the Men-
delian discoveries. . . . But we hold that he must be a
very rash man who accepts without further question the
doctrine of gametic purity. Yet it is just im the sphere of
interpretation that the Mendelians are so certain. Once
- in this sphere, we can no longer be guided by facts—if we
were dealing with facts we should be in the sphere of dis-
~covery—but by “such things as our mind conceives.” And
one’s attitude should be one of continual, unceasing, and
active distrust of oneself. The attitude of the Mendelian
is different from this. He may reply that he is triumphant
only about his discoveries; but we must remember that
there is no fixed criterion by which we can say where dis-
covery ends and interpretation begins; and we must be
careful not to beg the question by defining discovery as that
about which there can be no doubt. . . . We think it
high time that the spirit which derives satisfaction from
the victory of one opinion over another should be swept from
science. There is no place for the party system in science ;

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An Introduction to a Biology

because it tends to make the triumph of truth the main
object and truth itself a secondary one. We are not arguing
that the Mendelian theory is untrue, but that the atti-
tude of anyone daring to say of anything “this is true”
should be apologetic rather than victorious.

[From a review, Nature, May 23rd, 1907.]

The most fruitful source of progress is a new way of
looking at things, and such new points of view result in
the destruction of old classifications and the need for new
ones. In biology, investigators will soon be classified, not
according to the group of animals or plants with which they
deal, but according to the particular phase that interests
them of the problem of the “‘ fundamental nature of living
things,” which is the ultimate goal of biological inquiry.

[From a review, Nature, August 3rd, 1905.]

This book is not written by a man red-handed, fresh
from an encounter with Nature. If his hands needed wash-
ing before he wrote, it was to remove the dust of books.
Would that the water could have removed the taint of
much reading also. The notion that the truth must be
sought in books is still widely prevalent, and the present
dearth of illiterate men constitutes a serious menace to the
advancement of knowledge. . . .

Earnestness is not a sufficient qualification for author-
ship.

[From a review, entitled ‘‘ Another Book on Evolution,”
Nature, 1911.] |

It would be a most fascinating task to trace the evolu-
tion of modern methods of dealing with the problems of
life. Differentiation has taken place so extraordinarily
quickly. The time is long past when one man can attempt
to grapple with the whole problem. Not only so, but the

II
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An Introduction to a Biology

time seems to be past when one man can even be inter-
ested in the whole problem. Evolutionists may be broadly
classified into those to whom the problem of evolution is
the problem of the origin of species and those to whom it
is the problem of adaptation. The keynote of de Vries’s
‘“‘Mutationstheorie” is the solution of the problem of
species; we even go so far as to say that this is the achieve-
ment of de Vries’s work. The logical conclusion, the com-
plete working out of the theory of natural selection, is
reached in Dr. Archdall Reid’s “ Principles of Heredity.”
The interest of the two authors is entirely different. De
Vries’s interest is in the origin of species, Dr. Reid’s in natu-
ral selection. Darwin’s interest was in both; if we look
no further than the title of his chief work we can see this—
“On the Origin of Species by Means of Natural Selection.”

The fact that these two interests have segregated, and
the way in which they have segregated, are both very sug-
gestive, and the direction in which they point is the same.
The fact of segregation suggests that the association of
the two ideas was unnatural, and that they were not cap-
able of union. The way in which they have segregated con-
firms this suspicion. For those who devote their atten-
tion to the question of species reject natural selection,
_while those who elaborate the theory of natural selection
find no support in the phenomenon of specific difference.
All possibility of a reconcilement between the divorced
ideas is put an end to by Meyrick, who probably knows
more about specific difference than anyone else. In _ his
handbook of British Lepidoptera he says that, in seeking
for the most suitable characters by which species may be
_ distinguished, those which can in any way be regarded as
useful to the species must be discarded without more ado.

It is not surprising that Darwin’s work should have
borne fruit which segregated in this way. The case is
thoroughly Mendelian. Darwin’s work was a cross between
a biological theory of evolution and a social and indus-

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An Introduction to a Biology

trial theory of competition. The hybrid, more vigorous
than either parent, took the world by storm. We are now
witnessing its posterity separating out more or less simply
into the two forms which were united in the beginning. Just
as every plant in the F', generation contains yellow and green
peas, and just as it is not until the next that there can be
found plants bearing only yellows or only greens, so Dar-
win’s interest was in the “ Origin of Species by Natural Selec-
tion,’ while now we find de Vries, who is absorbed entirely
with the former, and Reid entirely with the latter. .

The experimental method has its limitations no less
than its fascination. It is not merely a paradox to say that
in biology those things with which we can experiment most
are those which to the organism matter least. The reason
is that we are not the first to start experimenting. Nature
has been there before. For example, the range of continu-
ous variation in an organism may either be the direct result
of the constitution of the living substance, or it may have
been determined by the most stringent selection acting since
life dawned. If, therefore, we institute experiments on
variation—for example, the determination of the effect of
heat on the range of variation—we may either be studying
one of the simple properties of protoplasm or discovering
the limits within which natural selection allows the par-
ticular organism dealt with to vary under the conditions
of heat, e.g., to which we subject it. The really funda-
mental processes do not lend themselves to experiment.
That is how they have become fundamental.

[From a review, Nature, April 4th, 1907.]

Tue PRINCIPLES OF HEREDITY, WITH SOME APPLICATIONS.
By G. A. Reid.

The publication of this book marks an epoch in the
history of the relation between medicine and biology, inas-
1From Nature, December 7th, 190 .

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much as it is an embodiment of the recognition by medical
men that they depend ultimately for a precise knowledge of
nature on the professional biologist—who may or may not,
at the same time, be a medical man.

The book should be welcomed by doctors as contain-
ing in the earlier chapters a straightforward, though rather
brief, account of theories of organic evolution, and by
biologists as giving a very full account of the medical aspects
of these problems, and by both as an interesting collec-
tion, under the title of “The Principles of Heredity,” of
a mass of information and ideas connected with that
phenomenon.

The reader may object to the antithesis between medi-
cine and biology ; but will, we hope, withdraw his objection
when it is explained that all that is meant by it is the anti-
thesis between applied and pure biology. The recognition
by medical men of the value to them of the information
with which the biologist is able to supply them is unques-
tionably a good thing; yet it is a curious illustration of
the fact that a new movement of opinion cannot stand
isolated and alone, cannot be without consequences of one
kind or another, that one result of the popularity of the
entente between the doctor and the biologist may prove
harmful to biology, and through it perhaps ultimately to
medicine.

The danger is that the biologist pure and simple, the
man who works at his subject for the mere joy of investiga-
tion and discovery, may cease to exist. ‘So many workers
of this type are becoming applied biologists, whether they
be sporozoologists devoting themselves to malaria, students
of heredity to eugenics, or cytologists to cancer. We do
not, of course, complain of the application of biological
knowledge; it is obviously fitting and right that as much
use should be made of it as possible. But we do complain
loudly of the opinion that the application of such know-
ledge is, or should be, the ultimate goal of him who acquires

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An Introduction to a Biology

it. Huxley strongly insisted on the fact that the fruits,
useful to mankind, of the tree of natural knowledge fell un-
sought for and unexpected on the back of the head of some
obscure worker under its shade, and never to him who
worked there with outstretched palm. Dr. Reid says,
p. 331:

“Hitherto the nature of their training has tended to
render medical men excessively conservative. Neverthe-
less, they have already assimilated and put to magnificent
practical use one of the two great scientific achievements
of the age—Pasteur’s discovery of the microbic origin of
disease. The other great achievement, Darwin’s discovery
of the adaptation of species to the environment through
natural selection, has hardly been assimilated, and cer-
tainly put to no practical use as yet. Both these discoveries
should have been made by medical men.”

The fact that they were not is an illustration of the
truth of Huxley’s words.

Let it be emphasised again that we do not hold that
the gradual desertion of biologists from the ranks of the
pure to those of the applied is other than of the greatest
service to mankind. But if this desertion means that the
opinion will grow that the natural goal of the young biologist
is to obtain a position in applied biology, it is a bad thing
for science. The utilitarianism which may lead to the
extinction of the pure biologist is to be deplored. If we are
going to be utilitarians let us at least be good ones, and let
us recognise the demonstrable fact that the only way in
which the knowledge and consequent control of nature can
be acquired is by encouraging the existence of the type of
man who works at his subject for its own sake. Let us have
less of the talk about the profound significance of such and
such a branch of investigation to the sociologist and the
statesman, and more of the frame of mind which finds ex-
pression in Bateson’s words :— ‘‘ We are asked sometimes,
Is this new knowledge any use? That is a question with

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An Introduction to a Biology

which we, here, have fortunately no direct concern. Our
business in life is to find things out, and we do not look
beyond.”

With regard to this utilitarianism, Dr. Reid appears
to us to steer the right course in his book, except perhaps
that he sails rather too near it when, pointing out that a
classical education is inefficient and does not make us like
the Greeks and Romans, he says, “the true modern repre-
sentatives of the great Pagans are not to be found in college
halls or country parsonages, but in thinkers and workers
like Darwin, Huxley, Kelvin, Cecil Rhodes, the strenuous
men who rule Egypt and India. . . .”

Surely the patient inquiring spirit which prompts a man
to devote himself to classics is the same as that in the heart
of the true man of science. One of the greatest steps for-
ward in the study of heredity itself was made by a monk.

[From a lecture delivered at the Graduate School of
Agriculture, Columbia University, Columbia, Missouri, July;
1914.]

. There are two essentially different ways in which
such a subject as Genetics may be presented. One may
either deal with the finished products of investigation ; or
one may fix one’s attention on the machinery of investiga-
tion. These two methods can, of course, never be used abso-
lutely separately ; like all opposite things, each must con-
tain something of the other—matter a little of spirit and
spirit a little of matter, good a little of bad and bad a Little
of good. But the reason that in theory each should contain
the other is that no sane man could be interested in the
products of investigation unless he had previously satisfied
himself that the machinery of investigation, by means of
which those products had been turned out, is sound in con-
struction; and, on the other hand, | think you will agree
with me that the pure philosopher is not the man to over-

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haul this machinery ; you want a man who is himself en-
gaged in the business of investigation. I do not, of course;
go so far as to say that an investigator, to achieve anything,
must be a philosopher as well; nor that a philosopher to
achieve anything at all must be an investigator as well ;
but that the best investigator is he who has a dash of the
philosopher in him, and the best philosopher is he who has
a dash of the investigator in him.

[From an unpublished paper, “The Art of Breeding,”
February, 1911.]

Those who take part in discussions as to the most ait
able way of spending public money on the improvement of
farm live stock may, in nearly all cases, be placed in one of
two perfectly distinct categories, namely the scientific and
the practical.

The Practical Man believes that the success of such
schemes is assured if the planning and the carrying out of
the breeding experiments are in the hands of one who has
devoted his life to the breeding of live stock. The Man cf
Science, on the other hand, believes that we have little
more to learn from the Practical Man, and that the greatest
hope of further improvement lies in the application of scien-
tific methods to the problems of practical breeding.

I believe that neither of these views contains the whole
truth; that both of them contain part of it; but that the
sum of truth made up by the two falls very far short of the
whole truth about the matter. I have intended to suggest
in the title of this paper the direction in which the residue
is to be sought. .

It has not been my lot, though it always has been, and
still is, my wish to follow the profession of a farmer. [
cannot therefore deal with breeding from the standpoint
of one who earns his bread by it. My study of breeding has
been from the purely scientific standpoint ; and I propose

“a

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first to offer some general observations on the relation
between Science and Agriculture.

The Science of Biology has, in this department of it,
the department of genetics, come into very close contact
with the science of agriculture. If you are a pure biologist,
you will say that Biology has stooped down from her
pedestal to hold a lamp for poor little parvenu Agricultural
Science groping in the darkness below, to show her what
the laws of heredity really are. If you are a pure agricul-
turist, you will admit that Biology at last seems to be
beginning to justify her existence in so far as she seems to
be finding out something about the breeding of animals and
plants, which may possibly help the agriculturist to improve
his stock and his corn. The purely academic biologist is
apt to shudder at the thought that his pure and cloistered
science should be degraded by being applied to useful ends.
On the other hand, the rule-of-thumb breeder is apt to
smile contemptuously when he is told that a mere theoriser,
a student of biology, can tell him anything that he doesn’ t
know about breeding. .

You will have gathered from what I have said about
the pure biologist and the pure agriculturist that I am not
going to bestow upon either of them the blessing which
is the expected reward of the pure. We have no use for
either of them. There is no question of biology stooping to
assist agriculture, or of agriculture condescending to make
use of what biology can tell it. There is no question of
one being higher and the other lower. They are side by
side. But they are very different. Agriculture is practical :
when the agriculturist investigates a problem of heredity
he does so solely with a view of improving his stock. Biology
is disinterested: when the biologist investigates a problem
of heredity he does so merely because the problem interests
him and because he wants to find out what is going on.

. It is Just because the two are so different that they
can be so useful to one another. The man whose contribu-

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An Introduction to a Biology

tions to the study of heredity would be most valuable would
be a man who combined the experience of the practical
breeder with the knowledge of the scientific student of
heredity. There are few—I had almost said no such men.

[From a Letter of Application for the post of Director
of Experiments in Animal Breeding, . . . February 11th,
1915.]

I do not think that successful breeding is merely a matter
of the correct application to practice of a true theory of
heredity. Indeed, it is manifestly not so. Successful
breeding—or rather, I should say, the most successful breed-
ing that we know, for a much more highly successful breed-
ing is easily conceivable—successful breeding, I say, is the
work and self-expression of the individual man, individual
enough to conceive an ideal to breed to, and possessing
at the same time an intimate knowledge of what is
wanted in the breed he is interested in. Breeding, accord-
ing to my belief, is an art. The relation between the science
of heredity and the art of breeding is an extremely import-
ant question, both to the student of heredity and to the
practical breeder, and I think it is desirable that I should
state what my attitude towards this question is,

I was in Aberdeen a month ago, reading a paper on an
aspect of heredity to a combined meeting of the Scientific
and Agricultural Societies at the University, and on the fol-
lowing day I went with a large party of old students to see
Mr. Findlay’s herd of Aberdeen-Angus cattle at Aberlour,
At the luncheon, a speaker quoted a remark of Mr. Duthie’s
which Mr. Duthie had made on the occasion of a similar
visit to his Shorthorns. This remark was quoted by the
speaker and delivered by him with a friendly mock emphasis;
as a golden rule which was offered by Mr. Duthie to an
audience expectant of useful hints as to the breeding of
Shorthorns; “If you are a good man you will breed good

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An Introduction to a Biology

cattle.” Everybody, including myself, laughed at it as a
genial pleasantry ; but since then, I have come to see that
it is one of the most pregnant utterances on the subject of
breeding that I have heard. It embodies in an epigram-
matic way all that is meant by the statement that breed-
ing is an art. It means that it requires a man of force and
personality, like Bakewell, for instance, to foresee an ideal
and attain to it by methods of which he himself, like the
musician, is probably unconscious. It requires an inborn
gift to force a new breed, or an improvement of an old
one, on the acceptance of mankind, just as it requires an
inborn gift to express oneself by means of an arrangement
of sounds which mankind will recognise as music. What
then is the relation of science to this art of breeding? The
answer, in my opinion, is that it is the business of science
(to change the simile) to supply the best pigments and
brushes wherewith the picture is to be painted; to place at
the disposal of the breeder the instruments of precision
which will enable him to carry out his work efficiently. The
breeder knows, pretty well, the end he wishes to attain ;
it is the function of science to supply him with the means
which shall enable him most expeditiously to reach that
end.

126

I]

On the Bearing of Mendelian Principles of
Heredity on Current Theories of the
Origin of Species

(Manchester Memoirs, Vol. alviir., 1904, No. 24)

A wIbE field of work and speculation has been opened up
to the student of evolution by Mendel; and by his fol-
lowers it has been maintained that it is only by working
on the lines laid down by the Abbot of Briinn that a solu-
tion of the problem of the origin of species can ultimately
be reached. It is the object of this paper to show the rela
tion which Mendel’s work bears to current theories of organic
evolution.

(1) ON THE DIFFERENCE BETWEEN CONTINUOUS AND Dis-
CONTINUOUS VARIATION

For an account of continuous variation the reader is
referred to the Presidential Address to Section D of the
British Association, at the Bristol Meeting, by Professor
Weldon (Weldon, ’98)1: discontinuous variation is set forth
by Mr. Bateson in his work “ Materials for the Study of
Variation”? (Bateson, ’99); all that remains for me to do
is to call attention to some of the differences between these
two conceptions of variation.

Continuous variation is the name of a phenomenon of
everyday observation, namely, the fact that no two indi-
viduals of a species (plant or animal) are alike; it is a
permanent quality of all animals and plants at all times,
tending, as far as we can see, in any direction (and as little

1 Vide List of Authorities, p. 139 infra.
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An Introduction to a Biology

teleological in any sense of the word as anything can be
imagined to be). Above all, cases of continuous variation
can be described by curves of error, a fact which seems to
me to have a very deep meaning. Discontinuous variation
is the quality which animals and plants possess of giving
rise, from time to time, to offspring bearing characters
specifically different from those of their parents: in fact,
by some these offspring are termed “ sports.” This “ sport”
is a new species: that is to say (to use Bateson’s words),
“Variation, in fact, 7s evolution” (’99, p. 6); but while
this can be said of discontinuous, continuous variation is
merely the material upon which natural selection operates
(if we may thus personify that process). From this it follows
that according to the latter view it is impossible to say
where one species begins and the other ends; but that
according to the former view there is no such difficulty.

‘Continuous variation may be looked upon as normal,
while discontinuous may be regarded as abnormal; but
this aspect of the matter is perhaps only justifiable as a
help to understanding the difference. For if species have
arisen by discontinuous variation it is hardly fair to call
it abnormal. (Vide Ewart, ’99, p. Ixxxiv.)

The word “ Variation”? may represent an abstract or a
concrete thing: in the continuous sense it is usually a name
given to the whole phenomenon of variation: in the dis-
continuous, the so-called sport is often spoken of as “a
variation” (whereas a man with a cephalic index slightly
less than his neighbour’s would hardly be). This twofold
use of the term conveniently recalls the two conceptions of
variation.

(2) GaLton’s THEORY OF HEREDITY

I refer to Galton’s theory of heredity because I want to
show how the Mendelian theory differs from the statistical
conception of that phenomenon. Galton said: ‘ The two
parents contribute between them on the average one-half,

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An Introduction to a Biology

or (0°5) of the total heritage of the offspring; the four
grandparents, one quarter, or (0°5)?; the eight great-
grandparents, one eighth, or (0-5), and so on. Thus the
sum of the ancestral contributions 1s expressed by the
series {(0°5) + (0:5)? + (0°5)3, &c.}, which, being equal to 1,
accounts for the whole heritage.” (Galton, °97, p. 402.)

(3) Menpew’s INVESTIGATIONS

Mendel, an account of whose life and a translation of
whose work has been given by Bateson (:02a), conducted
hybridisation experiments with peas in the cloister garden
of the monastery at Briinn of which he was Abbot. He
had found that peas differed from one another in respect of
seven characters, only one of which, for the sake of sim-
plicity, I propose to consider; that is, the colour of the
seed: this was either yellow or green. When he crossed a
green-seeded pea with a yellow-seeded pea, the hybrid which
he obtained was always the same with regard to that char-
acter; it was always a yellow-seeded pea. Yellow-seeded-
ness therefore was called a dominant character; and green-
ness of seed a recesswve character. When the hybrids were
allowed to breed (they were self-fertilised), a curious result
was obtained: 25% of the offspring were green-seeded and
75% yellow-seeded. Now it will be remembered that the
hybrid was yellow-seeded; and also that that was the
character of one of the parents of the hybrid; so that by
mere inspection of the yellow-seededness of this 75%, we
cannot tell whether they are all pure yellows, or all hybrids,
or some pure yellows and some hybrids. But we can tell
this by breeding from these yellow-seeded peas; for it is
known that pure yellows breed true, and we have just seen
that hybrids produce 25% green-seeded and 75% yellow-
seeded peas. Suppose we take actually 75 yellow-seeded
peas (the number, of course, does not matter, so long as it
is large; but 75 is convenient, as we shall shortly see), and
plant some seeds from each plant. What Mendel found

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An Introduction to a Biology

was this: 50 of the 75 were hybrids because 25% of their
offspring were “ green”? and 75% “ yellow” (which we will
now write instead of “ green-seeded ” and “ yellow-seeded ”),
while the remaining 25 proved themselves to be pure yellows
by breeding true—by producing only “yellows.” That is
to say, the 75 yellow peas are composed of 50 hybrids and
25 dominants; and now that we have at last found out
what they are, let us look at the whole result of breeding
from the hybrids. We see immediately that :—
25% greens + 75% yellows
is really represented by

25% pure greens 50% hybrid yellows 25% pure yellows

or
25% recessives 50% hybrids 259, dominants.

Mendel experimented with the new hybrids (i.e. the
children of the first hybrids) and found that they, too, pro-
duced offspring, 25° of which were green and 75% yellow ;
and he found (though he was working with small numbers:
Bateson, :02, p. 57) that, for at most six generations, it was
a general rule that hybrids when paired together gave 25%
recessives, 50°% hybrids, and 259% dominants. This pheno-
menon is spoken of as segregation ; which consists in the
dispatch by the hybrids, at each generation, of offspring into
the dominant and recessive ranks from which (so long as like
mates with like) there is no returning.

If we symbolise the dominant character by D, the reces-
sive by R, and the hybrid by DR (and if we imagine for the
sake of simplicity that each plant produces 4 seeds), we
see that the proportions of D’s, DR’s, and R’s in successive
generations are as shown in the table on the following page.
The ratio of D’s, DR’s, and R’s can be foretold in any
generation , by this formula:

Ds DEA i
idl Seen” Bal
“In the tenth generation, for instance, 2”— 1 = 1,023.
There result, therefore, in each 2,048 plants which arise in
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An Introduction to a Biology

Ratios.
Generation. D. DR. rt De DR URS
L 1 2 1 PAw<9 1
(Ab a 2 4)
- 6 4 6 A 3
vyNn
Se ae SS ea
3, 28 8 28 Leia a aela a
xeYNS
Th ie is Cais ie he
4, 120 16 120 1 a pe 15
“yrs
(480+16 32 16 + 480)=
5. 496 32 496 31 yas 4

this generation 1,023 with constant dominant character,
1,023 with the recessive character, and only two hybrids”
(Bateson, ’02, p. 59).

(4) Menpet’s THEory To AccoUNT FOR HIs RESULTS

Mendel knew that green-seeded peas bred true, when
self-fertilised or cross-fertilised by other green peas; and
that the same was true of the yellow. That is to say, the
germ-cells of green peas will always produce green peas,
and those of yellow will continue to give yellow.

But what happens when a green pea is crossed with
a yellow: that is, when a “green” germ-cell meets a
“yellow” germ-cell? We know that a_ yellow-seeded
hybrid is produced ; but we want to know the condition of
its germ-cells. Mendel’s hypothesis was that it contained
50% “ yellow ” germ-cells and 50% “ green” ; no “ greenish-
yellow” and no “ yellowish-green”’ germ-cells, but equal

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An Introduction to a Biology

numbers of green-producing and yellow-producing gametes ;
he maintained that no fusion of characters (like a chemical
combination) takes place, but merely a mingling (like a
mechanical mixture).

The proportions in which the D’s, DR’s, and f’s occur
in the offspring of hybrids is certainly accounted for by this
theory. Let us (putting aside sex for brevity’s sake) imagine
what happens when a hybrid is cross- or self-fertilised.
Imagine, first, a “green” germ-cell: it is an even chance
that it unites with a “ green” or “ yellow.”

a.GxG@

RL a oe
Imagine a “ yellow”: it has an even chance of uniting with
a “green” or “ yellow.”

ae Soa

Ae ae

Now b and ¢ are the same; so that the proportions in
which pure “ greens,” pure “ yellows,” and hybrids would be
produced, as the result of the random unions of the germ-
cells of two hybrids, would be 1@ : 2GY (hybrid): 1Y, in
every four; or, of course, 25% D: 50% DE: 25% R. And
this is exactly what happens as the result of actual breeding.

(5) A Drvicr ror EXPLAINING MENDEL’s THEORY

I think this theory may be made clearer by a device
which has been useful to me: some have imagined that it
is intended merely as an instance of the application of the
theory of probability: this, however, is not the case; its
value, such as it is, lies in the way the process is managed,
which has nothing to do with probability.

All that is needed is some red and white counters.

Mendel’s conception of the gonad of a hybrid as an organ
containing germ-cells, 50% of which bear the dominant
character and 50% the recessive, can be easily imitated
by a bag containing equal numbers of red and white counters :
in fact, the production of the hybrid (or rather its gonad)

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An Introduction to a Biology

may be imitated by pouring equal numbers of red and white
counters into some convenient receptacle. Now let us pair
two such imitation hybrids, using for this purpose two bags
or hats, each containing equal numbers of red and white
counters. Two vertical lines are drawn on a large sheet of
paper ; the space between the lines being reserved for pairs,
each consisting of a red and a white (RW); the space on
one side of the two lines for two reds (RR), and that on the
other for two whites (WW). A counter is taken at random
out of one hat; then another out of the other hat; and the
pair, according to its character (RR, RW or WW), is assigned
to the column, on the paper, prepared for it. We should,
of course, expect in a large number of trials that there would
be 25% RR, 50% RW, and 25% WW; this is, in fact, what
happens. Now in playing this game there is only one rule
to be observed, which is, “ When a red is drawn with a white
the red shall be placed on the top of the white.” (It is this
rule that confers whatever usefulness there is in this device.)
Let us make fifty draws and place the result on the paper:
the outcome of such a trial taken as I write is 13 RR, 26
RW, and 11 WW; which, for the smallness of the number
drawn, is not a bad approximation. Let that colour repre-
sent the dominant character, which was placed uppermost
in the RW’s; let W be the recessive and RW the hybrid:
the observance of the only rule of the game brings out the
fact that in the hybrid it is the dominant character which
is manifested, while the recessive is hidden. Now, in placing
the RW’s on the paper one is not likely to absolutely con-
ceal the white; so that, while from our rule we realise that
red is the character which the hybrid bears, we are pre-
vented (by the fact that the white is not absolutely con-
cealed) from forgetting the real constitution of the hybrids
(or rather their gonads), namely, that they contain germs
representing respectively dominant and recessive characters
in equal numbers. It will be seen from this illustration
that, in making the living cross, all that is done is to mingle
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An Introduction to a Biology

(if this word may be used of two objects) the germ-cells
together 1 like counters in a hat; and that, in the resultant
hybrid, the germ-cells differ from the two which took part
in its formation, only in actual number; for the propor-
tions are the same (50% dominant and 50% recessive) and
the discontinuous condition of the germ-cells is the same,
inasmuch as a germ-cell represents either a dominant or a
recessive, and never partly one and partly the other; in
fact, it is no more possible to produce such an intermediate
stage than it is possible to get a pink counter by shaking
up scarlet and white ones in a hat. To look for a moment
at the offspring of the hybrids: Mendel says that the “ ex-
tracted” dominants (the dominant offspring of the hybrids)
will always breed true; and that the same is true of the
“extracted” recessives: this can be illustrated in our
imitation hybridisation experiment by placing half the RA’s
in one hat and half in another; it is evident that nothing
but reds can be got from “ matings ”’ from these two hats.

It is also a fundamental part of the Mendelian principle
(in fact, 1t seems to me to be its foundation-stone) that
the “extracted” hybrids will produce the same kind, and
proportions of the three kinds, of offspring as the first
hybrid ; for if half the RW’s are put into one hat and half
into another it is evident that random matings will give
25% RR, 50% RW, and 25% WW as before, and, what is
more, that they will continue to do so (so long as we keep
up the number of counters) for however long we continue
the process, that is to say, for howsoever many generations
it is carried on.

(6) A Potnt oF DIrFERENCE BETWEEN GALTON’S AND
MENDEL’s THEORY

I do not propose to discuss here the difference between
the Mendelian principles and the statistical conception of

1 Of course the germ-cells fuse: it is the character-bearing elements
which are thus mingled.

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An Introduction to a Biology

inheritance, but to consider one part of the hypothesis put
forward by Mendel, which is at variance with Galton’s
theory. I refer to the phenomenon of segregation. We
have seen what Mendel says (see Bateson, :02, p. 57).
But this is flatly contradicted by the Galtonian generalisa-
tion, according to which the greater number of generations
a given hybrid is from the first hybrid (i.e., of course, also
from the parents of the hybrids), the fewer pure reces-
sive and dominant forms is it likely to produce when mated
with another hybrid of its own generation (Darbishire, :04,
pp- 23 et seq.).

I refer to this point (which at first sight may appear
insignificant, but in reality is not) because it seems to me
to afford a means of deciding between the relative validity
of the two theories, inasmuch as it is a matter about which
the Mendelian and Galtonian predictions are totally at
variance ; and because I think the time has not yet come for
such statements, as, for example, this from the pen of Pro-
fessor Castle (:03a, p. 228): “It” (Mendel’s theory) “ thus
meets the two-fold requirement of a scientific theory, a
statement of phenomena and an explanation of them; the
‘law of ancestral heredity’ attempts only the first of these
two things, and even here fails lamentably. It will be thus
seen that the claims of Mendel’s law are much greater than
those of Galton’s law.” The italics are mine (see Karl Pear-
son, ‘Grammar of Science,” p. 121; and also, in this con-
nection, Pearson, :04).

(7) New CoNcEPTIONS BASED ON MENDEL’s INVESTIGATIONS

I will only refer to three of these: the curious reader is
referred to Bateson’s “‘ Mendel’s Principles of Heredity,”
p. 26.

(a) The first of them is “the purity of the gametes in
regard to certain characters” (Bateson, :02, p. 26). This
generalisation is based on the often repeated fact, that (to
take an example) in respect of the colour of the seed a

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An Introduction to a Biology

germ-cell of a pea, whether it be contained by the pure
yellow or pure green race, or by the hybrid or any of its
descendants, ts absolutely pure. And it is believed that it
will continue to be pure in respect of these characters until
a specific upheaval takes place, when a new character will
arise by the process of discontinuous variation.

(6) The second is the conception of wnit-characters (l.c.,
pp. 27-28) in respect of which the gamete is pure. Such
units seem to correspond to that in the adult organism which
Weismann sought in the germ. These unit-characters, as
we have seen, usually exist in pairs in such a way that one
is dominant and the other recessive; and this fact is recog-
nised by naming such characters allelomorphs. It is hardly
necessary to say that the germ contains not merely one allelo-
morph (as we have been imagining for the sake of simplicity),
but very many; in fact, Mendel recognised seven such pairs
in his peas, and this must be the merest fraction of the
actual number that exists.

(c) We are thus indirectly led to the conception of ‘‘ com-
pound characters, borne by one gamete, transmitted entire as
a single character so long as fertilisation only occurs between
like gametes” (l.c., p. 29). The reader is here strongly
advised to refer to the first thirty-five pages of Bateson’s
book (Bateson, :02a).

(8) THe RELATION BETWEEN THESE NEW CONCEPTIONS AND
THE THEORY OF THE ORIGIN OF SPECIES BY DIScON-
TINUOUS VARIATION (a, GAMETIC PuRITY; b, UNIT-
CHARACTERS ; c, COMPOUND CHARACTERS).

Let us suppose a new character to arise by discontinuous
variation ; for example, the possession of a trunk in a race
of previously snoutless elephants. According to the statis-
tical view of heredity this new character would be soon
swamped by the, so to speak, normal trunkless ancestry of the
new form itself and of its mate; for one of two courses is
open to the new form: it may either unite with another like

1360

‘.

An Introduction to a Biology

it, which would depend on a series of contingencies — the
production of two such beasts at the same time, at the same
place, of opposite sexes, and the condition that they were not
averse to one another; or it might unite with a trunkless
relative. But even in the former case the offspring would have
a smaller trunk than its two parents. And if this smaller trunk
were to be perpetuated its owner would have to unite with
another trunk-bearing variety, which therefore would have
to arise at the proper time, be of the opposite sex, and in
the neighbourhood ; but even if the smaller trunk were lucky
enough to find such a one its offspring would be less trunked
even than itself! If the original trunked variety paired
with a trunkless relative the swamping would be ever so
much faster. But I leave the reader to pursue this argu-
mentation for himself—suffice it to say that these trunk-
bearing sports would on this. view be very soon wiped out.

But if we adopt the conceptions of gametic purty and
unit-characters, there is no reason, when once the varia-
tion has arisen, why it should not be perpetuated. For
its germ-cells represent trunk-bearing elephants; if it mated
with a similar beast its offspring would all be trunk-bearing
and in the same degree; if, on the other hand, it met a
trunkless form, the result of such a union—the hybrid, in
other words—would have a trunk if the possession of that
organ were dominant, and would not if it were recessive ;
but whichever of these was the case, 25°% of the next genera-
tion would be true-breeding trunk-bearers; and so on.
This illustration may be crude, but I hope it shows the kind
of way in which, according to these new conceptions, such
a variation might be perpetuated; while according to the
biometric view of heredity this would not be the case.

We have seen that a single unit-character continues to
produce its like so long as it unites with its like until a new
variation arises from it; but, when we come to consider
(c) Compound characters, we find that new characters can
arise in another way than by a discontinuous variation.

137

An Introduction to a Biology

I will take an example with which I am familiar. When a
yellow-and-white Japanese waltzing mouse is crossed with
an albino, a hybrid is produced which is unlike either parent,
being, with some exceptions, hardly distinguishable from
the common house-mouse (see Bateson, :02, note on p. 55 and
pp. 24 and 25). This hybrid (I have bred some 350) is never
an albino, and it never waltzes: albinism and waltzing there-
fore are recessive characters; and pigmentation and normal
progression are the corresponding dominant characters. So
that we are crossing a creature—the albino—possessing
normality of progression (D) and albinism (#) with another
beast which exhibits waltzing movements (£) and the pre-
sence of pigment (DP). Let us consider the offspring of
hybrids thus produced from the point of view of the two
pairs of allelomorphs. First, with regard to colour, we
should expect 25° albinos which should breed true: this is
in fact what we get. Secondly, with regard to their pro-
sression, we should expect to find 25°% waltzing mice: this
is very roughly what happens. I have been unable to deter-
mine if they breed true (on the Mendelian hypothesis they
should, of course). Now let us look at the offspring of
hybrids from both points of view at the same time: one
mouse in every four is an albino; one in every four is a
waltzer, so we should expect one in every sixteen to be an
albino waltzer. Now these albino waltzers are new things ;
and, what is more, they should breed true, because both
their characters (A and W) are recessive. What has hap-
pened is that we have taken the recessive character—albinism
—from one parent of the hybrid, and the recessive char-
acter—‘* waltzing”’—from the other; and through the
mediation of the hybrid united them in one individual—
the new albino waltzer—which will produce nothing but
ofispring like itself, because its gametes are pure.! I have

17 am not sure that this case is not, strictly speaking, an example of a
synthetical variation ; at any rate, it is a very simple instance of the argu-
ment set forth in Bateson, :02a, p. 29.

138

An Introduction to a Biology

bred several examples of this new species, but have so far
been unable to obtain young from them.

The reader may suspect that there is something pecu-
liar about these two characters—albinism and waltzing—
that the former is one that 1s likely to have arisen as a sport,
and that the latter is, in a way, pathological, and that both
are of such a kind as to be very quickly eliminated in the
struggle for existence: my opinion is that such a suspicion
is of great interest. But I do not propose to discuss the
source of such variations here: all I have tried to do is to
sketch the relation which exists between Mendelian Prin-
ciples and current theories of the origin of species.

LIST OF AUTHORITIES REFERRED TO IN
THE TEXT ;

Together with most of the literature on the subject
which has appeared during and since 1902.

°65. MENDEL, GREGOR. Versuche iiber Pflanzen-Hybriden.
Verhandl. d. Naturforsch. Ver. Briinn, Vol. 4, 1865
(Abhandlungen).

"94. Bateson, W. Materials for the Study of Variation.
Macmillan, London.

96. PickertInc, J. W. Coagulation in Albinos. Journ.
Physiol., Vol. 20, p. 310.

"97. GaLToN, Francis. The average Contribution of each
several Ancestor to the total Heritage of the Off-
spring. Proc. Roy. Soc., Vol. 61, pp. 401-13.

°98. WxeLpon, W. F. R. Presidential Address to Section D,
British Assoc., Bristol. B. A. Report, 1898.

°99. Ewart, J. Cossar. The Penycuik Experiments. A. and
C. Black, London.

700. Davenport, C. B. Review of von Guaita’s experi-
ments in Breeding Mice. Brol. Bulletin, Vol. 2,
pp. 121-8.

:00. Pearson, Kart. The Grammar of Science. A. and C.
Black, London.

:01. Correns, C. Die Ergebnisse der neuesten Bastard-

<9)

An Introduction to a Biology

forschungen fiir die Vererbungslehre. Ber. deutsch.
bot. Gesellsch., Vol. 19, generalversammlungs Heft, pp.
72-94.

:01. Zora, O. Ein Beitrag zu der Beobachtungen und
Versuchen an japanischen Tanzmaiisen. Arch, f. d.
gesamm. Physiol., Vol. 86, p. 147.

:02a. Bateson, W. Mendel’s Principles of Heredity: a
Defence. Cambridge.

:02b. Bateson, W. Note on the Resolution of Compound
Characters by Cross-breeding. Proc. Camb. Phil.
Soc., Vol. 12, Part 1, pp. 50-4.

:02. Bateson, W., and Saunpers, EH. R. Experimental
Studies in the Physiology of Heredity. Reports to the
Evolution Committee of the Royal Society. Report L,
London, 1902.

:02. Cufnor, L. La Loi de Mendel et ’Hérédité de la Pig-
mentation chez les Souris. Arch. Zool. exp. et gén.,
Vol. 27, 1902.

:02. Doncaster, L. On Rearing the later Stages of Echinoid
Larve. Proc. Camb. Phil. Soc., Vol. 12, Part 1, pp.
47-9.

:02. Hurst, C. C. Mendel’s Principles applied to Orchid
Hybrids. Journ. Roy. Hortic. Soc., Vol. 27, Parts 2
and 3; pp. 614-24.

:02. Pearson, Karu. On the Fundamental Conceptions of
Biology. Biometrika, Vol. 1, pp. 320-44.

:02a. SprntMaNn, W. J. Quantitative Studies on the Trans-
mission of Parental Characters to Hybrid Offspring.
Bull. 115. Office of Exp. Sta. US. Dept. Agric.,
pp. 88-98.

:02b. Spinpman, W. J. Exceptions to Mendel’s Law.
Science. N.S., Vol. 16, pp. 794-6.

:02a. TscHERMAK, E. Ueber die gesetzmassige Gestaltungs-
weise der Mischlinge (Fortgesetzte Studie an Erbsen
und Bohnen) Zeztschr. f. landurrths. Versuchswesen in
Oester. Jahrg. 5.

:02b. TscHERMAK, E. Der gegenwartige Stand der Men-
del’schen Lehre und die Arbeiten von W. Bateson.
Ibid. Jahr. 3, 1902.

:02a. WELDON, W. F. R. Professor de Vries on the Origin of
Species. Biometrika, Vol. 1, pp. 365-74.

140

An Introduction to a Biology

:02b. Wetpon, W. F. R. On the Ambiguity of Mendel’s
Categories. Biometrika, Vol. 2, p. 44.

:02. Witson, E. B. Mendel’s Principles of Heredity and the
Maturation of the Germ Cells. Sczence, N.S., Vol.
16, No. 416, p. 991.

02. Yuute, G. U. Mendel’s Laws and their Probable Rela-
tions to Intra-racial Heredity. The New Phytologist,
Vol. 1, pp. 193-207 and pp. 222-37.

:03a. Barzson, W. The Present State of Knowledge of
Colour-Heredity in Mice and Rats. Proc. Zool. Soc.,
Wit: ee PRS

:03b. Bateson, W. Mendel’s Principles of Heredity in Mice.
Nature, 67, pp. 462, 585; 68, p. 33.

703. CasTLE, W. E., and ALLEN, G. M. The Heredity of
Albinism. Proc. Amer. Acad. Arts and Sci., Vol. 38,
No. 21.

:03a. CastLE, W. E. The Laws of Heredity of Galton and
Mendel, and some Laws governing Race Improve-
ment by Selection. Jbid., Vol. 39, No. 8.

703. CasTLE, W. E., and Faraser, W. C. Notes on Negro
Albinism. Scvence, Vol. 17, p. 75.

:03b. CastLE, W. E. Mendel’s Law of Heredity. Science.
N.S., Vol. 18, No. 456, pp. 396-406.

:03. Correns, C. Ueber Bastardirungsversuche mit Mira-
bilis-Sippen. Erste Mittheilung. Ber. deutsch. bot.
Gesellsch., Vol. 20, pp. 594-608.

:03a. CuENoT, L. La Loi de Mendel et l'Hérédité de la Pig-
mentation chez les Souris. Compt. Rend., Paris,
Vol. 134, pp. 779-81.

:03b. CuENoT, L. LHérédité de la Pigmentation chez les
Souris (2" Note). Arch. Zool. exp. et gén., Vol. 1,
Notes et Revue, No. 3, pp. 33-41.

03. Denpy, ArtHuR. The Nature of Heredity. Rep. of the
S. Afr. Ass. for the Adv. of Sct., Vol. 1, pp. 317-40.
April, 1903.

:03. Doncaster, L. Experiments on Hybridisation, with
special reference to the Effect of Conditions on
Dominance. Proc. Roy. Soc., Vol. 71, p. 497.

:038. Doncaster, L. Experiments in Hybridisation, with
special reference to the Effect of Conditions on
Dominance. Phil. Trans., B., Vol. 196, pp. 119-73.

141

:03.

:03.

:03.
:03.

:03.

:03.

03.

:03.

“03,

:03.

:03.

ath a
:03.

:03.
:03.
Riedel

304.

:O4.

An Introduction to a Biology

Garrop, A. Ueber Chemische Individualitét und
Chemische Missbildungen. Pfliiger’s Arch. f. d.
gesamm. Physiol., Vol. 97.

GiarD, A. Caractéres Dominants Transitoires chez
certains Hybrides. Compt. rend. des Séances de la
Soc. de Biologie, Vol. 55, p. 410.

Giarp, A. Les faux Hybrides de Millardet et leur inter-
prétation. Ibid., Vol. 55, p. 779.

Grecory, R. P. The Seed Characters of Pisum Sativum.
New Phytologist, 1903, December, p. 226.

Hickson, 8. J. Presidential Address to Section D,
British Association, Southport, 1903. B. A. Report,
1903.

Hurst, C. C. Mendel’s Principles applied to Wheat
Hybrids. Journ. Roy. Hortic. Soc., Vol. 27, Part 4,
pp. 876-93.

Morean, T. H. Evolution and Adaptation. The Mac-
millan Company, New York.

Noorpuyn, C. L. W. Iets over Kleuren, Kleurverander-
ing der Vogels en paring van variéteiten. Album der
Natuur. December, 1903.

Pearson, Karu. The Law of Ancestral Heredity. Bio-
metrika, Vol. 2, p. 211.

Punnett, R. C. Note on the Proportion of the Sexes
in Carcinus maenas. Proc. Camb. Phil. Soc., Vol. 12,
Part 4, pp. 293-6.

Vernon, H. M. Variation in Animals and Plants.
(Internat. Sci. Series.)

Vrizs, Huco pg. Die Mutationstheorie. Vol. 2. Leipzig.

Vries, Huco pe. Befruchtung und Bastardierung.
Von Veit, Leipzig.

Wepon, W.F.R. Mr. Bateson’s Revisions of Mendel’s
Theory of Heredity. Biometrika, Vol. 2, p. 286.
Wetpon, W. F. R. Mendel’s Principles of Heredity in

Mice. Nature, 67, pp. 512, 610; 68, p. 34.

Voops, F. A. Mendel’s Laws and some records in
Rabbit Breeding. Biometrika, Vol. 2, p. 299.

Cuznot, L. L’Hérédité de la Pigmentation chez les
Souris. (3"° Note.) Arch. de Zool., exp. et gén., 1904
(4). Vol. 2, Notes et Revue, No, 3, pp. 45-56.

Dareisuire, A. D. On the Result of Crossing Japanese

142

:04.

704.

704.

704.

704.

704.

704,

704.

An Introduction to a Biology

Waltzing with Albino Mice. Biometrika, Vol. 3,
Part 1, p. 1.

Davenport, C. B. Colour Inheritance in Mice. Science.
N.S., Vol. 19, No. 472, pp. 110-14.

Davenport, C. B. Wonder Horses and Mendelism.
Science. N.S., Vol. 19, No. 473, pp. 151-3.

Hurst, C. C. Experiments in the Heredity of Peas.
Journ. Roy. Hort. Soc., Vol. 28, Parts 3 and 4, p. 483.

Prearson, Karu. Mathematical Contributions to the
Theory of Evolution, XII.—‘‘On a Generalised
Theory of Alternative Inheritance, with special refer-
ence to Mendel’s Laws.” Proc. Roy. Soc., Vol. 72,
pp. 505-9.

PraRsON, Karu. Same title. Phil. Trans. Roy. Soc.,
Ser. A., Vol. 203, pp. 53-86.

PEarRson, Karu. A Mendelian’s View of the Law of
Ancestral Inheritance. Biometrika, Vol. 3, Part 1,
p- 109.

TscHERMAK, E. Die Theorie der Kryptomerie und des
Kryptohybridismus. Bethefte zum Botanischen Central-
blatt (Original Arbeiten). Vol. 16, Part 1, pp. 11-35.

We tpon, W. F. R. Albinism in Sicily and Mendel’s
Laws. Biometrika, Vol. 3, Part 1, p. 107.

Ill

On the Supposed Antagonism of Mendelian
to Biomeiric Theories of Heredity

(Manchester Memoirs, Vol. alix., 1905, No. 6)
ie

DISSENSIONS in scientific matters may be said to be of two
kinds, of which one is a disagreement about fact and can
be settled by an appeal to fact, while the other is the con-
flict of theoretical interpretations which cannot be so easily
concluded. When Owen said that an ape’s brain had not
a hippocampus minor and Huxley asserted that it had,
Flower announced that he had an ape’s brain in his pocket ;
and the dissection of the brain put an end to the discussion.
But in the second form of controversy no such touchstone
can be applied, and in the debate on heredity at Cambridge
this year Mendelian maize-cobs were displayed in vain. Of
this kind of controversy there are again two sorts, one in
which the theories put forward by the opposite factions
are mutually exclusive, and another in which, while there
is apparent incompatibility, the truth of both of the hypo-
theses is ultimately demonstrable. It remains to be seen
to which of these subdivisions the Cambridge debate,? and
the wider discussion of which it was the outcome, are to
be assigned. If the two theories are mutually exclusive,
which is right? If, on the other hand, they are not, how

1This essay is so arranged that if the reader is not interested in the
phenomenon of hybridisation he may leave out Part 2.
2 Reported in Nature, Vol. 70, pp. 538-9.

144

+ :
An Introduction to a Biology

do they fit in with one another? These are questions which
“the general inquiring public” may be expected to ask
and to which the specially trained biologist may be expected
to supply an answer.

It is the thesis of the present essay to demonstrate the
compatibility of Mendelian and biometric theory and to
account for their apparent antagonism.

A few words as to the spirit and scope of this essay seem
to me to be necessary. There are two methods of scientific
criticism, if, indeed, one of them can be justly called scientific,
One arises from a determination to crush a theory, while
the other consists in the postponement of the attack until
every endeavour has been made to appreciate the exact
point of view of the upholders of that theory, and in a willing-
ness to put off the attack for ever if the theory should not
be found wanting after all. The most flagrant example of
the first kind of criticism, on which I can lay hands, flowed
from the pen of a writer who, after having misrepresented
the theory he was attacking by declaring that it was “an
essential part of the Mendelian hypothesis that the (so-called
“extracted ’’) recessive individual which is produced by
pairing two first crosses is in every respect similar to the
original pure recessive,” 1 concludes with these words: “ This
mouse is clearly not a pure dominant, because it produces
albinos ; it is not a dominant hybrid, because it has pink
eyes ; and it cannot be a recessive, because when paired with
an albino it produces some black-eyed forms.” It is evident
from this quotation that the stimulus which actuated the
author was a desire to stultify and refute Mendelian theory
at all costs, and that he did not make the smallest attempt
to discover what Mendelian theory really was or to put
himself in the position of those who held it to be true. For
an example of the second form of criticism I suggest that
the reader may turn to the followimg pages; in them I
shall do my best to discover the most essential character-

1A, D. Darbishire, Biometrika, Vol. 2, pp. 282-5.

K 145

An Introduction to a Biology

istics of Mendelian and biometric theory and so to put myself
in a position to discuss their mutual relationship. |

With regard to the scope of this essay, there is one point
I wish to emphasise: it may be that some critic will lay
down this pamphlet with the remark that all that he has
read may be very true, but that the fact remains that the
only thing which “ matters”’ is the mass-phenomenon; or
another may declare that the key which will unlock the
secret of heredity can only be obtained by a study of the

2°

properties of the germ-cells. I do not propose to express

an opinion on either of these contentions, but I wish most
strongly to insist that when a man has made either of them,
he has stepped from one country into another. After dis-

cussing the mutual relation of two theories, he suddenly —

asserts that after all it is only one of them that matters—as
one who during a discussion of the evidence for and against
the existence of mental activity after the death of the brain
should declare that after all, belief in such a survival was

a great comfort to many: both questions may be worth —

discussing, but they should be discussed separately. In
this essay I propose to treat of the mutual relations of the
two theories purely as theories, without touching on the
question of their possible value to the pure or applied biologist.

The reader may easily convince himself by a perusal of
the literature on this subject that the self-same facts are
interpreted by the rival schools of thought in the light of
their own theories ; and if he looks for recognition from either
party that there may be something of truth in the opinions
of their opponents, he will search in vain. I do not propose
to discuss the opposite points of view, because I believe
that the remedy for the present inconclusiveness of the dis-
cussion lies very deep, and is to be found in the clear appre-
ciation of the fundamental relation between the biometric
and Mendelian points of view.!

1 The reader who wishes to follow the discussion of the facts at first hand

will find the necessary references to four cases in the Appendix (see p. 161).

146

’ ew

“*

as

An Introduction to a Biology

II

At a time when I did not clearly see this relation, I had
before me some data which convinced me that the Men-
delian interpretation of the phenomenon of segregation was
wrong, and that the facts were striking evidence of the
truth of Galton’s theory.

' There are two attributes of a heterozygote which are
said to follow from the theoretical constitution of its gonad ;
one is that a quarter of the population produced by the
union of heterozygotes consists of individuals bearing the
recessive character, and the other is that half the population
produced by mating heterozygotes with recessives consists
of recessives. My hybrids! were tested for these two pro-
perties and the results were not denied to be in accord with
Mendelian expectation. But this result was not conclusive
in favour of that theory only, because the proportion of
recessives demanded by Mendelian theory in the case of the

_ first property was identical, and in the case of the second

only slightly less than that which follows from the truth
of Galton’s generalisation.”

The Galtonian prediction of the number of albinos that
will be produced by two hybrids (H), each of which is the
ofispring of a pure-bred waltzing and a pure-bred albino
mouse, is -25 of their generation ; while on that theory the
proportion of albinos in a generation resulting from the
union of hybrids with albinos (A) is -53125, if we only calcu-
late as far back as the great-grandparental generation.

We have seen, therefore, that hybrids were mated with
hybrids, and that they were also mated with albinos. In
this way two kinds of hybrids were produced which could
not be distinguished from one another by their outward
appearance, but difiered in the amount of their albino an-
cestry ; for while the one kind, which we may call HH,
resulted from the union of two hybrids, the other, H4,

1 Biometrika, Vol. 3, pp. 30-33.
2 Francis Galton, ‘‘ Proc. Roy. Soc.,”’ Vol. 61, p. 402, line 13.

147

An Introduction to a Biology

was the ofispring of a hybrid and an albino. I took those
individuals to be hybrids which resembled the first crosses
(Ff) in coat and eye colour—i.e. in the possession of a coloured
coat and pigmented eye.

In mating hybrids of this generation (fF) I did not pre-
viously look up their ancestry in books containing their
genealogical record, so that mice of the categories HH and.
HA were mated at random ; in this way three kinds of crosses
were made: HH x HH, HH x HA, and HA x HA. In
each type of union a hybrid was mated with a hybrid, as I
believed at the time; and as on Mendelian theory there is
no difference between the gametic constitution of DR pro-
duced by DR x DR and DR with parentage DR x RR, I
argued ! that, if that theory were true, each type of union
would produce a fraternity, half of which would be composed
of hybrids, a quarter of which would be composed of pink-
eyed mice with coloured coats, while the remaining quarter
would consist of albinos; on the other hand, it was evident
that on Galton’s theory of heredity the proportion would
not only not be the same in each of the three cases, but
would differ in direct proportion to the amount of albino
blood in the parents of the population. The subjoined table
gives, together with the actual result, the proportions of
albinos as predicted by the two theories. In calculating the
Galtonian prediction I have not taken into account any
generations more remote than the great-great-grandparental.?

Type of Number of | Mendelian | Galtonian Actual
Parentage. Young. Expectation. | Expectation. Result,
HH x HH 93 25%, 9°37% | 10°75%
HH x HA 107 25%, 17°96% | 18°69%
HA x HA 121 25% 26°56% | 24°79%

1 Biometrika, Vol. 3, pp. 23-5.
21 thank Mr. J. T. Wadsworth for checking this simple calculation.

148

An Introduction to a Biology

Before continuing my argument, I should like to dwell
for a little on the circumstances which led me to believe
that I was dealing in F, with hybrids, and, indeed, with
heterozygotes in the strict Mendelian sense of the term.
In the first place, these putative hybrids bore the same
features of coat and eye colour as the F, hybrids exhibited ;

_ secondly, they formed 50% of the F, generation; and
lastly, at least two upholders of Mendelian theory! had
asserted that the heterozygote was represented in my ex-
periment by the coloured mice with pigmented eyes.

To resume the thread: these results were brought before
the notice of a student of heredity whose first question was,
Had there ever resulted from the union of two hybrids a
family in which there were no albinos ?—a query to which
an affirmative answer was given. Then the following argu-
ment was used by my critic: “ The only proof that a given
individual is a hybrid is one which is based on an examina-
tion of its gametic constitution; in the case of your mice
you have no right to say that a grey mouse with black eyes
is a hybrid until you have mated it with an albino and obtained
albino young in the litter thus produced; until this has
been done there is no evidence that it is not a dominant.
In the case you have just shown me you mated coloured
mice with dark eyes without making this test, and by this
neglect many dominants may have been included among
them, and you see that this suggestion, against the truth
of which you have no evidence, accounts just as well as
Galtonian theory for the difference in the proportions of
albinos in the three kinds of matings.” I replied that the
test of the true heterozygote nature of the apparent hybrids
should be made, though I did not believe the suggested
Mendelian interpretation of this apparently conclusive anti-
Mendelian result.

The test has been applied with the most remarkable
result ; but before giving an account of it I propose to describe
1 Castle and Allen, “ Proc. Amer. Acad, Arts and Sci.,”’ Vol. 38, No. 21.
149

An Introduction to a Biology

my reasons for adhering to the interpretation of the facts
of this case which I held at first. I believed that all the
individuals in Ff, with pigmented coats and eyes were hybrids,
and that when mated with albinos they would all of them
give some albinos; that the hybrids of F, differed from
those of F, only in degree—namely, that while it was the
property of the latter when mated together to produce as
nearly as possible one albino in every four in their litters,
the former had a less albino-producing capacity ; and that
the hybrids of F, would each be capable of producing still
fewer albinos, and so on with succeeding generations. My
belief was that the hybrids of a given generation—say F;—
would be all the same with regard to their albino-producing
capacity, but would differ from those of F, in having a
smaller one. Before dealing with the origin and meaning
of this view I will relate how, by the application of the test
suggested, 1t was shown to be erroneous. The test of the
real heterozygote nature of the hybrids was made, as sug-
gested, by mating them with albinos. In all cases but two
I found, as I had expected, that albinos were produced ;
and I ascribed the absence of albinos from the other two
litters to chance, and had no doubt that I had only to mate
them with albinos again to obtain the required proof of
their hybridity. But the next litters from the two mice,
mated thus, contained no albinos. So that it began to look
very much as if these apparent hybrids really were dominants.
This fact in itself pointed to the truth of the suggestion that
mice with coloured coats and eyes were of two kinds—
hybrids and dominants; but coupled with the result of
mating the gametically tested hybrids inter se it afforded
fairly complete confirmation of that hypothesis, for of the
92 young resulting from such union, 14 had a pink eye and
coloured coat, 58 a dark eye with coloured coat, while 20
were albinos.

I wish particularly to remind the reader that I do not
think that these numbers are large enough to draw any

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An Introduction to a Biology

numerical conclusions from; they are introduced solely as
part of an argument which is intended to show how I came
to see that the facts summarised in the Table (wide p. 148)
were equally in accord with Mendelian and Galtonian theory ;
and their value in this respect will not be in the least impaired
if it ultimately turns out that the proportion in which the
three categories of coat and eye colour occur are “in every
respect discordant with’? Mendelian prediction.

That the two mice which gave no albinos in the two
matings referred to really are dominant is, I think, placed
beyond doubt by the fact that in a third mating with albinos
they have failed to produce anything but coloured mice
with black eyes.1 That the remaining mice are hetero-
zygotes is also beyond doubt, and that a quarter of the popu-
lation produced by breeding them together is composed of
albinos remains to be demonstrated. The Table on p. 148
therefore is in no wise a refutation of Mendelian theory ;
at any rate, the suggested Mendelian interpretation of the
facts cannot be regarded as disproved. Nevertheless, the
facts are no less in accord with Galtonian theory, though
in a different way than I at first held; the manner in which
I believed that the truth of that theory would be borne
out was, as I have said before, and as I wish eto emphasise
again, by the gradual diminution of the albino-producing
capacity of each hybrid of successive generations. It now
appears that the manner in which that theory is borne
out by these facts is by the gradual invasion of the “ hybrid ”
ranks in successive generations by dominant individuals
bearing the external hybrid characteristics; whether there
will appear among the “dominants”’ or even recessives a
compensating number of hybrids, or even whether this is
demanded by Mendelian theory, is a question of fact which
does not affect my argument. What I want to point out
is that I fell into the error of believing that that which was

1 Besides these two mice which have been tested thrice there are three
which have been tested twice, two bucks and a doe, with the same result.

I51I

An Introduction to a Biology

true of the whole population was also true of the individual
—a mistake which, I believe, was due to an attempt to
discover whether certain phenomena were evidence in favour
of the one or the other of two theories without appreciating
the essential character of either theory and much less their
mutual relation ; to a failure, in short, to realise that a bio-
metric formula of heredity is true only of large masses, the
component units of which in most cases unite at random,
while the Mendelian theory is an attempt to account for
the hereditary phenomena exhibited by the union of in-
dividuals carefully selected, by a theory of the constitution
of their germ-cells. It is perhaps not unnatural, though it
is certainly unjustifiable, that when an experimenter is think-
ing of a set of facts before him now in terms of the one theory
and now in terms of the other without having clearly fixed
the peculiar characters of each theory to its proper owner,
he should get these characters misplaced; that he should
add to the real character of the biometric theory one which
it does not possess—that of applicability to the individual.
I have discussed this particular error of judgment at some
length because it illustrates the kind of mistake a student
of heredity at the present time may make unless he realises
the exact nature, at which I have so far only hinted, of the
two theories whose compatibility with fact he is testing.
Were I not persuaded that mine is not the only case in which
this or a similar kind of error has been made, I should not
have described it; and it is because I believe that the mis-
understandings and arguments at cross purposes, which
have lately characterised discussions on heredity, will be
things of the past when the relation between biometric and
Mendelian theory is clearly seen, that I set forth the following
considerations.

iil

From a point of view which commands a wide range of
our experience, our knowledge may be divided into two
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An Introduction to a Biology

distinct classes, according as we are dealing collectively with
a vast number of things—with a mass phenomenon ; or with
the individual units which make up that mass. These two
kinds of knowledge are radically difierent, and are distin-
guished from one another by the same characters as those
which are peculiar to the two meanings of the statement
that a thing happens by chance; for when we make this
statement we may either be referring to the method by
which I decided whether to write ‘“ biometric” or “ Men-
delian ” first in the title of this paper, or to the result of
a very great number of tosses—an approximation to 50%
heads and 50% tails, which is close in proportion as the
number of trials is great. ‘The first difference that I mention
between these two meanings of chance, as illustrative of
the characters of the two classes into which we have divided
our aspect of things, is that, while in the case of the first
it is impossible to predict the result of a single trial, there
is nothing easier to foretell than the result of a very large
number ; nothing is more uncertain than the former, nothing
more certain than the latter. A second difference between
these two groups is that that which is true of the mass is
not necessarily true of all the component individuals, though
it may be of some; in the case of coin-tossing, the statement
that the result of an infinitely large number of trials is an
equal number of heads and tails is contradicted at every
single toss, though this would not be the case if some of
the coins we tossed had half the head and half the tail on
each side of the coin.! Is it necessary to add that from the
fact that what is true of the mass is not true of the individual
it does not follow that assertions about the individual are
antagonistic to statements about the mass? It is important
to realise this truth because it is seldom done and appar-

1] have found Galton’s apparatus for illustrating the origin of the curve
of frequency (‘‘ Natural Inheritance,” p. 63, Fig. 7) very useful for explain-
ing the difference between these two classes. An example of the first is
afforded by allowing a single shot to run down the inclined board; an
example of the second by displaying the result of a thousand such events.

153

An Introduction to a Biology |

ently difficult, the difficulty resulting from the extreme |
difference of the two points of view. A midge walking
across a picture of a meadow done by the three-colour pro-
cess would assert that it was traversing a white plain, over
which were distributed patches of different sizes and three
colours—red, blue, and yellow; a child would maintain
that it was walking across a picture of a field; each would
be convinced that he was right and the other wrong; yet
that both were right could be recognised by any man able
to use a magnifying lens. This leads us to a third feature
of the relation between our two classes (which results from
the fact that our knowledge has probably developed along
those lines that our point of view has made most valuable),
namely, that in proportion as our knowledge of the com-
ponent units is small so is our knowledge of the mass result
great.

To take an example of these two ways of looking at
things. The climate of a country or of a long period of time
is a mass-phenomenon; the particular climatic condition
of a certain day is referred to as the weather.1 It is, though
it may be becoming less, impossible to predict the weather
with precision; but the nature of the climate of a given
country or long period of time is a matter of tolerable cer-
tainty. Yet the statement that the summer is warm does
not exclude the possibility of a frost nm May. That our
practical knowledge of the elements "is confined to the
climate is evident from the fact that, having procured, we
begin to put on warmer clothing at a certain period of the
year; but if our intelligence were so sharpened, or our
meteorological instruments so improved that we could pre-

1 “* By climate we mean the sum total of the meteorological phenomena
that characterise the average condition of the atmosphere at any one place
on the earth’s surface. That which we call weather is only one phase in
the succession of phenomena whose complete cycle, recurring with greater
or less uniformity every year, constitutes the climate of any locality.”
P. 1.—J. Hann’s ‘‘ Handbook of Climatology,” transl: by R. de C. Wards
1903

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dict the exact state of the weather a fortnight in advance,
we should not procure the warmer raiment until we knew
that it would be needed.

Another phenomenon which may be looked at from these
two points of view is that of the causation of heat; it is
believed that the heat of a substance is occasioned by the
mean speed at which the molecules of which it is composed
are travelling. To deal with the three differences between
our two aspects of things in turn; it is evident first that,
while our ignorance of the speed of an individual molecule
is so great that we try to conceal it by saying that it 1s deter-
mined by chance, our knowledge of the average speed of
myriads of them is so accurate that certain laws of thermo-
dynamics have been formulated. Secondly, it has been cal-
culated that a curve representing the frequency of the various
speeds spread over the molecules is an ordinary curve of
error; so that although that which is true of the mass is
also true of some of the molecules, it is by no means true of
all of them. Thirdly, the only point of view from which
we can regard this phenomenon at present is that from which
we can only discern the mass-result; but that it is by no
means inconceivable that there may be another point of
view is evident to all who are familiar with Clerk Maxwell’s
demon, a being who is so essential to my argument that I
shall make no apology for quoting his creator’s description
of him in full: “ One of the best-established facts in thermo-
dynamics is that it is impossible in a system enclosed in an
envelope which permits neither change of volume nor passage
of heat, and in which both the temperature and pressure
are everywhere the same, to produce any inequality of
temperature or pressure without the expenditure of work.
This is the second law of thermo-dynamics, and it is un-
doubtedly true so long as we can deal with bodies only in
mass, and have no power of perceiving or handling the separate
molecules of which they are made up. But if we conceive

1 My italics,
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An Introduction to a Biology

a being whose faculties are so sharpened that he can follow ou
every molecule in its course, such a being, whose attributes
are still as essentially finite as our own, would be able to
do what is at present impossible to us. For we have seen
that the molecules in a vessel of air at uniform temperature
are moving with velocities by no means uniform, though
the mean velocity of any great number of them, arbitrarily
selected, is almost exactly uniform. Now let us suppose
that such a vessel is divided into two portions, A and B,
by a division in which there is a small hole, and that a being
who can see the individual molecules opens and closes this
hole, so as to allow only the swifter molecules to pass from
A to B, and only the slower ones to pass from B to A. He
will thus, without expenditure of work, raise the temperature
of B and lower that oe A, in contradiction to the second law
of thermo-dynamics.’

The point of view of the demon is so different from that
of the physicist that one of the truest generalisations of the
latter would be declared absolutely false by the former ;
yet no one remains blind for a moment to the fact that the
contradiction of their respective statements is only apparent,
and is due to the radical difference in their points of view,

Now I believe that the difference between the point of
view of the Mendelian and the biometrician is very like the
difference between that of the demon and that of the physicist.
The biometrician, with a new weapon of observation, 1s only
concerned with mass phenomena ; the individuals which go
to swell his correlation tables are, like the atoms of the
physicist, units of which no knowledge is required to attain
the result at which he aims. But I need not dwell on the
exactness of the parallel when we have these words from
‘“‘ the inventor of the term biometry ”’?:1 “ Our ? knowledge
of atoms and our application of atomic and molecular hypo-
theses to problems in heat, elasticity, and cohesion is essen-

1 Nature, Oct. 27, 1904, p. 626.

2 Karl Pearson, ‘‘ Grammar of Science,” 2nd Ed., pp. 500-1.
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An Introduction to a Biology

* tially based on statistics of average conduct. Corpuscles

in each other’s presence are supposed to obey certain laws
of motion, but no explanation has hitherto been given of
these laws. So it is with vital units; they vary, why they
vary we know not, and we explain nothing by attributing
it to bathmic influences. As we can predict little or nothing
of the individual atom, so we can predict little or nothing
of the individual vital unit. We can deal only with statistics
of average conduct. We have laws of variation and laws of
heredity, in themselves quite as general and as definite as
the majority of those we meet with in physics.”

I may perhaps take this opportunity to explain that I
have used the term biometric theory advisedly, and that
the definition of it that I have had before my eyes is not
merely “the application of exact statistical methods to the
problems of biology,” 1 but the aspect of vital phenomena,
just quoted from the “ Grammar of Science,” which prompts
that application. |

And I believe that I am justified in including under the
term “biometric”? both Pearson’s and Galton’s theories
which, though in one respect they are radically different,?
resemble each other in regarding heredity as a mass-pheno-
menon and in treating it by the statistical method.

The Mendelian, on the other hand, with a new appli-
cation of experiment, is a biological demon who, “ perceiving ”’
and “handling the separate”? units themselves, tries to
find out their properties by mating them with other units,
But here again I need not expatiate on the closeness of the
parallel I have suggested when we have these words from
the champion of Mendelism in this country : * “ In the Men-
delian method of experiment the one essential is that the
posterity of each individual should be traced separately.

1 Nature, Oct. 27, 1904, p. 626.

2 Karl Pearson, Biometrika, Vol. 3, pp. 110-11.

8 Presidential, Address to Section D, Brit. Assoc., 1904, in Nature,
August 25, p. 409.

137

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An Introduction to a Biology

If individuals from necessity are treated collectively, it must
be proved that their composition is identical. In direct
contradiction to the methods of current statistics, Mendel
saw by sure penetration that masses must be avoided.”

There is one direction in which my parallel may seem
at first sight to be incapable of being pushed very far; it
may be urged that we never can have any knowledge of
the individual, but only of kinds of individuals, because in
single cases it is impossible to eliminate the attributes which
are due to chance; so that Mendelian methods are more to
be compared with chemistry, which tests the property, not
of units, but of masses of units which are known to be all
the same.! But this fact does not in the least lessen the
closeness of the parallel, for we have no reason to believe
that the demon, if his attributes are as “ essentially finite
as our own,” would have or need any knowledge of the
individual molecules, but merely the ability to classify them
into, say, ten classes, ranging from very fast to very slow,
and to close his door according to their speed and direction.
This point does not seem to be of much importance, but I
did not wish, by not referring to it, to appear to have over-
looked it.

One result, which seems to me to follow naturally from
the truth of my comparison, is that it is unreasonable to
apply, as has often been done, the criteria of either theory
to a set of facts in which the conditions, on which that theory
is true, do not obtain; and the manner in which materials
for the study of heredity are collected by Mendelians is so
different from those employed by biometricians that this is
very rarely, if ever, the case.

From this it follows that the naturalist who sets out to
attack the problem of heredity will not as in the past collect
his facts and then see whether they fit the one theory or

1 Of. ‘“ The breeding-pen is to us what the test-tube is to the chemist ”
—same Address, p. 409, first column; and cf. “ Reports to Evol. Com-
Royal Soc.,”’ I., p. 159.

158

i %
4

An Introduction to a Biology

the other, but will make it his first duty to decide whether
he will attack it from the point of view of the physicist or
the demon, from the outside or from the inside. If he
decides on the former, he may if he wishes, breed his material,
but he will find a great deal ready to hand in the records
of matings of, for example, greyhounds, racehorses, and men.
If he decides on the latter, it is almost indispensable that
he should breed his material for himself. That is why
biometricians are concerned with “ancestry,” and Men-
delians with “posterity.” Yet these are not two things,
but one thing, looked at from opposite ends. But there is
a difference between ancestry and posterity, namely, that
the latter only can be dealt with by the method of experiment.

A confirmatory sidelight on the truth of my comparison
is thrown by the consideration that of the two men whom
I have quoted as representing the rival theories of heredity,
the biometer is a mathematician, while the Mendelian is a
zoologist ; and it is entirely in accord with expectation that
the former regards the phenomena of heredity from that
point of view which does not presuppose knowledge of the
unit, while the latter is concerned with the properties of the
individual organism.

If we could imagine the demon and the physicist in-
capable of appreciating each other’s point of view, we could
understand the contempt each would have for the clumsy
methods and erroneous opinions of the other.

And though we can perhaps understand the Mendelian
declaring as he slides the latch of his breeding-pen that
‘Operating among such phenomena the gross statistical
method is a misleading instrument; and, applied to these
intricate discriminations, the imposing Correlation Table
into which the biometrical Procrustes fits his arrays of un-
analysed data is still no substitute for the common sieve of
a trained judgment”; and that “nothing but minute
analysis of the facts by an observer thoroughly conversant
_ with the particular plant or animal, its habits‘and properties,
tat 159

Shp
-
iy

An Introduction to a Biology ~

checked by the test of crucial eaideisneah, can disentangle
the truth ” ; 1 and appreciate the point of view of the bio-

meter seuhalioues his vast arrays when he contends that.

it is “better to use the purely descriptive statements of

Galton and Pearson than to invoke the cumbrous and un- —

demonstrable gametic mechanism on which Mendel’s hypo-
thesis rests.” 2 I do not see that we have any right to remain
blind any longer to the fact that the contradiction of their
respective theories is only apparent, and is due to the radical
difference in their points of view.

1 Pres. Address to Sect. D. Nature, August 25, 1904, p. 408.
Nature, Sept. 29, 1904, p. 539.

9 a
tips

a

ny

_ An Introduction to a Biology
APPENDIX. (See p. 146.)

e

«

= Facts.
" ¢

”

**'Versuche iiber Pflan-

zen - Hybriden,” by
Gregor Mendel. Ver-
handl. naturforsch. Ver.
in Brtinn, Vol. 4, 1865.
Abhandl. p. 1. Transl.
into Engl. in “ Men-
del’s Principles of Here-
dity,”’ by W. Bateson.

.
.

gen von verschiedenen
Rassen der Haus-
maus,’ by G. von
Guaita. Ber. d. natur-
forsch. Gesell. Freaburg,
x., 1898, p. 317. Zweite
Mitth., etc., Ibid. xi.,
1900, p. 131.

.
.

mentation chez les
Souris ” (3™° Note), by
L. Cuénot. Arch. de
Zool. exp. et gén., 1904
(4), Vol. 2. Notes et
Revue, No.3, pp. 45-56.

ca
a

ing Japanese Waltzing
with Albino Mice,” by
A. D. Darbishire. Four
Reports. Biom., Vol. 2,
pp. 101, 165, and 282.
Vol. 3, p. 1.

Versuche mit Kreuzun-

* THérédité de la Pig-

On the Result of Cross-

Mendelian I nter pretation

(i.) Mendel, G., p.

72, in Engl.
transl. by Bate-
son.

(ii.) Bateson, W.
Mendel’s Prin-
ciples, p. 57 et
seq.

(i) Bateson, W.
Proc. Zool. Soc.,
1903, Vol. 2,

pp. 86-8.
(u1.) Castle, W. E.
Proce. Amer.

Acad. Arts and
Sct., Vol. 39,
No. 8, p, 231,
Table II.

Cuénot, L. loc. cit.

(i.) Bateson, Ww.

Proc. Zool. Soc.,
1903, Vol. 2,
p. 88.

(ii.) Castle, W. E.,
and Allen, G.
M. Proc. Amer.
Acad. Arts and
Sci., Vol. 38,
No. 21.

(iii.) Bateson, W.
Nature, Vol. 67,
pp. 462, 585;
68, p. 33.

161

Biometric
Description.

Weldon, W. F.

R. Nature,
Vol. « 70," ° p.
539.

Weldon, W. F.
R. Nature,
Vol) Tin.
539.

|

|

(i.) Darbishire ,

A. D.,; we
cut.
(ii.) Weldon, W.
F. R.
(a) Biom., Vol.
2, p. 286.
(2) Nature, Vol.
67, pp. 512,
610; 68, p.
4.

LV

The Laying Bare of the Marvel—A Legend
(The Manchester University Magazine, April, 1905)

Ir was in the days when men said, “‘ This is an age of civilisa-
tion’; but their words were not true. For it was a time
when things were, as they say, “ topsy-turvy” ; when those
who did much work had little goods, and those who did none
at all were fat and rich and clothed in the furs of animals;
it was a time when the exchange of goods was greatest
between those in whom the desire for goodness was least,
when those who had great store of goods drave in chariots,
noiseless, dragged by horses, and when those who were richer
still and more wicked drave in chariots, noisy, driven by
spirits. But I speak not of these because I know them not ;
but of those who do much work, and have no stores; for
they busy themselves with many things, and derive pleasure
from wondering how those things which they see round
about them have come to be. And the greatest pleasure
amongst them is to discover how such things come to pass,
and the greatest foolishness amongst them is to think they
can discover why. Now of such folk there are two kinds—
one kind which busies itself with things that are dead and
have never been alive ; and another whose delight is in things
which are alive but which do not remain so for long. The
knowledge got by the first is necessary to the labours of
the second; but the knowledge got by the second is not

1 This fable is an account of the Cambridge debate on Heredity at
the British Association Meeting, 1904, in which Mendelians and Biometri-
cians disputed. Petturcha=A. D. D.

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An Introduction to a Biology

necessary to the labours of the first. But those that are
busied with dead things and those that are busied with the
living agree with one another in this, that they desire that
there should be orderliness in the things with which they
deal. And behold, this desire is so strong within them
that they do not rest until they have discovered, in those
things with which they deal, this order, this regularness.
But more words must be spoken of the dead things, and
more of the living. Now wizards declare that all things
both living and dead are made up of things so small that
they cannot be cut up, and so small that they cannot be
seen, and so small that unbelievers in these matters have
said, “‘ They are not.”

The things (or as some say, the units) with which those
that treat of the dead are busied are these things that can-
not be cut up; and the things with which those that treat
of the living are busied are not the things so small that
they cannot be cut up, but things so large that they can
be, and often are, cut up: herbs and beasts. Nevertheless,
they are made up of the invisible things which cannot be
cut up; and that is why, on the one hand, the knowledge
of the wizards of the dead is necessary to the labours
of the wizards of the living; and why, on the other hand,
the knowledge of the wizards of the living is not necessary
to the labours of the wizards of the dead. And when a
wizard of the living asks a wizard of the dead, ‘‘ What are
the things which cannot be cut up like; and what do they ?”
he makes answer, “ Wullahy! we know not what any one
of them is like; and we know not, neither can we foretell
what any one of them will do; but we know very surely
what a vast multitude of them is like, and can foretell what
it will do.” And when a wizard of the dead asks a wizard
of the living, “ What like are your things which can be cut
up, your herbs and beasts? Can it be so that you can see
and handle them and know their virtues ? ” he makes answer,
“Very truly this is so; and it is our chief desire to know

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An Introduction to a Biology

what like is each one in itself and in its relation to others.
It is as if I were a shepherd of much experience and a thou-
sand sheep; I live among them and tend them, and know
the face of each one of them; while you are a shepherd
of no experience with a thousand thousand sheep. I know
the properties of every sheep, while you trouble yourself
only with the properties of flocks.” Now this was spoken
in a friendly manner, but the wizard of the dead went away,
saying, “I do not understand your words, and I had rather
have a knowledge of flocks than be the companion of sheep.”
Surely there was no justice in his wrathful taunt; but it
is often thus. Now it is established that the greatest differ-
ence between the things which cannot be cut up and the
things which can be and often are, is that the first are always
the same, indestructible, undying because they are never
alive, and that the last are destructible, mortal, but con-
tinuing through the ages by begetting young after their
kind; for beasts do not beget herbs, nor herbs beasts; nor
even one kind of beast another kind of beast; but beasts
of certain kinds beget beasts of the same kind, or nearly ;
and herbs of certain kinds beget herbs of the same kind, or
nearly. Now this likeness of the generation begotten to
the generation which begat it was a marvel for all time;
but it was not till the time of which we have spoken, the
time when men lied, saying, “ There is civilisation,” that
wizards said to themselves, ‘‘ What is this marvel, and what
are the inward workings of it?” And so great was the
desire to discover the secret that both wizards of the dead
and wizards of the living were fired with it. Now it must
be remembered that in all wizards the passion to discover
an orderliness in the things with which they busy themselves
is very great; and the wizards of the dead asked, “ How
can we discover an orderliness in this marvel of the things
which can be cut up?” and they answered themselves, “ In
the same way as we discover it in the things which cannot
be cut up.” So, forthwith they gathered vast records of
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An Introduction to a Biology

the likenesses of sons to fathers and sons to grandfathers,
and of daughters to mothers, and daughters to grandmothers ;
and they busied themselves in this way with men, and with
horses and with dogs; and then they said, ‘“ Behold we,
the life-measurers, have discovered an orderliness in this
marvel, and we are satisfied.”” But the wizard of the living
did not hearken. For they were trying to discover an order-
liness in the marvel; in the manner in which they were wont,
namely, by busying themselves, not with large collections
of things, as the life-measurers do, but by finding out the
properties of each of the different kinds of herbs and beasts,
and how they are passed on from father to son. Now they
believed that a key which would unlock the secret of the
marvel had been given them by a certain priest who had
remained obscure for a long time;1 so that the wizards of
the living who sought to find an orderliness in the marvel
were called followers of the priest; and the wizards of the
dead who sought the same thing were called life-measurers.

At the time of the year when the sun is hottest and the
thunder rolls there was a great gathering together of wizards
on the banks of a narrow and sluggish river which flows
through a flat and swampy region of a certain island. There
were many dwellings near the river; some were old and
others were new; and in one of the new ones on a certain
day there gathered together the life-measurers and the priest-
followers; and the great chief of the life-measurers was
there, and the great chief of the priest-followers was there, and
their names are too sacred to be breathed. There was also
there one Pettrcha, who tarried in the hut of one of the
kindest and most jovial of the wizards ; Pettircha was young ;
he was not a chief, but he marvelled at the marvel. In the
dwelling, at the appointed time, words fell from the mouth
of the chief of the priest-followers which were not pleasing
to the life-measurers; and that which the chief of the life-
measurers said found no favour with the priest-followers ;

1 Mendel.
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and each party said, ‘‘ We are right”; and each party said,
“You are wrong.” But Petircha said, ‘“‘ Both may be
right,” and he found favour neither with the life-measurers
nor with the priest-followers. And the wizards departed
from the banks of the sluggish river, without having laid
bare the marvel. And Pettircha came back to the banks
of another river, whose waters were black and sluggish,
and on whose banks there are many huts; and though
the huts are black the dwellers in them are not sluggish.
He came back to the wizard who was his chief, the chief who
by the other river sat upon the fence-work and was not
sealed a priest-follower, and was not sealed a life-measurer.
And Petircha, who was likewise not sealed, sent forth word
saying, “ There are two ways of busying with the marvel :
the way of the wizards of the dead, and this is done by
life-measurers; and the way of the wizards of the living,
and this is done by the priest-followers; it is for a man
to choose which way he will pursue; but if he thinks the
way which he chooses not is wrong, his thoughts are
wrong. There is no strife between the two ways.” But
save from a few there came no answer.

These things happened in the days when civilisation,
rising in the east, had not spread over the face of the earth.

166

hs

On the Difference between Physiological and
Statistical Laws of Heredity

(Manchester Memoirs, Vol. l., 1906, No. 11.)

§ 1. Introductory.—§ 2. Statistical Laws: (a) Pearson’s Law ; (6) Gal-
ton’s Law ; (c) The difference between the two.—§ 3. Physiological
Laws: (a) The Law of Diminishing Individual Contribution; (b)
Mendel’s Law; (c) The difference between the two.—§ 4. The
difference between statistical and physiological Laws: (a) The
former “ descriptive”: the latter “explanatory” ; (b) Mendel’s
Law true of units: Pearson’s of masses; (c) Examples of the
confusion between physiological and statistical Laws; (d) De-
scription of a method of dealing with the material of a breeding
experiment in such a way that the data obtained may be used
to test the validity both of Mendel’s and of Pearson’s Law;
(ec) Why do white sheep eat more than black ones ?

§ 1
THERE are those who maintain that it is not the part of
the biologist to argue, to discuss, and to explain; and who
assert that he is transgressing his proper limits when he
ceases to confine himself to the description of observations
and experiments, and to drawing from them certain obvious
conclusions.

I do not hold this opinion: because I am convinced
that if as much (I do not say more) trouble were taken to
understand the meaning of a term as is spent in establish-
ing the authenticity of a fact, the progress of our know-
ledge of fundamental natural processes—heredity, variation,
the determination of sex, to name a few—would be more
rapid than it is at present. For it seems to me to be evident

167

<a
a“

An Introduction to a Biology

that nothing short of a firm but unprejudiced grasp, in
the mind of the investigator, of the relation between the
facts themselves and past, present, and possible attempts
to account for them can enable him to advance toward a
closer knowledge of these phenomena.

I think that the reader will admit the truth of this con-
tention, if he is not one of those who still cling to the
Baconian delusion that all that is necessary for the elucida-
tion of the problems of nature is the bringing to light of
as many facts as possible by as many workers as possible ;
whereas, as a matter of fact, it is obvious that that which
hinders the progress of natural knowledge is not the slow-
ness with which facts are brought to light, but the paucity of
investigators capable of dealing with them properly.

The incapacitating fault among biologists which is at
once the commonest and the most serious is the unconscious
ease with which they fall into the error of using a term with-
out having previously ascertained its meaning. And so long
as biologists turn a deaf ear to speculation, this disease will
flourish. That which is necessary, therefore, to make
progress both surer and swifter is a greater aptitude to for-
mulate a clear idea of the meaning of the terms which are
employed—a habit of mind which is not likely to be common
so long as the consensus of biological opinion regards with
less favour the attempt to discover the essence of a newly
suggested hypothesis, than the attempt to describe the
course of the vas deferens in a newly discovered worm.

In the study of heredity in particular the most extra-
ordinary confusion has resulted from the fact that not
only has the same term been used to mean different things
by different writers, but very often has had many significa-
tions in the writings of a single author. This state of affairs
is due, in my opinion, to the absence of any patient and
laborious attempt to thresh out the meanings of the terms
continually on the lips of those who take part in the dis-
cussion of this subject ; and this absence is due in its turn

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An Introduction to a Biology

to the callousness, if not disfavour, with which such an
attempt is likely to be regarded. Nevertheless I propose
to make it.

§ 2

Space forbids me to discuss the question of the advisable-
ness of using the term “law” at all as summarising vital
phenomena, more than to say that the fact that I use it
166 times in this paper demands some apology.

I use it because, besides possessing the advantage of
brevity, it is of all terms in biology the vaguest; signify-
ing as occasion demands either a theory, or a résumé, or a
hypothesis, or a formula, or a generalisation—to name a
few of the more or less legitimate senses in which it is used :
and because it shelters, under its wide roof, Laws whose
authors aim at explanation, and those whose authors are
satisfied with description. And I spell it with a capital L
because that is the conventional way of writing terms the
discussion of whose meaning is postponed.

(2) Prarson’s Law

No one has any excuse for not knowing what the Law of
Ancestral Inheritance is; the essential features of it are
outlined by Pearson in the following words :—

“Taking our stand then on the observed fact that a
knowledge neither of parents nor of the whole ancestry
will enable us to predict with certainty in a variety of im-
portant cases the character of the individual offspring, we
ask: What is the correct method of dealing with the prob-
lem of heredity in such cases? The causes A, B, C, D, £,

. which we have as yet succeeded in isolating and
defining are not always followed by the effect X, but by any
one of the effects U, V, W, X, Y. We are, therefore, not
dealing with causation but correlation, and there is_there-
fore only one method of procedure possible ; we must collect
statistics of the frequency with which U, V, W, X, Y, Z
respectively follow on A, B, C, D, HE... . From these

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An Introduction to a Biology

statistics we know the most probable result of the causes
A, B, C, D, E and the frequency of each deviation from this
most probable result. The recognition that in the existing
state of our knowledge the true method of approaching the
problem of heredity is from the statistical side, and that
the most that we can hope at present to do is to give the
probable character of the offspring of a given ancestry, is
one of the great services of Francis Galton to biometry.” }

(b) Gatton’s Law

Galton formulated his Law as follows: ‘‘ The two parents
contribute between them on the average one-half, or (0-5) of
the total heritage of the offspring; the four grandparents,
one-quarter, or (0°5);? the eight great-grandparents, one-
eighth, or (0°5),3 and so on. Thus the sum of the ancestral
contributions is expressed by the series {(0-5) + (0-5)? + (0-5),3
etc.}, which, being equal to 1, accounts for the whole heri-
tage.”

(c) Tur DIFFERENCE BETWEEN PEARSON’S AND GALTON’S
Law

It will be seen how profoundly Galton’s differs from
Pearson’s Law. Yet the belief that the two are much the
same is not rare, and the statement that the latter is merely
an extension of the former is often made. A clear apprecia-
tion of the difference between the two is necessary to any-
one who wishes to be conversant with modern theories of
heredity.

One feature the two have in common: both of them are
true only of masses, and do not pretend to apply to indivi-
duals. This is so obvious to the careful thinker that Pearson
only refers to it in a footnote ;? yet it is often forgotten.

The difference between the two lies in this: Pearson’s Law
measures the degree of correlation between a character or

characters in a given generation, and some similar (or dis-

1 Pearson, :03a, p. 215. ? Galton, 97, p. 402. * Pearson, :04, p. 161.
170

°

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A.

An Introduction to a Biology

similar) character or characters in the preceding generation.
Galton’s Law states the amount which a given generation
contributes 1 to the generation which it produces. It defi-
nitely states that on the average a half of the filial genera-
tion are like the parental, a quarter like the grandparental,
and an eighth like the great-grandparental, and so on. From
the knowledge that the parents of a given generation of cats
are tabbies, and that half of its grandparents are tabbies,
a quarter whites, and a quarter blacks, you are enabled to
predict by Galton’s Law the proportion in which these three
kinds of cats will occur in that generation. Pearson’s Law
does not enable you to do this: it is of an entirely different
kind. For Pearson’s Law to be true it is not necessary that
any of the children should be like any of the parents; all
that is necessary is that a particular kind of parent should
be associated with (i.e. should produce) as often as not a
particular kind of child. On the next page is an imagi-
nary Correlation Table, in which Pearson’s Law is borne
out, yet in which none of the children are like any of the
parents.

The fact that the relation between a given generation
and those that precede it is described by a series of figures
which in the case of Galton’s Law is -5, -25, -125, -0625, etc.,
and which in the case of Pearson’s, for eye colour in man,
for example, is -4947, -3166, -1879,? has led some to believe
that the figures mean the same thing (which, of course, they
do not) and has thus constituted a trap for the unwary.
Castle has done good service to progress in the study of
heredity by falling into it.®

I hope I have made clear what the difference be-
tween the meanings of the two series is; for to under-
stand this is to understand the difference between the two
Laws.

This difference is sometimes expressed in the statement
that Pearson’s Law is more comprehensive and less bio-
1 See Appendix B, p. 197. * Pearson, :03a, p. 221. * Castle, :03, p. 224.

171

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An Introduction to a Biology

FATHERS.

Dark Pale
Black. Grey. Grey. Grey. White. Totals.

Purple. 3 1

Blue.

CHILDREN.
a”)
c
a
B.
lor)

Totals. 17

The degree of correlation in the above Table is that between
the number of dice exhibiting 4 or more than 4 points (or “ pips ’’)
uppermost in first throws, and the number exhibiting those
faces uppermost in second throws, in a series of 300 double
throws. The two throws are correlated by leaving half the
first throw on the table, so that the second throw has half the
dice lying exactly as they fell in the first throw. For details
of this process the reader is referred to Weldon :06, p. 100.

The degree of correlation in my imaginary Table is °54 ;
for calculating which I am indebted to Mr. Udny Yule. The
‘‘ coefficient of parental heredity,” therefore, in this case is
identical with that for the inheritance of deafness, of which
Pearson’s Law is true, recently worked out by Schuster (:06,
p- 478). Yet, in my imaginary case, none of the children could
be mistaken for any of the parents.

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An Introduction to a Biology

logical! than Galton’s; and inasmuch as it embraces sets
of facts which are not described by Galton’s formula, the
first of these statements is true; and inasmuch as the rela-
tion between successive generations which it measures is
the same as the relation between two series of throws of
dice (in which reproduction is unknown), of which every
throw of the second series consists of half the dice lying
exactly as they fell in the corresponding throw of the first
series, the second is true also.

§ 3
(2) THe Law or DiminisHinc [INDIVIDUAL CONTRIBUTION

In my paper on the supposed antagonism of biometric
to Mendelian theories of heredity, I showed that a set of
facts (summarised in the Table, wide p. 148 supra), appear-
ing at first to be a complete refutation of Mendel’s Law,
could easily be shown to be equally in accord with both
Mendelian and Galtonian theories.2_ Mendel’s Law describes
the individual phenomena in this case perfectly: Galton’s
Law describes the mass result composed of these very indi-
viduals mating at random perfectly. The latter describes the
proportions, the former accounts for them. The Galtonian
deals with individuals from the point of view from which
the physicist deals with atoms; the Mendelian deals with
them from that of Clerk Maxwell’s demon.

Now just at the same time that I announced my discovery
that the proportions of the albinos in this case were not
evidence against the truth of Mendel’s Law,* Castle made
the same discovery. But he argued from his discovery,
not (as I did) that the two theories were compatible but
that Galton’s was wrong; that is to say, he must have
thought that the two theories were mutually exclusive ;
which indeed he did: but not in the same way that I did.

1 Fruwirth (:05, p. 147) goes so far as to say that ‘‘ das Ahnenerbengesetz
ist kein biologisches Gesetz. . . .”
* Darbishire, :05a, p. 6, 3 ibid., 05a, p. 9. 4 Castle, :05, p. 17 et seq.

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An Introduction to a Biology

For whilst the way in which I made that error was by lift-
ing Mendel’s Law from the level of a would-be explanatory
to that of a purely descriptive Law, he made it by lowering
Galton’s from the level of a purely descriptive to that of a
would-be explanatory one. And the reason that I dis-
covered my mistake before he did was that it is easier to see
that Mendel’s Law is something more than a purely descrip-
tive one, than it is to see that Galton’s is not a would-be
explanatory one. And the reason again of this is that
Galton’s Law is confused with another one which resembles
it in one respect, but differs from it in being would-be ex-
planatory. The remarkable thing about this Law is that
whilst it is characteristic of most Laws to be enunciated and
receive a name first and then become widely believed in after-
wards, the reverse is the case with this one; for it is believed
in by all biologists who are not Mendelians, by all breeders
of animals or plants, and by all persons not belonging to
these classes who think about heredity at all.

But it has not yet received a name. I propose to call it
the Law of Diminishing Individual Contribution.

According to it: the germ plasm of an indiwidual contains
contributions from all of its progenitors: the amount of the
contribution being large in proportion as the progenitor is
near, i.e. large in the case of the parents, smaller in the case
of the grandparents, and so forth.

It is a very good type of biological Law: it has the
advantage of simplicity: it is also, except in a few cases,
untrue.

I will now give three cases to show how widespread
belief in this Law is.

The first that I give is that of the result of crossing a
yellow and white pink-eyed Japanese waltzing mouse with
a pink-eyed white mouse—that is, an albino. The result is,
usually, a black-eyed grey mouse.1 And to anyone not
familiar with it, the result is most astounding : it is quite the

1 Darbishire, :04a, p. 7.
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An Introduction to a Biology

opposite of what one would expect. Expect from what ?
From one’s—possibly unconscious—belief in the Law of
Diminishing Individual Contribution.

Another case. Now that we know that a blue Anda-
lusian fowl is a heterozygous form produced by mating a
black and a white, and that Andalusians when mated
together produce 25% Blacks, 50% Andalusians, and 25%
Whites, we no longer try to get a pure strain of Andalu-
sians by throwing away the blacks and whites and by con-
tinuing to breed from the Andalusians for many genera-
tions, because we know that we can always get Andalu-
sians and nothing else by mating blacks and whites.1| What
is the conception of heredity which underlay the old-fashioned
attempt to breed pure Andalusians by weeding out the
blacks and whites, but the Law of Diminishing Individual
Contribution ?

Again, Coutagne,? in discussing the possibility of the
hybrid nature of some dark-lipped individuals of Heli
hortensis, which occurred in a collection of that species and
Helix nemoralis living in one locality, concluded from the
fact that these supposed hybrids were unbanded, whereas
the great majority of the H. nemoralis in that locality were
banded, that they were not hybrids. To translate his own
words, “If the H. nemoralis were the parents of the 113
black-lipped individuals there is every reason to believe
(tout porte a présumer) that this character of banding would
appear at least in some cases in these 113 individuals.”
Through Lang’s ® work we know now that in a cross between
a banded H. nemoralis and an unbanded H. hortensis the
unbandedness is dominant. So that now we should not
expect “this character of banding” to appear in any of
the individuals: and Coutagne’s argument falls to the
ground.

But what is “tout porte d présumer” but the expectation

1 Punnett, :05, p. 28. 2 Coutagne, :95, p. 72.
3 Lang, :04, p. 497, and :06 (see also Darbishire, :050, p, 196).
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An Introduction to a Biology

based on a firm belief in the Law of Diminishing Individual
Contribution ?

These three cases show how widespread is belief in this
Law; and they also show that in these three cases at least
it is not valid.

The difference between the expectation based on this
Law? and the accurate knowledge of what actually takes
place (which it is the business of Mendelian investigation
to supply) is the same as the difference between common
sense and science, and the same as the difference between
that which stands to reason and that which rests on
evidence.

(6) MenpEL’s Law

I do not propose to discuss here the statement that the
time has not yet come when we are justified in speaking
of Mendel’s Law, nor to inquire into the meaning of this
statement: the question I propose to answer is, ‘* What
is the essential feature of that which is called Mendelism
by those who believe in it, and Mendelianism by those who
do not?”

I divide definitions of the Law into two primary cate-
gories :—

(i.) Suitable for those who desire to establish the
invalidity of the Law.

(ii.) Suitable for those who wish to discover whether
Mendelism has helped us or is likely to help us
to attain to a more intimate knowledge of
heredity.

There is no difficulty in finding a definition of the first
class: a very satisfactory one is one which binds the Men-
delian down to the Law exactly as enunciated, and the
description of the phenomena exactly as given by Mendel

1 Huxley must have been thinking of some such Law as this when he

made the remarkable statement that science was organised common sense.

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An Introduction to a Biology

himself. If this is carefully done, no difficulty will be en-
countered in establishing the invalidity of Mendel’s Law
as facts accumulate.

To discover a definition of the second class is not so
easy. To my mind, there are two perfectly distinct things
included under the one term Mendelism. One is belief in
the existence of character-units in the germ, and in the
thesis that these units are pure in respect of the characters
which they represent. The other is the method by which
the extent, separateness, and transmission of these units
is discovered. The first may be called the Mendelian theory,
the second the Mendelian method—which is the application
of the experimental method to the study of heredity. I
think that both these things are implied when the term
Mendelism is used; and whether they are or not—and it
does not in the least matter—I believe that the Mendelian
method will do as great service, in accounting for the pheno-
mena of heredity, as that particular theory which Mendelians
happen to be employing at the moment.

For I think that it must be evident to anyone who has
followed closely the Mendelian work of the last few years
that, while the method which workers of that school have
employed has remained the same, the actual theories, by
testing the validity of which they have sought to attain
their end, have been from time to time considerably modified.
This procedure, of course, makes it difficult for those who
wish to criticise or base statistical calculations on the theory
itself. Pearson comments on it in these words: “ The
original Mendelian theory has been replaced by what are
termed ‘Mendelian Principles.’ In this aspect of investi-
gation the fundamental principles propounded by Mendel
are given up, and for each individual case a pure gamete
formula of one kind or another is suggested as describing
the facts. This formula is then emphasised, modified, or
discarded, according as it fits well, badly, or not at all with
the growing mass of experimental data. It is quite clear

M 177

An Introduction to a Biology

that it is impossible while this process is going on to term
anything whatever Mendelian as far as theory is concerned.” +

But should we be right in refusing to commend the
efforts of a well-digger if, in sinking his well, he alternately
used a spade, a pickaxe, and dynamite, according as he
had to deal with gravel, sandstone, or granite, provided
that he found, or even that he thought he would find, water
at last ?

The aims of the Mendelian and the well-sinker are the
same—to discover something; and they each employ a
definite method, but the tools they use are continually being
changed. That is why I think that the method is at least
as essential a part of Mendelism as the theory. And that
is why I think that there is no more connection between
Pearson’s generalised theory of alternative inheritance (with
special reference to Mendel’s Law), and Mendelism, than
there is between the second law of thermo-dynamics and
the Maxwellian demon’s knowledge of atoms plus the method
by which he has acquired it.

There zs a definite relation between a generalised theory
of alternative inheritance and that particular doctrine on
which it is based: it is the same as the relation between
the second law of thermo-dynamics and the theory held,
ex hypothest, by the demon as to the nature of the atom.

But there can be no relation between any generalised
theory of inheritance and Mendelism? unless that term
signifies the Mendelian theory only; and, even so, this re-

1 Pearson, :03), p. 53.

*I do not, of course, intend to imply that Pearson tries to establish
any relation between a generalised theory of inheritance and Mendelism :
I know his was a generalised theory of alternative inheritance based on the
theory of the pure gamete. All I wish to insist on is that the theory which
Mendelians happen to be testing at the moment is, to my mind, not the
essential thing in Mendelism. If the commonly accepted explanation of
the proportion 1DD : 2DR : IRR were shown to be false, would experi-
ments, called Mendelian, now in progress be prosecuted with less zeal ?

By no means. Such a discovery would even be an incentive to more
strenuous search.

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An Introduction to a Biology

lation cannot be permanent unless the Mendelian is pledged
not to change his theory in the smallest degree. I hold
that, in the first place, Mendelism has, as I have shown, a
wider signification—namely, that it embraces the method
as well; and secondly, that no Mendelian can be expected
to take the pledge demanded, if by doing so he believed,
as he probably would, that he would be prevented from
attaining his end. It is idle to accuse him of inconsistency.
What should we think of the consistency of a well-digger
who died of thirst because he would stick to his spade although
only a few feet of granite separated him from water ?

And what right have we to expect that the demon should
pledge himself not to alter his theory of the nature of atoms,
if he hopes that by being free to alter it he will attain a
knowledge of them that will enable him to live in a warm
compartment without having to do any work for it? What
right has a physicist to expect a demon not to alter his
theory, on the ground that such an alteration makes it
exceedingly difficult for him (the physicist) to use the theory
as a basis for statistical calculation ?

(c) THe DIFFERENCE BETWEEN MENDEL’s Law AND THE
Law oF CONTRIBUTION

Now that we come to discuss the difference between
Mendel’s Law and the Law of Diminishing Individual Con-
tribution, we must clearly understand that by Mendel’s
Law we mean the theory associated with that name, and
not the method.

These two Laws resemble each other in being physiological,
in that they attempt to picture the way in which characters
are represented in the germ-cell. But they differ profoundly
in the picture which they draw. The difference is so obvious
that it is hardly necessary to speak about it. A remark
on the difference between the predictions of the two Laws
as to the nature of the offspring of extracted recessives will
suffice. Suppose that two hybrid mice with grey coats

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An Introduction to a Biology

and black eyes were to produce an (extracted) albino—
which, if the Law of Contribution were true, they could
not do: the Mendelian prediction about the offspring of
a pair of such albinos is that they will be all albinos; the
expectation based on the Law of Contribution is that a
quarter of the coat of each individual child will be grey—
supposing the proportions for individuals in which each
progenitor contributes, according to that Law, to be the
same as that demanded for populations by Galton’s. The
Mendelian prediction is right.1_ In fact, the Law of Con-
tribution is so utterly invalid that every case of alternative
inheritance is a contradiction of it. It may apply to some
cases of blended inheritance. But the reason that I have
formulated it and given it a name is not that it may perhaps
apply to one or two cases, but because, unless it is definitely
enunciated, it will not be reckoned as having any claims
to recognition, and because, the sooner it is widely recognised,
the easier will it be to put an end to its confusion with Galton’s
Law.

§ 4
(a) SratisticaL Laws, “ DESCRIPTIVE”; PHYSIOLOGICAL
Laws, ‘‘ EXPLANATORY ”

The remark might be made about the Law of Contribu-
tion that it is Galton’s Law made applicable to the individual ;
and this in a sense is true, but there is a profound differ-
ence between the two, for whilst the Law of Contribution
is an attempt to picture the way in which characters are
represented in the germ-cells of individuals, Galton’s Law
is merely a statement that the characters of the ancestry
of a population reappear in certain definite proportions in
that population. It is only concerned with that which
is above the horizontal line AB in the figure on p. 182,
Moreover, it is only true of the aggregate of adults,
and not of the individuals which compose that aggregate.

1 Darbishire, :04a, p. 23.
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An Introduction to a Biology

The Law of Contribution, on the other hand, deals with
that which is below as well as with that which is above
the horizontal line, and it is true of the individuals.

Now, although Galton’s Law is true of the mass but
not of the component individuals, the Law of Contribution
is true of the individuals and of the mass as well, because
according to it all the individuals are contributed to, in
the same degree.

The widespread belief in the existence of a Law which
is true both of mass and individual is the result of the inter-
action of two outstanding characters of the human mind:
(i.) an inability to distinguish between truths about masses
and truths about individuals; and (i.) a passion for ex-
plaining things; for possessing a formula for familiar pheno-
mena; in the case of heredity, for seeing below the line in
the diagram on p. 182.

Man has observed that on the whole Galton’s Law is
true of masses—though he has not expressed himself in these
words. Feature No. (i.) had led him to think that the truth
is of individuals, and has thus satisfied No. (ii.) and sup-
plied him with a brief formula, a simple picture of the way
in which characters are inherited—a picture of what is
below the line AB in the diagram.

Even if this is not a true history of the origin of the
Law of Contribution, the point about that Law which I
wish to enforce is that it is a physiological theory of heredity.
It is an attempt to account for the phenomena of heredity
by picturing the way in which the characters of an organism
are represented in the germ-cell which produces it. And
being a physiological Law, it is profoundly different from a
statistical one like Galton’s, which does not pretend to
account for anything, but is a generalisation about the
relation between the aggregates of adults of successive
generations.

In a word, a physiological Law deals with the individuals
of each generation on both sides of the line AB in the

181

An Introduction to a Biology

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182

An Introduction to a Biology

diagram ; a statistical one, with the generation as a whole
on the upper side only. Another way of marking the difier-
ence between physiological and statistical Laws of heredity
is to say that the former are explanatory while the latter
are descriptive. To which it will be immediately objected
that no Law ever explains anything. I am perfectly aware
of this, and of the fact, moreover, that no theory does; in
fact, that we cannot explain anything at all in nature;
that all that we can do is to describe. But at the same time
it cannot be denied that there is all the difference between
attempting to account for a phenomenon and contenting
oneself with describing it; and one is, I hold, perfectly
logical in making this attempt to explain, although one
knows that, however intimate a knowledge of causation one
has acquired, one has done no more than describe phenomena.
One great difference between these two things, the logical
attempt to explain, and satisfaction with mere description,
is that the method of the former is experiment and that of
the latter is observation. Another difference is that it
is only by attempting to account for things that we have
been enabled to get what knowledge we have of the causa-
tion of natural phenomena and so to obtain what control
we have of the operation of natural processes. Just be-
cause we know that explanation is after all only description,
it does not follow that we should abandon the attempt to
account for things.

We are now in a position to classify Laws of heredity
under these two headings :

Physiological. Statistical.
(a) Mendel’s Law. (a) Galton’s Law.
(b) The Law of Contribution. (6) Pearson’s Law.

Now inasmuch as of physiological Laws 6 has been shown
to be invalid, and of statistical ones a@ has been shown to
be less comprehensive than 0, the discussion of the mutual
relation of physiological to statistical Laws of heredity

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An Introduction to a Biology

resolves itself into a discussion of the relation of Mendel’s
Law to Pearson’s Law of Ancestral Inheritance.

(b) MenpE’s Law True or Units: PEARSON’s, OF
MASSES :

Discussing a little while ago with a friend the relation
of Mendelism to biometry, I suggested as the briefest possible
statement of the difference between the two that Mendelism
treated of units, and biometry of masses of units. My
friend replied: ‘‘ You speak of the animals and plants with
which you deal as breeding true to such and such a char-
acter. What do you mean by this statement? Are the
ofispring absolutely identical with their parents in respect
of the character under consideration? Jf they are not,
how like are they ; and how is the degree of this similarity
to be measured, except by biometric methods ? ”

I saw that there was truth in what he said, but I could
not see the relation which the idea in his mind bore to my
original idea, to which I still adhered, that Mendelism dealt
with the units, while biometry was concerned with masses.
Now I see that my inability to do so was due to the fact
that biometry meant to my friend that the only way to
measure the resemblance between parents and children is
the method of the correlation table ; in which he was quite
right; while biometry called up in my mind the Law of
Ancestral Inheritance, and especially the manner in which
data designed to establish that Law are collected and dealt
with ; such, for example, as in the case of one of the last
series of data from which such correlation coefficients have
been worked out—that of greyhounds. I had in my mind
the collective treatment in one correlation table of such
different characters as Black, Brindled, Fawn, White, and
Red ;! while he was thinking of the only method of measuring
the intensity of inheritance within a single such character
—say, Red. Now this, I believe, brings us to the heart

1 Barrington, etc., :05, p. 264.
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An Introduction to a Biology

of the matter. When I say that the Mendelian deals with
units and the biometrician with masses, I mean, not that
the former deals with a few and the latter with many, but
that the former first settles what character he is going to
treat as a unit and then only deals with it in large numbers
when he is sure that the component units of this number
are identical, their sameness having reference to such pro-
perties as can be discovered by mating them with their
like and with their unlike. It is just as necessary for the
Mendelian to have a large record of matings as the biometrician
to establish his generalisations. But though the Mendelian
might allow that the only method of measuring the simi-
larity between parents and offspring within a group (such
as the unit character Red) was that of the correlation table,
he would vehemently maintain that the biometric method
overstepped its limits when it included in such a table more
than one such category. What Bateson means when he
says that Mendel saw by sure penetration that masses must
be avoided, is that the biometric method oversteps its limits
when it does this.

The answer that I should now give to my friend is this:
“ T fully admit that the only method of measuring the degree
of resemblance between a generation and the one which pro-
duced it, within such a unit, is the biometric method; I
fully agree with the biometrician when he says that all
green peas are not alike in respect of their greenness because
all green peas are green, and that the biometric method is
the only one to measure their dissimilarity ; but I stoutly
maintain that when he puts green and yellow peas together
into a correlation table he has started on a path which will
not lead to a more intimate knowledge of heredity.”

Biometry furnishes the only means of actually measuring
the intensity of heredity within a unit ; Mendelism furnishes
the only means by which a fuller knowledge of the properties
of these units may be acquired.!

1 Exactly the same idea is expressed by Lotsy, :06, p. 143.
185

An Introduction to a Biology

It is sometimes easy to determine the extent of these
units, as in the case of discontinuous characters such as
purpleness and whiteness of flower in Pisum :1 it is often
difficult, as in the case of characters varying continuously
such as the weight of beans.?

Careful consideration of the table in my paper?
on the supposed antagonism of Mendelian to biometric
theories shows that the accuracy with which Mendelian
or Galtonian Law describes the facts of heredity depends
on the composition of the unit tested. There is nothing
a priory illogical in treating the sharply defined category
of dark-eye-and-coloured-coat, in mice, as a unit. Suppose
this is done: Galton’s Law fits the facts beautifully, while
Mendel’s is triumphantly refuted (by showing that the
amount of albino ancestry of a hybrid affects the percentage
of albinos produced by such hybrids mated inter se); to
which the Mendelian would make the following answer:
“Are you sure that your unit ‘ dark-eye-and-coloured-
coat’ is incapable of resolution into still simpler units? Are
you sure that you are not regarding as a simple thing that
which is really compound, just as the ‘ fixed alkalies’ were
regarded as elements until Davy 4 showed them to be com-
pounds ?° I can prove that you are; for by testing the
gametic constitution of the dark-eyed and coloured-coated
forms I can show that they are sharply distinguished into
heterozygous and homozygous forms. Now I claim to have
discovered what should really be treated as a unit, namely,

1 Fruwirth, :06, p. 141. 2 Johannsen, :03.

3 Darbishire, :05a, vide supra, p. 148. 4 Davy, ’08.

5 This illustration may at first sight appear not to be strictly parallel.
A chemist reading it would think that what was going to be shown was
that the unit “ dark-eye-and-coloured-coat ’? was resolvable into “‘ dark-
eye’ and “ coloured-coat,”’ whereas, of course, what is really going to be
Shown is that the units “‘ dark-eye ” and “ coloured-coat ”’ are of two quite
distinct kinds. The true parallel to my case is the idea of the element
before Davy’s time. Amongst the things that were classed as elements,
some really were undecomposable (cf. the homozygous forms), while others
—the alkalies—were decomposable (cf. the heterozygous),

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An Introduction to a Biology

that character which, like the elements of the chemist, can-
not. be split up into simpler characters. I do not pretend
that my formule of heredity describe the numerical results
obtained by jumbling a lot of my elemental units together,
any more than you pretend that the Law of Ancestral Heredity
describes the phenomena exhibited by my units when dealt
with separately.”

The point that I wish to bring home to the reader is that
the statement that Mendelism deals with units and biometry
with masses is not merely a brief summarising statement
which pleases the mind, but that it has an actual meaning
in relation to the facts; that is to say, that the limits of
these units are not set by the imagination, but are discovered
by experiment.

(c) EXAMPLES OF THE CONFUSION BETWEEN PHYSIOLOGICAL
AND STATISTICAL Laws

Having spoken this much on the difference between
physiological and statistical Laws of heredity, I propose
to consider a few cases where failure to perceive this differ-
ence has led to confusion. As I have already referred to
Castle’s case, I will finish with it before I proceed to others.
He says:1 “The foregoing results show very clearly that
albinism conforms in the mode of its inheritance to Mendel’s
law of heredity. The fact, however, must not be overlooked
that a somewhat different explanation of its inheritance (1)
has recently been given, based on Galton’s “law of ancestral
heredity.” I shall not at this time enter into a detailed
discussion of Galton’s hypothesis, which was an entirely
rational one in the form in which it was originally proposed (2);
and quite in harmony with the phenomena of gametogenesis (3)
as then interpreted. I have shown elsewhere? by a specific
test in the case of mice, based on the observations of von
Guaita, that Galton’s law fails to account for the observed
facts (4) concerning the inheritance of albinism, but that

1 Castle, :05, p. 16, 2 ibid., :03, p. 231.
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An Introduction to a Biology

Mendel’s law does this perfectly. Nevertheless Darbishire,
likewise dealing with albinism in mice, though admitting
that certain of his results are not in disagreement with
Mendel’s law, is inclined rather to interpret the phenomena
on some such hypothesis as that of Galton” (5).

The numerals refer to the words in italics preceding
them.

(1) This shows that Castle followed me in confusing Galton’s
Law with the Law of Contribution.

(2) Here we see that Castle has started on a right track :
he has perceived that Galton’s Law in the sense in
which I used it, meaning the Law of Contribution, is
not the same as that Law in its original form.

(3) And yet he thinks that in its original form it was in
harmony with the phenomena of gametogenesis as
then interpreted, whereas it seems to me that the chief
characteristic of a statistical Law is that it is inde-
pendent of any theory of gametogenesis whatsoever.

(4) Of course it does: because it does not attempt to. What
he means is that the Law of Contribution attempts
and fails: and this is quite true.

(5) Here again as in (2) we see light breaking in on the con-
fusion between Galton’s Law and the Law of Contri-
bution. Castle sees that the theory of heredity I
had in mind is not quite the same as Galton’s: I
have shown (p. 180) exactly how it differs from it.

I will now refer to a case in which the confusion between
Galton’s Law and that of Contribution is complete.

In 1904 I wrote :1 “I do not propose to discuss here the
difference (1) between Mendelian principles and the statistical
conception of inheritance (2), but to consider one part of
the hypothesis put forward by Mendel, which is at variance
with Galton’s theory(3). I refer to the phenomenon of
segregation. We have seen what Mendel says. But this
is flatly contradicted by the Galtonian generalisation (4),

1 Darbishire, :04b, p. 9.
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An Introduction to a Biology

according to which the greater number of generations a
given hybrid is from the first hybrid . . . the fewer pure
recessive and dominant forms is it likely to produce when
mated with another hybrid of its own generation.”

(1) For the very good reason that I did not then understand
it: as I do now.

(2), (3,) (4) If “‘ Law of Contribution ” is put in the place
of the terms 2, 3, and 4, this passage is quite true
As it stands, it is nonsense.

Perhaps, after all, the most complete example of this
confusion is to be found in Castle’s writings; it occurs in
his paper on Galton’s and Mendel’s Laws. He gives a Table!
to show the difference between the Mendelian and Galtonian
prediction of the number of albinos produced by crossing
Japanese waltzing mice with albinos, together with the
actual numbers that occurred in von Guaita’s well-known
experiment.?

I give the top two lines of the Table.

Mendel’s Law. | Observed Galton’s Law.
Generation. | Total Young.| Calculated No. No. of Calculated No.
of Whites. Whites, of Whites.

D. 28 0 0 14

Substitute Law of Contribution for Galton’s Law, and
the idea conveyed by the Table is sensible and true.

I will refer to one more passage in which Galton’s Law
is used in the sense of the Law of Contribution: ‘“ Nach
Galtons Theorie muss jede Gamete, welche von einem In-
dividuum produziert wird, imstande sein, alle Merkmale der
Sippe, welcher es angehdrt, auf die Nachkommen zu iiber-
tragen; es ist unmdglich, dass gewisse Gameten fiir immer
von der Ubertragung gewisser Merkmale ausgeschlossen

1 Castle, :03, p. 231. 2 Quaita, ’98 :00.
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An Introduction to a Biology

werden.” 1 Here ‘“‘ Galtons Theorie” is made to refer not
merely to the individual but to the gamete borne by it, and
the expression as here used means nothing more nor less
than the Law of Contribution. It is true that Galton him-
self tentatively suggested,? when he formulated his Law,
that it might become applicable to the individual.* But
his Law, as it stands, is a statistical Law true of masses of
units; and when a physiological theory of heredity, as in
the above quotation, is spoken of as “Galtons Theorie,”
it is high time that a new term is invented to describe it.
I have proposed the ‘“‘ Law of Contribution.”

Nothing could be more fatal to profitableness of dis-
cussion than that two such profoundly different things as
Galton’s Law and the Law of Contribution should go by
the same name.

So long as physiological are not clearly distinguished
from statistical Laws of heredity, biologists will continue
to slide from meaning a physiological to meaning a statis-
tical one; and the transition will be unconscious because
the term by which they denote these two different things
is the same—namely, Galton’s Law. Progress in the study
of heredity will be slow as long as this confusion prevails.
For so long as it prevails we shall continue to hear the in-
sensate statement that ancestry makes a difference. Of course
it makes a difference—in the mass; which it is the business
of the biometrician to measure and of the Mendelian to
account for. Anyone who proclaims that his results prove
that ancestry makes a difference, without making it clear
whether he has in mind a physiological or a statistical theory,
is drawing a conclusion which is meaningless. For his con-
clusion to have a meaning, he must make this clear. If he
is referring to the former, he is declaring for the Law of
Contribution; if to the latter, for the Law of Ancestral
Inheritance.

When the Mendelian says that ancestry does not make
1 Lotsy, :06, p. 152. * See Appendix A, p. 196 infra. * Galton, ’97, p. 403.

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An Introduction to a Biology

a difference, he is not denying the validity of the Law of
Ancestral Inheritance but the Law of Diminishing Individual
Contribution. At least, I think this is the correct attitude.

And I cannot bring myself to agree with Bateson when
he says that facts once describable by Mendel’s Law are
permanently removed from the operation [sc] of the Law
of Ancestral Inheritance, unless all that he means by this
statement is that when we have gained this deeper know-
ledge of certain hereditary phenomena their further treat-
ment by the method of the correlation table will not increase
our knowledge of them. I should like to think that this is.
all he means ;’ but his writings prevent me, for he imputes
to upholders of Pearson’s Law belief in the Law of Contri-
bution ;1 yet on the next page he shows that he has not
confused the two, bysaying that the Lawof Ancestral Heredity
‘* does not directly attempt to give any account of the distribution
of the heritage among the gametes of any one individual.” I
do not know whether Bateson sti holds that Mendel’s Law
is antagonistic to the Law of Ancestral Inheritance as well
as to the Law of Contribution. If he does, I do not under-
stand on what grounds. Pearson has investigated the re-
lation between the two, and concludes “that in the theory
of the pure gamete there is nothing in essential opposition
to the broad features of linear regression, skew distribution,
the geometric law of ancestral correlation, etc., of the bio-
metric description of inheritance in populations.” ? And
no flaws in the argument of my paper on the supposed an-
tagonism of Mendelian to biometric theories have been
pointed out to me; in fact, Correns* and Giard4 have
expressed their agreement with it.

I feel most strongly that so long as we confuse physio-
logical with statistical Laws of heredity we are wandering
in the dark: we cannot know in what direction our studies
are leading us, whether we are establishing correlations

1 Bateson, :02, p. 21, second half. 2 Pearson, :03b, p. 86.
3 Correns, :05, p. 43. 4 Giard, :05, p. 22.
1gI

An Introduction to a Biology

among the leaves or are digging among the roots. It may
or may not be that what we learn by the former method is
all that we shall ever know, and that we shall find nothing
by our digging ; but be this as it may, I hold that it is essen-
tial to progress in discovery, no less than to clearness of
thought, that we should know which of the two we are
doing.

(d) DescripTION oF A MetTuop oF DEALING WITH THE
MATERIAL OF A BREEDING EXPERIMENT IN SUCH A WAY
THAT THE DATA OBTAINED MAY BE USED TO TEST THE
VALIDITY BOTH OF MENDEL’S AND PraArRson’s LAw

When I had finished my last paper on my hybridisation
experiment with mice*® I was still of the opinion that Men-
delian and biometric Laws of heredity were mutually ex
clusive, and that if I could discover which of the two was
true, I should be making a forward step in our knowledge
of heredity. I therefore devised an experiment which was
destined to settle this question ; and wasted a year in carry-
ing 1t out. As soon as I discovered the true relation of
the two Laws I devised a method of dealing with my ex-
periment, of such a kind that the results could be utilised
by the Mendelian or the biometrician to test his own par-
ticular Law; for the stringency with which the mice were
selected in the previous part of the experiment rendered
the results useless for anyone who wished to test the Law
of Ancestral Inheritance by them.

What was wanted was some device to ensure the random
mating of the mice, and at the same time to ensure the possi-
bility of tracing all the ancestors and all the offspring; in
fact, all the relations of every degree of every individual
mouse; the second condition had been fulfilled in the pre-
vious part of my experiment, but the first had not, because
the different kinds of mice had been rigidly selected.

The method by which I mated the mice at random was

8 Darbishire, :04a,
192

An Introduction to a Biology

very simple. I wrote the catalogue-name of each mouse
on a counter, then I put the counters representing female
mice into one hat and those representing males into another :
all that remained to be done was to draw out at random
a counter from the ‘“‘ female” hat and similarly one from
the “male” hat, and to mate the actual mice represented
by these counters. As I have said, this method enables one
to test the Law of Ancestral Inheritance and Mendel’s Law.
As far as the first is concerned, it is the most perfect con-
ceivable ; but for the second it is clumsy and involves un-
necessary labour, because what is aimed at in a Mendelian
experiment is the discovery of the properties of character-
units, as far as they can be discovered by determining the
specific results of their union with similar and dissimilar
character-units. Now some particular combination of char-
acters may turn up very seldom by the method of random
union; and if one wishes to discover the result of such a
combination one has to wait until the drawings from the
hat give it. One is in the position of an observer, and if
one wishes to attain the knowledge of the result of such a
combination quickly and in large numbers, the random
mating and the counters must be discarded and one must
deal experimentally with the material, isolating the indivi-
duals the properties of whose character-units one wishes to
determine.

I had planned at the beginning of last year (1905) to
do the same experiment with peas by mating at random
peas with green round seeds (Eclipse) with peas with yellow
wrinkled seeds (British Queen), and with each other; and
had already sown the seed, when it occurred to me that
I need not have done so. We know! the result of crossing
a yellow wrinkled with a green round pea, and of their mating
inter se: so that all that is necessary is to start with a
hat containing equal numbers of yellow and green counters
representing pistil parents, and a hat with similar contents

1 Hurst, :O4
N 193

An Introduction to a Biology

representing pollen parents, and to mate the contents at
random, the result of each of the three possible unions,
gX9,9 XY, y X y, being known by previous experiment.
And the result of the matings of the various kinds of off-
spring can be predicted from the knowledge which we have
of their gametic constitutions. Thus, for example, in F%,,
a yellow resulting from the union yellow x yellow! will
produce only yellow when mated with green; but a second
yellow (indistinguishable by outwardly observable features
from the first) produced by the union yellow x green will
produce half yellows and half greens when mated with
green; while a green of what ancestry soever will always
produce green when mated with green.

Ea hypothesi Mendeliano it is possible to predict the
result of these unions for however many generations
the experiment is continued, because in its simple
form that Law states that the result, for example, of
DR xDR will always be the same whether the mating
of hybrids takes place in F,or Fy). The Mendelian hypo-
thesis in this simple form may or may not be right; and
I, for one, think that it is not. But this does not damage
my argument. My point is that you can determine the
properties of the hybrids in different generations—supposing
that they are not the same in all; and having acquired
this knowledge you can then return to the counters and see
whether the result of mating your material at random can
be described by the Law of Ancestral Inheritance. What
I want to make clear is that the knowledge of heredity
acquired by the Mendelian is deeper, is nearer the pheno-
mena themselves, than is that acquired by the biometrician,
and is such that the latter, if he is inclined, can use it as
material with which to test the Law of Ancestral Inheritance
without the labour of conducting a breeding experiment.

Having devised my method, therefore, I discovered that
it was unnecessary to use it. So I abandoned it, in the case

1 These colours refer to the gametes.

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An Introduction to a Biology

both of the mice and of the peas. I am now investigating
the properties of the various kinds of individuals in various
generations in both cases, accumulating information (of a
physiological nature) which will be available to the bio-
metrician for use in testing the Law of Ancestral Inheritance.

(e) Way po WHITE SHEEP EAT MORE THAN BLACK

OnzEs ?
I was asked the other day this well-known riddle, and
as I had forgotten the answer I was told it: “ Because

there are more of them.”

The supplying of the answer never provokes a laugh,
yet the relation between it and the question 1s full of interest.
Let us discuss it. When you ask the riddle you do not say
that you are not referring to individual white and black
sheep, but the man of whom the riddle is asked invariably
thinks that you are. In attempting to answer it, the ideas
that rush through his mind may either take the form of
seeking for some pun on the words, or perhaps for some
humorous quotation in which they appear; and so forth:
or, aS usually happens, he thinks that, as a matter of
fact, a white individual does eat more than a black, and
(if he is a biologist) he may be trying to think of some physio-
logical explanation of the fact, in connection possibly with
the well-established relation between pigmentation and
the getting rid of waste products.

In the answer he is told that the amount eaten by the
sum-total of white sheep as compared with that eaten by
the sum-total of black sheep is the subject under discussion ;
and not any peculiarities of ingestion, digestion, or egestion
associated with whiteness as compared with blackness.

If the antithesis between truths about masses and truths
about individuals which constitutes the point in this riddle
were more widely and more clearly perceived than it is to-day,
there would no longer be that confusion in the minds of
most biologists which prevents them seeing the profound

195

An Introduction to a Biology

difference that exists between a physiological Law like
Mendel’s, which is true of units, and a statistical one like
the Law of Ancestral Inheritance, which is true of masses.
All intending students of heredity should be asked this riddle ;
and if they cannot detect the fallacy in it they should be
declared unfit for their intended task.

The similarity between the impression made on the
mind by asking the question and Mendelism, and that
between the idea conveyed by the answer and the Law
of Ancestral Inheritance does not lie only in the fact
that while the question and Mendelism deal with indi-
viduals, the answer and the Law of Ancestral Inheritance
refer to masses. The idea implied in the question is lke
Mendelism, because it suggests what Mendelism effects,
the discovery of a hitherto unsuspected order in familiar
phenomena; while the truth conveyed in the answer is
like the biometric treatment of heredity, because it is the
accurate statement of a relationship that you already know
to exist. Everyone knows that the sum-total of children
are more or less like the sum-total of their parents; the
biometrician accurately measures the degree of this resem-
blance.

The answer you expect is physiological. The answer
you get is statistical.

APPENDIX A to p. Igo

It is interesting to inquire what Galton himself said,
when he formulated his Law, on the subject of its applicability
to individual cases. He said (’97, p. 403): “It should be
noted that nothing in this statistical law contradicts the
generally accepted view that the chief, if not the sole, line
of descent runs from germ to germ and not from person to
person. The person may be accepted on the whole as a
fair representative of the germ, and, being so, the statistical
laws which apply to the persons would apply to the germs
also, though with less precision in individual cases. Now
this law is strictly consonant with the observed binary sub-

196

An Introduction to a Biology

divisions of the germ-cells, and the concomitant extrusion
and loss of one-half of the several contributions from each of
the two parents to the germ-cell of the offspring.” Mark
his words, “. . . though with less precision in individual
cases ’’—the italics are mine. If one were referring to
Galton’s Law (in the form in which it is true of masses only)
one would say, “. . . without applying at all to individual
cases”?; and if to the Law of Contribution, “. . . with
absolute precision to individual cases.”” But I may be inter-
preting this wrongly, for the “less” may refer not to the
difference between population and individual, but to the
difference between person and germ. And, in fact, I think the.
following quotation from the previous page (’97, p. 402) justifies
us in concluding that Galton conceived his Law as being
true solely of masses without being true of the component
individuals. ‘‘The neglect of individual prepotencies is
justified in a law that avowedly relates to average results...”
At any rate, it simplifies matters very much to consider
that Galton’s Law as he formulated it is true of masses only,
and not of their component units; for if we do not, we
have to keep three laws distinct in our minds:

1. Galton’s Law as he formulated it: true of masses, but
also, though with less precision, of individuals.
Statistical and Physiological.

2. Galton’s Law: true of masses only. Statistical.

3. The Law of Contribution: true of units. Physio-
logical.

APPENDIX B to p. 171

There is nothing, of course, in the word “ contribute ”
to definitely signify that the thing which is contributed is
the same as that which contributes: in fact, in the every-
day usage of the term this is hardly ever the case. But it
is reasonable to hold that Galton’s Law is the generalisation
that like contributes like and not unlike; and it is certain
that Galton himself meant this, as the last words of his
illustration of particulate inheritance readily show: “. . . each
piece of the new structure is derived from a corresponding
piece of some older one, as a lintel derived from a lintel,
a column from a column, a piece of wall from a piece of
wall.” (89, p. 8.)

197

An Introduction to a Biology

APPENDIX C to 4 (b) pp. 184-7

There is an apparent paradox, in the ideas just expressed,
about which I think it is necessary to say a few words, in
case the reader should detect it himself and think that it
had not occurred to me.

I have said that biometry deals with masses and Men-
delism with units; but I have also said that the biometrician
exceeds his proper limits when he goes beyond the boundary
of a unit, while the Mendelian is concerned with the mutual
properties of numerous units; in other words, the sphere
of the biometrician is within the unit, while that of the
Mendelian is outside it.

The fundamental idea on which the Law of Ancestral
Inheritance is based is that set forth in the quotation from
Pearson!; it is that a knowledge of the characters of the
parents does not enable us to predict the character of the
offspring in individual cases.

The fundamental idea in Mendelian theory is that the
ascertainable gametic characters of the parents do enable
us to predict the character of the offspring in individual cases.

How are these two diametrically opposite ideas about
heredity to be reconciled ?. The answer which most naturally
suggests itself is that the biometrician happens to have dealt
with cases about which it was impossible to predict in in-
dividual cases; while the Mendelian happens to have dealt
with cases in which prediction was possible. This answer pre-
supposes the existence of two sets of phenomena in heredity,
those about which it is possible to predict, and those about
which it is not. Now let us grant for the moment that the
Mendelian theory (which I think by no means proven yet)
that the characters of an organism consist of a number of
separate character-units, is true. What relation, if any, do
the two sets of hereditary phenomena—the predicable and
the non-predicable—bear to these units? Just this. The
non-predicable phenomenon is the incomplete correlation
between the degree in which any character z is exhibited
by a parent, in a single case, and the degree in which that
same character is exhibited in its child. The predicable
phenomenon is the result of the union of z with z, or of
wz with y.

1 Vide supra, p. 169
198

An Introduction to a Biology

Chemistry furnishes a parallel. The chemist cannot pre-
dict the rate at which any given atom in a litre of oxygen
is travelling; he can only deal with “ statistics of average
conduct”’; but he can predict the result of passing an
electric spark in a vessel containing oxygen and hydrogen.
Yet he who deals with the properties of the elements may be
said to deal with units, and he who deals with the component
atoms—and one can only deal with them in large numbers—
may be said to deal with masses.

It is true that the biometrician possesses the only means
of measuring the “ intensity of heredity ” in a non-predicable
case, but it seems to me that to extend the application of:
these means to predicable cases is fallacious. If the true
function of the biometrician is to give us statistics of average
conduct where we cannot predict individual conduct, it seems
to me that to deal by the biometric method with cases where
we can is not only unprofitable, but likely to lead men to
think that where there are two methods dealing with the
same material, of which the one can predict while the other
cannot, the latter is fallacious. Whereas if the biometrician
confined himself to the non-predicable and the Mendelian
to the predicable, the general conclusion would be that each
had his proper sphere—which indeed, in my belief, he has.
I do not set forth these views in any spirit of dogmatic
certainty ; and nothing could please me less than that they
should go unchallenged by anyone who believes me to be
mistaken.

LITERATURE REFERRED TO IN THE TEXT

’°08. Davy, Humpury. ‘‘ On some New Phenomena of che-
mical Changes produced by Electricity, particularly
the Decomposition of the Fixed Alkalies, and the
Exhibition of the New Substances which constitute
their Bases; and on the general Nature of alkaline
Bodies.” Phil. Trans., Vol. 98, p. 1.

’°89. Gatton, Francis. ‘‘ Natural Inheritance.” Macmillan
and Co.

°95. CouTAGNE, G. ‘‘ Recherches sur le Polymorphisme des
Mollusques de France.” Lyon.

97. Gatton, Francis. ‘‘ The Average Contribution of each

199

An Introduction to a Biology

Several Ancestor to the Total Heritage of the Off-
spring.” Proc. Roy. Soc., Vol. 61, pp. 401-138.

°98. Guarra, G. von. ‘“‘ Versuche mit Kreuzungen von
verschiedenen Rassen der Hausmaus.” Ber. d. naturf.
Gesell. Freiburg, Vol. 10, p. 317.

:00. Guarra, G. von. 2“ Mittheilung, etc., abid., Vol. 11,
p. 131.

:02. Batrson, W. ‘“‘ Mendel’s Principles of Heredity.” Uni-
versity Press, Cambridge.

:03. CastLE, W. E. ‘‘ The Laws of Heredity of Galton and
Mendel, and some Laws governing Race Improvement
by Selection.” Proc. Amer. Acad. Arts and Sct., Vol.
39, No. 8.

03. JoHannseN, W. “ Ueber Erblichkeit in Populationen
und in reinen Linien.” Jena. Verlag von Gustav
Fischer.

03a. Pearson, Karu. ‘‘ The Law of Ancestral Heredity.”
Biometrika, Vol. 2, p. 211.

:03b. Pearson, Karu. ‘‘ Mathematical Contributions to the
Theory of Evolution. XII. On a Generalised Theory
of Alternative Inheritance; with special Reference to
Mendel’s Laws.” Phil. Trans., Ser. A., Vol, 203, pp.
53-86.

04a. DarpisutrE, A. D. “On the Result of Crossing
Japanese Waltzing with Albino Mice.” Biometrika,
Vol. 3, p. 1.

:04b. DarpisuirE, A. D. ‘‘On the Bearing of Mendelian
Principles of Heredity on current Theories of the
Origin of Species.” Manchester Memoirs, Vol. 48, No.
24, 19 pp.

04. Hurst, C. C. ‘‘ Experiments in the Heredity of Peas.”
Journ. R. Hort. Soc., Vol. 28, pp. 483-94.

:04. Lance, Arnotp. ‘‘ Ueber Vorversuche zu Untersuch-
ungen iiber die Varietatenbildungen von Helix horten-
sis Miller und Heliz nemoralis L.” Festschrift zum
siebzigsten Geburtstage von Ernst Haeckel, p. 439. Jena.

:04. Pearson, Karu. ‘‘ On the Laws of Inheritance in Man.”
II. ““On the Inheritance of the Mental and Moral
Characters in Man, and its Comparison with the In-
heritance of the Physical Characters.” Biometrika,
Vol. 3, p. 131.

200

*

An Introduction to a Biology

705. Barrineton, Amy; Ler, ALICE; and PEARSON, KARL.
‘* On the Inheritance of Coat-Colour in the Greyhound.”
Biometrika, Vol. 3, p. 245.

705. Castte, W.E. “ Heredity of Coat Characters in Guinea-
Pigs and Rabbits.” Pub. by the Carnegie Institution
of Washington.

05. Correns, C. “ Uber Vererbungsgesetze.” Berlin. Ver-
lag von Gebriider Borntraeger.

05a. Darpisutre, A. D. “On the Supposed Antagonism of
Mendelian to Biometric Theories of Heredity.” Man-
chester Memoirs, Vol. 49, No. 6, 19 pp. |

:05b. DarsisutreE, A. D. ‘“ Professor Lang’s Breeding Ex-
periments with Helix hortensis and H. nemoralis ; an
Abstract and Review.” Journ. of Conchology, Vol. 11,
p. 193.

705. Fruwirta, C. “ Die Ziichtung der landwirthschaftlichen
Kulturpflanzen,” Vol. 1. “Allgemeine Ziichtungs-
lehre,” 2° Aufl.

05. Grarp, A. “L’Evolution des Sciences Biologiques.”
Congrés de l’ Association Francaise pour 0 Avancement
des Sciences. Cherbourg.

:05. Punnett, R.C. ‘‘ Mendelism.”? Macmillan and Bowes,
Cambridge.

:06. Fruwirtu, C. “Die Ziichtung der landwirthschaft-
lichen Kulturpflanzen,” Vol. 3.

06. Lanc, Arnotp. ‘‘ Uber die Mendelschen Gesetze, Art
—und Varietatenbildung, Mutation und Variation,
insbesondere bei unsern Hain—und Gartenschnecken.”’
Verhandl. der Schweiz. Naturf. Gesell.

:06. Lotsy, J. P. ‘‘ Vorlesungen iiber Deszendenztheorien
mit besonderer Beriicksichtigung der botanischen Seite
der Frage ”’ (especially Lectures 8, 9, 10 and 11). Jena.
Gustav Fischer.

:06. ScuustER, E. ‘On Hereditary Deafness: A Discus-
sion of the Data collected by Dr. E. A. Fay in America.”
Biometrika, Vol. 4, p. 465.

:06. Wetpon, W. F. R. ‘Inheritance in Animals and
Plants,” pp. 81-109, in “ Lectures on the Method of
Science.” Edited by T. B. Strong, Clarendon Press,
Oxford.

201

An Introduction to a Biology

Further List of Articles, etc. (dealing with Heredity from the
Statistical and Physiological Aspects), which have ap-
peared during and since 1904, and not included in the list
at the end of my paper :04b in the preceding list.1

03. YuLe, G. Upny. ‘“‘ Professor Johannsen’s Experiments
in Heredity: A Review.” New Phytologist, Vol. 2,
No. 10. [This paper should have been in the list at
the end of my first paper to this Society. Darbishire,
:04b.]

704. ALLEN, G. M. “The Heredity of Coat Color in Mice.”
Proc. Amer. Acad. Arts and Sct., Vol. 40, No. 2.

:04. Bateson, W., SAUNDERS, E. R., and Punnett, R. C.
“ Reports to the Evolution Committee of the Royal
Society,’ Report 2.

:04a. Batrson, W. “ Presidential Address to Section D.”
Brit. Assoc. Reports, Cambridge, 1904, p. 574.

:046. Bateson, W. “ Albinism in Sicily: A Correction.”
Biometrika, Vol. 3, p. 471.

:04. Birren, R.H. ‘“ An ‘ Intermediate ’ Hybrid in Wheat.”
Brit. Assoc. Reports, Cambridge, 1904, p. 593.

:04a. CornreNns, C. “ Experimentelle Untersuchungen iiber
die Gynodioecie.” Ber. Deutsch. Bot. Gesell., Vol. 22,
Part 8, p. 506.

:04b. CorrEeNs, C. “ Ein typisch spaltender Bastard zwischen
einer einjahrigen und einer zweijaihrigen Sippe des
Hyoscyamus niger.” Ber. Deutsch. Bot. Gesell., Vol. 22,
Part 8, p. 517.

:04. Cufnot, L. ‘“‘ Un Paradoxe héréditaire chez les Souris.
Réunion biologique de Nancy, p. 1050, séance du 13 Juin.

04. Darsisuire, A.D. “On the Result of Crossing Japanese
Waltzing with Albino Mice.” Brit. Assoc. Reports,
Cambridge, 1904, p. 591.

:04. Doncaster, L. ‘“‘ On the Inheritance of Tortoiseshell
and Related Colours in Cats.” Proc. Cambridge Philos.
Soc., Vol. 13, Part 1.

704. Durnam, F.M. “On the Presence of Tyrosinases in the
Skins of some Pigmented Vertebrates.” Proc. Roy.
Soc., Vol. 74, p. 310.

04a. Hacker, V. “Uber die neuefen Ergebnisse der Bas-
tardlehre, ihre zellengeschichtliche Bedeutung und ihre

1 Vide supra, p. 139
202

An Introduction to a Biology

Bedeutung fiir die praktische Tierzucht.” Arch. f.
Rassen- und Gesellschafts-Biologie, Jahrg. 1, Part 3.

7046. Hacker, V. “ Bastardierung und Geschlechtszellen-

bildung.” Zool. Jahrb., Suppl. 7, Festschr. f. Weismann.

:04a. Hurst, C. C. ‘‘ Mendel’s Discoveries in Heredity.”

Trans. Leicester Int. and Phil. Soc., Vol. 8, Part 2.
[Contains a useful list of references. |

:04b. Hurst, C. C. ‘‘ Experiments on Heredity in Rabbits.”

204,

204.

704,

704.

204.

204,

204,

704.

204,

704.

704.

204,

704,

Brit. Assoc. Reports, Cambridge, 1904, p. 592.

Le Danrtec, FEé.rx. “Les Influences ancestrales.”
Ernest Flammarion. Paris.

Lock, R. H. ‘“ Experiments on the Behaviour of Dif-
ferentiating Colour-characters in Maize.” Brit. Assoc.
Reports, Cambridge, 1904, p. 593.

Moenxuousse, W. T. J. “‘ The Development of Hybrids.”
Amer. Journ. of Anat., Vol. 3.

Noorpuign, C. L. W. “ Over Erfelijkheid en Verander-
ing der Kleuren.” Album der Natuur, August.

Pearson, Karu. “‘ Note on Mr. Punnett’s Section on the
Inheritance of Meristic Characters.” Biometrika, Vol.
3, p. 363.

PETRUNKEWITSCH, A. ‘“‘Gedanken iiber Vererbung.”
Freiburgi. Br. Speyer and Kaerner.

PunnetrT, R. C. “‘ Merism and Sex in ‘ Spinax Niger.”
Biometrika, Vol. 3, p. 313.

Raynor, G. H., the Rev., and Doncaster, L. “ Note
on Experiments on Heredity and Sex-determination
in Abraxas grossulariata.” Brit. Assoc. Reports, Cam-
bridge, 1904, p. 594.

RosENBERG, C. “‘ Uber die Tetradenteilung eines Dro-
sera-Bastardes.” Ber. Deutsch. Bot. Gesell., Vol. 22,
Part 1, p. 47.

SaunpErs, E. R. “Heredity in Stocks.” Brit. Assoc.
Reports, Cambridge, 1904, p. 590.

SrapLes-BrowneE, R. “ Experiments on Heredity in
Web-footed Pigeon.” Brit, Assoc. Reports, Cambridge,
1904, p. 595.

TscHERMAK, EK. “ Weitere Kreuzungsstudien an Erbsen,
Levkojen und Bohnen.” Zeittschr. f. d. landw. Versuchs-
wesen in Oest, 1904.

Wo .tTerstTorFF, W. “Triton Blasii und die Men-

203

704,

205.

:05.

‘05.

“OD;

5.

:05.

‘06.

it; ia

An Introduction to a Biology

del’schen Regeln.” Comptes rendus du 6° Congrés inter-
national de Zoologie, Session de Berne.

Wo.rterstorFr, W. “ Triton blasw de Isle, ein Kreu-
zungsprodukt zwischen Triton marmoratus und Tr.
cristatus.” Zool. Anz., Vol. 28, Sept.

Bateson, W., and Punnett, R.C. “A Suggestion as
to the Nature of ‘ Walnut’ Comb in Fowls.” Proc.
Cambridge Philos. Soc., Vol. 3, Pt. 3, p. 165.

Batrson, W., and Grecory, R. P. “ On the Inherit-
ance of Heterostylism in Primula.” Proc. Roy. Soc., B.,
Vol. 76, p. 581.

Bateson, W., SAuNDERS, HE. R. and Punnett, R. C.
‘Further Experiments on Inheritance in Sweet Peas
and Stocks: Preliminary Account.” Proc. Roy. Soc.,
B., Vol. 77, p. 236.

CastLtE, W. E. “ Recent Discoveries in Heredity
and their Bearing on Animal Breeding.” Pop. Sev.
Monthly, July.

Correns, C. An edition of “ Gregor Mendel’s Briefe an
Carl Nageli.” Abh. d. math.-phys. Kl. d. Kén. Sdchs.
Gesell. d. Wissensch., Vol. 29, No. 3.

Cutnot, L. ‘ Les Races pures et leurs Combinaisons
chez les Souris” (4"° Note). Arch. de Zool. eap. et gén.
[4], Vol. 3, Notes et Revue, No. 7, p. cxxil.

Doncaster, L. ‘‘ On the Inheritance of Coat-Colour in
Rats.” Proc. Cambridge Philos. Soc., Vol. 13, Part 4,
p. 215.

. Gatippe, V. “ L’Hérédité des Stigmates de Dégénéres-

cence et les Familles souveraines.” Paris. Masson et
Of,

. Hatscuex, B. “ Hypothése der organischen Vererbung.”

Leipzig. W. Engelmann.

. Hertwic, Oscar. “Ergebnisse und Probleme der

Zeugungs- und Vererbungslehre.” Jena. Gustav
Fischer.

. Hurst, C. C. “ Experimental Studies on Heredity in

Rabbits.” Journ. Linn. Soc.—Zoology, Vol. 29, p. 283.

. FaraBer, W. C. “Inheritance of Digital Malforma-

tions in Man.” Papers of the Peabody Mus. of Amer.
Archeol. and Ethnol., Harvard University, Vol. 3, No. 3.

. Farmer, J. B., and Moors, J. E. 8. ‘‘ On the Maiotic

204

at)

ku
‘ " ’

An Introduction to a Biology

Phase (Reduction Divisions) in Animals and Plants.”
Quart. Journ. Micr. Sci., Vol. 48, Part 2.

705. Lock, R.H. “‘ Studies in Plant Breeding in the Tropics.”
Annals Roy. Bot. Gard., Peradeniya; Vol. 2, Part 3,
p. 357.

705. MacDoveat, D. T. (assisted by Vain, A. M., SHULL,
G. H., and Smatt, J. M.). “Mutants and Hybrids
of the Oenotheras.” Pub. by the Carnegie Inst. of
Washington.

:05a. Morean, T. H. “The Assumed Purity of the Germ
Cells in Mendelian Results.” Science, N.S., Vol. 22,
pp. 877-79.

705d. Morean, T. H. “ Ziegler’s Theory of Sex Determina-
tion, and an Alternative Point of View.” Science,
N.S8., Vol. 23, No. 573, pp. 839-41.

:05. Noorpuisn, C. L. W. ‘Die Farben- und Gestalts-
Kanarien.” Magdeburg, Creutz’sche Verlagsbuch-
handlung.

05. Scuuster, H. H. J. “ Results of Crossing Grey (House)
Mice with Albinos.” Biometrika, Vol. 4, p. 1.

05. STRASBURGER, Epuarp. “Die stofflichen Grundlagen
der Vererbung in organischen Reich.” Gustav Fischer.
Jena.

705. Yute, J. Upny. “On the Influence of Bias and of
Personal Equation in Statistics of Ill-defined Quali-
ties: An Experimental Study.” Proc. Roy. Soc., A.,
Vol. 77, p. 337.

05. ZIEGLER, H. EH. “ Die Vererbungslehre in der Biologie.”
Gustav Fischer. Jena.

:06. Barrineton, A., and Pearson, K. “ On the Inheritance
of Coat-Colour in Cattle. Part I. Shorthorn Crosses
and Pure Shorthorns.” Biometrika, Vol. 4, p. 427.

706. Barzson, W. “ Albinism in Sicily.” Biometrika, Vol. 4,
p. 231.

:06. Davizs, C. J. “Horns in Polled Cattle; a Possible
Explanation.” The Estate Magazine for March, p. 99
[a popular article].

06. GALTON, Francis, and ScuusTEr, Epaar. “ Noteworthy
Families (Modern Science).” London. John Murray.

706. Hermper, Karu. “ Vererbung und Chromosomen.” Gus-
tav Fischer. Jena.

205

A } .
ae bie, ts
?

sa

An Introduction to a Biology

:06. Hewitt, C. G. ‘“ The Cytological Aspect of Partheno-
genesis in Insects.” Manchester Memovrs, Vol. 50,
No. 6, 40 pp., 2 pls. [Gives a very full list of papers
bearing on the subject of parthenogenetic inheritance. ]

06a. Hurst, C.C. ‘“* Notes on the Proceedings of the Inter-
national Conference on Plant Breeding and Hybridisa-
tion, 1902.” Journ. R. Hort. Soc., Vol. 29, Part 4.

:06b. Hurst, C. C. ‘‘ On the Inheritance of Coat-Colour in
Horses.” Proc. Roy. Soc., B., Vol. 77, p. 388.

:06. Prarson, K., and others. ‘‘ Co-operative Investigations
on Plants.” “III. On Inheritance in the Shirley
Poppy.” Second Memoir. Biometrika, Vol. 4, p. 394.

:06. Rem, G. ArncHpaLt. ‘On Mendel’s Laws, and the
Mutation Theory of Evolution,” being Appendix B to
the 2nd Ed. of his “ Principles of Heredity.” London.
Chapman and Hall.

706. SatEEBY, C.W. “Heredity.” London. T.C. and E. C.
Jack.

06. ScuimKEwitscu, W. “Die Mutationslehre und die
Zukunft der Menschheit.” Biol. Centralbl., Vol. 26.

.06. StapLEs-BrowneE, R. “ Note on Heredity in Pigeons.”
Proc. Zool. Soc., 1905, Vol. 2.

06. Witson, E. B. ‘‘ Mendelian Inheritance and the Purity
of the Gametes.” Science, N.S., Vol. 23, No. 577, pp.
112-3.

06. Woops, F. A. ‘‘ Mental and Moral Heredity in Royalty.”
New York. Henry Holt and Co.

06. Yue, G. Upny. “On a Property which holds good for
all Groupings of a Normal Distribution of Frequency
for Two Variables, with Applications to the Study of
Contingency-Tables for the Inheritance of Unmeasured
Qualities.” Proc. Roy. Soc., A., Vol. 77, p. 324.

206

VI

Recent Advances in Animal Breeding and their
Bearing on our Knowledge of Heredity

(Reprinted from the Report of the Royal Horticultural Society's
Third International Conference on Genetics, 1906, by
permission of the President and Council)

Curious results are obtained by crossing albino with the
so-called Japanese waltzing mice. It is perhaps not neces-
sary to say that an albino mouse is one with an absolutely
white coat and with pink eyes, the pink colour in them being
due, not to a special pigment, but to the colour of the blood
in the vessels at the back of the eye.

The colour of the waltzing mice used in this experiment
is best described by saying that were it not for a patch of
fawn on the shoulders, and sometimes on the rump, they
would be albinos. Their curious movements, inaccurately
denoted by the term “ waltzing,’ are not likely to be
forgotten by those who have seen them. The animals
appear to have no control of the movements of their heads,
nor of the direction in which they themselves proceed ;
and when they are awake, they spend most of their time in
twirling round and round, apparently mad, in a very small
circle.

When these two are mated the result is a mouse hardly
distinguishable from our common house mouse (when the
albino parent is pure bred).

The hybrid, therefore, has a grey-brown coat and coal-
black eyes.

207

.
- i) :
,.

An Introduction to a Biology

We start with a pink-eyed mouse with a colourless coat
(which we may denote for brevity’s sake by the formula
OO), the albino, and mate it with a mouse which is also
pink-eyed but has a partially-coloured coat (which we may
call OC), and get as a result a black-eyed mouse with a
fully-coloured coat (which we may call CC). So much for
the nature of the hybrids as far as colour is concerned. Now
for their progression. The hybrids never waltz. This is true
of the hundreds that I have raised.’ |

Let us now consider the result of mating these hybrids
together. First with regard to colour. The offspring pro-
duced by the union of these hybrids fall into the three cate-
gories OO, OC, and CC, in the proportions 25, 25, and 50
per cent. respectively. That is to say, in point of colour,
on the average one mouse in every four is like its albino
grandparent; one in every four like its waltzing grand-
parent ; and two in every four like their parents the hybrids.
It should be mentioned that all mice falling into the category
OC, for example, are not exactly like the Japanese waltzer
in colour. For example, the fawn colour may extend over
the whole body; or, again, a new colour, lilac, may arise,
associated with pink eyes, in this generation. So long as a
mouse has pink eyes and some colour in its coat it is reckoned
as belonging to the category OC. But the number of colours
that can co-exist in a mouse with pink eyes is limited; for
example, neither a dark grey nor a black mouse ever has
pink eyes.

Now let us look at the posterity of the three kinds of mice
denoted by the formule OO, OC, and CC. O0’s, i.e. albinos,
when mated together produce only albinos; OC’s also when
paired breed true with very rare exceptions; while the off-
spring of CC x CC fall as before into the three categories
00, OC, and CC in proportions which I have not yet
determined.

The inheritance of colour in this case is shown at a glance
in the following Table:

208

Se es a

ay
An Introduction to a Biology
00. o0ty

00 cc oC

Fah 3
Y ia a

00. 00. TEC > 00 08

A

Now let us consider the generation, produced by mating
the hybrids, from the point of view of its progression. Less.
than a quarter of them waltz. But the deficiency is prob-
ably due to the fact thatjwaltzers are constitutionally weak
creatures and are more likely to die before they reach the
age at which their characters can be recorded than other
mice are. What is of interest is that the waltzing habit is
not necessarily associated with that colour character OC
with which it is associated in the pure strain, but is distri-
buted at random over the three categories OO, OC, and CC.

We have so far confined ourselves to the description of
phenomena. Now let us consider two theories which have
been put forward to account for them; first, one by Von
Guaita associated with the name of Weismann, and secondly,
one by Bateson associated with the name of Mendel.

The theory suggested by Von Guaita was intended to
account for the results of a hybridisation experiment (similar
to mine except for the fact that his waltzers had black eyes)
carried out by himself.

He suggested that there were two kinds of factors in a
germ-cell that gives rise to an albino; one, which we may

1It may be objected that I have introduced an element of confusion
by representing one homozygote by two similar letters, the other by two
different ones, and the heterozygote by two similar ones. But this objec-
tion is successfully met by saying that my formule can only lead to con-
fusion among those students who have not been taught that such formule
are nothing more than conceptual descriptions of features of the germ-
cells which we have not yet perceived. And such beginners will be confused
anyhow.

Q 209

An Introduction to a Biology

| ae e
call M, which determines that the organism which ‘develops
from the germ-cell shall be a mouse, and another A, which
makes that mouse an albino. And similarly in the case
of the waltzer, its germ-cell contains an M similar to that
of the albino, and a factor W, which makes it what it is,
a waltzer with pink eyes and fawn-and-white coat. Now
M and M are supposed to be the same ; but A and W different
and antoganistic. So that when an albino and a waltzer
are mated it is a question which of the two factors which
are antagonistic, W or A, will be manifested in the offspring.
What happens, according to Von Guaita’s theory, is that
the two factors W and A struggle, and neutralise each other
so that neither of them is manifested in the offspring, leaving
the two M’s, which are similar and compatible, in sole pos-
session of the field. This theory accounts in a very ingenious
way for the character of the hybrid; and doubtless some
elaboration of it could be suggested which would account
for the reproduction of the three categories OO, OC, and
CC in the next generation.

The theory put forward by Bateson two years ago to ac-
count for these phenomena is that there is in the germ-cell of
an albino a factor determining albinism, which he calls g, and
similarly that there is a factor g’ in the waltzer, determining
its colour characters, which we have already called OC.

The result of the union of g and g’is a hybrid g’ g, whose
character we have already denoted by CC. The result of
the union of g’ and g—the production of a form more different
from either of them than they are from each other—is said
to be a specific result in the sense that the production of
water is said to be the specific result of the union of H, and O.
But the most striking part of this theory is that which refers
to the germ-cells of the hybrid. According to it, 50% of
the germ-cells of the hybrid bear the factor g’ and 50% g.
Now the result of the union of two hybrids each containing
50% g’ + 50% g germ-cells is the production of offspring
falling into the following categories in the proportions in-

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dicated by the numbers peer to them—25 gg’ (or 9’)
25 g’g, 25 gq’, and 25 gq, or (g’g and gq’ being the same) 25 q’,
50 g’g, and 25 g—which, the reader will remember, is the
actual result.

This proportion is simply the result of the random union
of the gametes of the hybrids, and can be illustrated by
making pairs of counters by taking one of the pair at random
from a hat containing red (R) and white (W) counters in
equal numbers, and the other of them from another hat
with similar contents. The result of a large number of
trials will be in percentage 25 RR, 25 RW, 25 WR, and »
25 WW, or 25 RR, 50RW, 25 WW. -

The difference between the above-outlined Mendelian and
Weismannian theories is that while the former tries to account
for the segregation and not for the reversion, the latter tries
to account for the reversion and not for the segregation. It
is when we fix our attention on that part of the Mendelian
theory which refers to the nature of the gametes of the
hybrid that we see what the doctrine of gametic purity really
means, how profoundly new and definite a thing that theory
is, and how widely it differs from any other theory of heredity
whatsoever.

Let us imagine that we have one of our hybrids, with
its rich brown coat and black bead-like eyes, before us; a
mouse that we might easily mistake for a wild one caught
in a trap, if we did not know its parentage. According to
the particular Mendelian theory we have been discussing,
none of the gametes of this mouse contain an element representing
the character of the animal which bears itt—namely, g’g. But
half of the gametes bear the element, g’ and half g. The
fact that 50% of the children of such hybrids are like their
parents is not due to the presence in the germ-cells of their
parents of any elements representing their own characters,
but to the chance union of g’ and g, borne by different parents.
A hybrid in this generation—F’,—is, therefore, never produced
by the union of similar, but always by the union of dissimilar,

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An Introduction to a Biology

gametes; and if an F, hybrid could multiply partheno-
genetically, none of its offspring would be like itself. This
theory as to the nature of the character-representing elements
borne by the hybrids is so remarkable that one requires very
strong evidence for it to believe it. The only evidence so
far adduced is that the proportions in which the various
kinds of young occur are those demanded by the theory ;
but this does not prove the theory to be true.

The question we have to ask ourselves in considering the
value of the evidence for an hypothesis is not “How many
cases are there which are consonant with its truth?” but
‘“‘Ts there a single case which is not?” The list of cases
in which the proportion 1: 2:1 obtains in the F, generation
is lengthening every day, and it is imagined that the value
of the evidence for this particular theory becomes greater
as the list becomes longer. The simple truth that I have
stated in the form of two questions above is often forgotten.

We are too apt to think that it is sufficient to rest content
with the many that are with us; and too ready to forget
that we ought to be up and seeking out one that may be
against us.

Are there any facts which render the above-outlined
Mendelian theory untenable? I have at my disposal two,
to only one of which will I refer now. I may say, by way
of preface, that I do not wish my remarks to be construed
as antagonistic to Mendelian theory as a whole, but merely
critical of a particular hypothesis bearing that name, which
was put forward two years ago—an hypothesis in which
Mr. Bateson ceased to believe before I did.

At a time when [ still thought that it was a useful sub-
ject for investigation to try to find out which of the two
theories, Galton’s or Mendel’s, fitted the result of my experi-
ment best, I obtained a result that was apparently conclusive
in favour of the former.

The result, which I have described before, but which I
may briefly recapitulate here, was obtained by tabulating

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An Introduction to a Biology

the difference between the results of mating two kinds of
hybrids differing not in any visible character but in their
pedigree. The two kinds of hybrids that were used were
(i.) a hybrid produced by the union of two hybrids, and (11.)
a hybrid produced by crossing a hybrid with an albino; we
may Call the former HH and the latter HA. Three kinds of
matings can be made with this material—namely, HH x HH,
HH x HA, and HA x HA. In each of these types of
union a hybrid is mated with a hybrid. So that I argued
that according to the Mendelian theory a quarter of the
population produced in each of the three cases should be
albino; but that according to the commonly accepted view
of heredity, known as the law of contribution, one would
expect the proportion of albinos to be greater in proportion
as the number of albinos in the pedigree of the hybrid parents
was greater. This was found to be the case. But it was
pointed out to me that this result was not evidence against
Mendel’s theory, unless I had established the hybrid nature
of every individual used in the experiment. ‘Have you
done this?” I was asked. “ Are there any cases of families
in unions of type (i.) where no albinos have been produced ? ”
“Yes,” was my reply ‘‘ Then one or both the parents of
these families were really dominants,” was the answer to me.

I did not think that this theory was true, because it
seemed to me that to say that unless a quarter of the family
produced by an animal consisted of recessives it was not
a hybrid, was a very easy way of establishing the fact that
hybrids always produce recessives in the proportion of one
in every four. It seemed that an argument of that kind
was not likely to be based on anything having any existence
in nature, but it is a strong warning not to be led away by
appearances that when I tested this theory I found it to
be true. The animals falling into the category CC in F,
are sharply distinguished into two kinds; (i.) hybrids that
will produce albinos in the proportion of one in every four ;
and (ii.) dominants which, when mated inter se, produce no

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An Introduction to a Biology

albinos at all, and when mated with albinos are dominant
over them. I have proved these two kinds to exist. But
the existence of the second of them is fatal to the suggested
Mendelian theory outlined above. For how could individuals,
whose germ-cells appear to bear a new unit g’g, arise from a
hybrid in which the germ-cells either carried an element
representing g’ or g, and never both? The suggestion that
neighbouring ova, or spermatozoa, fuse is not likely to meet
with general approval, yet it is the only one which will
account for their appearance if our Mendelian theory is
true. We have to choose between the two improbabilities :
(i.) that neighbouring germ-cells fuse, and (i.) that none of
the germ-cells of the hybrids bear elements representing
animals like them; and two probabilities: (i.) that neigh-
bouring germ-cells do not fuse, and (ii.) that some of the
germ-cells of the hybrid contain elements representing animals
like them. I choose the probabilities. But, in claiming
to have demonstrated the falsity of the Mendelian theory
described above, I do not wish to be credited with having
‘discovered an exception to Mendel’s Law” On the con-
trary, the best measure of the progress which Mendelian
inquiry has made in these two years is the fact that while
at the beginning of them the existence of hybrids that breed
true would have been regarded as a difficulty, to-day a
reasonable explanation of their occurrence has been given.

Progress in knowledge is made by the suggestion of
hypotheses, and their rejection when found to be false ;
by this means the Mendelian has been able to account for
some very complicated cases of segregation, and for reversion
in some cases as well.

It is natural to inquire how much experiments of this
kind tell us about heredity. We are told that Mendel’s Law
only applies to a very limited class of facts, that there is
only a certain very limited and definite set of characters
to which it applies, or that it only deals with the phenomena
of hybridisation.

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An Introduction to a Biology

Let us consider these objections one by one. With re-
gard to the first I would say, what I have said before, that
the service which Mendelian theory has done to progress
in the study of heredity lies partly in the facts which it has
accounted for, and partly in the method which it has intro-
duced ; and that even if Mendel’s Law has a limited applica-
tion, his method has a great future.

The second objection is merely a detailed expression of
the first; it states in what the limitation lies. Mendel’s
Law is said to apply to a very few characters, of which colour
stands out pre-eminently among the rest. And although it |
is true that the list of characters whose inheritance can
be described in terms of Mendel’s Law comprises many other
characters than colour, e.g. the shape of the comb in fowls,
the waltzing habit in mice, and even, lately, resistance to
disease in plants, it is nevertheless true that the number of
characters to which Mendel’s Law can be said to apply is
very small indeed when compared with the number of char-
acters which go to make up an organism. And it can be
said with some truth that the characters with which the
hybridiser can deal are in a sense superficial. When we
cross an albino and a waltzing mouse the result is to our
eyes remarkably different from either parent; it is like a
wild mouse, but it is a mouse. The feature in which it
differs from its parents are its colour, its progression—it
never waltzes like one of its parents—and to a certain extent
its vigour and temperament, for it is healthier and wilder
than either parent: but it is still a mouse. The charge is
brought against the hybridiser that he can only stir up the
surface, but that he cannot disturb the depths. My answer
to this objection is that it is entirely well founded; that
there certainly are two sets of characters, one which can
be affected by hybridisation, and another, a much larger
one, which cannot, and that it is legitimate to regard the
former as upper and the latter as lower. By saying this I
do not mean to subscribe to the view that recently arisen

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An Introduction to a Biology

characters have less tendency to be transmitted than old
ones. The case of snails will illustrate my meaning. In
Helix nemoralis the unbanded condition is dominant over
the banded. Now, it is probable that some form of banding
is more ancient than colourlessness, and still more probable
that some form of colouring, at any rate, is more ancient than
colourlessness, yet absence of colour is dominant over colour.
But my point is that in crossing these snails the only thing
affected is colour; this is almost true when H. nemoralis
is crossed with another species, H. hortensis : it is not quite
true, because the cast of the spire of the shell is also altered,
but the main thing which is affected is the colour. The
animal was a snail, a Helix, before it had any definite colour ;
and, even after it had become stamped as Helix, probably
underwent many alterations in coloration. I hold that it
cannot be denied that the characters with which one deals
are in this sense superficial. But I do not think that this need
be regarded as a damaging admission by the hybridiser. On
the contrary, I hold that the recognition of a limit between the
two sets of characters—alterable and unalterable—is desirable,
and that the discovery of the difference between the kinds of
characters which it separates would be intensely interesting.
The objection that the Mendelian only deals with hybridi-
sation phenomena—doubtless very interesting and important
phenomena, it is often perhaps semi-ironically granted—
must be met. Those who urge it complain: “ It is all very
well to tell us about hybridisation—about the result of the
union of unlike; we want to know about the union of like.
Hybridisation seldom occurs in nature, and when it does the
results are more perplexing than in the case of crossing
domesticated breeds. What we want to know is, ‘ What
is the mechanism by which the similarity between parent and
son is brought about?’ The existence of a form Triton
Blasi, which is a cross between 7. marmoratus and T. cris-
tatus, is undoubtedly interesting, but it is an anomaly. I
want to know how it is that the offspring of the crested newt
216

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\ An Introduction to a Biology

is like its parent. And this youcan’t tell me. I want to know
about normal heredity ; you give me nothing but information
about abnormal. I ask for bread, and you give me what is
to me a stone; interesting and curious, but still a stone.”

I should answer objections of this kind by asking, “ But
why abnormal?” Why should we regard the disintegration
of biological units as more “‘ abnormal ” than that of chemical
ones? It is only by experiment with “abnormal” pheno-
mena that the chemist has progressed. If he had stuck as
rigidly to the observation of ‘‘ normal” water as those who
bring this objection against the hybridiser would have him
do, he would know as little about the chemistry of water
as the biologist did about heredity before he began to
experiment with it.

But this answer, though it sounds plausible enough at
first hearing, can only be thoroughly satisfactory to those
who urge this objection if we can show them that the appear-
ance of abnormality is merely due to the fact that we are
dealing with normal units in an “abnormal” condition (the
result of disturbance by cross-breeding), and if we can show
them that we really are not dealing with an abnormal
hereditary phenomenon.

Now what are we to understand by abnormal? The
most definite formulation of what is meant by abnormality
in heredity is that of Dr. Archdall Reid. According to him,
alternative inheritance has been evolved as a means of
keeping the sexes separate, or, to put it in a teleological
way, of ensuring that an individual shall be either a male
or a female. When the alternative mode of inheritance
first became differentiated it was only sex which was in-
herited in this way. But just as sex, so to speak, sometimes
makes a mistake, and trespasses on forms of heredity which
do not belong to it, and blends in inheritance, with the result
that a hermaphrodite is produced, so sometimes not-sexual
characters, albinism for example, trespass on the mode of
inheritance reserved for sex and are inherited alternatively.

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An Introduction to a Biology

Mendelians, says Dr. Reid, have lately suggested that the
inheritance of sexual characters may be Mendelian. We
shall be much nearer the truth, he thinks, if we say that
the inheritance of Mendelian characters is sexual.

There is undoubtedly a parallel between the manner in
which Mendelian and that in which sexual characters are
inherited. The Mendelian view is that Mendel’s work has
provided us with conceptions which will enable us to account
for the mass of hereditary phenomena; the latest extension
of the method being an attempt to account for the pheno-
mena of the inheritance even of sex by it. Dr. Reid’s view
is that Mendelian phenomena are merely anomalies which
are the result of the accidental association of certain varietal
characters with a mode of inheritance primarily evolved to
ensure bisexuality. This view may or may not be right;
but it deserves careful consideration because one of the
most deep-rooted weaknesses of the mind is the tendency
to regard that with which we have been acquainted for
the longest time as the starting-point from which we must
proceed to other things. For example, the most hopeless
confusion characterised the attempts that were made to
homologise the body cavities in leeches so long as zoologists
persisted in regarding the coelom of that member of the
Hirudinea with which they had been longest acquainted—
the medicinal leech—as their starting-point, and in inter-
preting the state of affairs in other leeches in terms of this
one. And the question remained in darkness until a few
years ago, when Asajiro Oka showed that the ccelom of the
medicinal leech, far from being the starting-point, formed
the very last term of a series of gradual modifications of the
body cavity; and, in fact, that the anatomy of this leech
could not be understood without a knowledge of the series
of which it was the culmination.

References to recent literature on this subject will be found
in a paper by me entitled, “‘On the Difference between Physio-
logical and Statistical Laws of Heredity ” (vide supra, p. 167).

218

Vil

Some Tables for Illustrating Statistical
Correlation

(Manchester Memoirs, Vol. 51, 1907, No. 16)

It was not my original intention to preface the description
of my new Tables with an account of Weldon’s experiment.!
But I was persuaded that without such an account the
meaning of my Tables would not be evident to many. It
must be understood, therefore, that except in the matter
of presentment the first part of this paper makes no claim
to originality.

The second part contains an account of an interesting
extension of the experiment described in the first.

+

I

Let us begin at the beginning, so far as we can. In the
case of a very great number of vital phenomena we are
unable to predict exactly what the result of certain events
will be. We know that they will fall within certain limits,
but where within those limits we cannot tell. We believe
that a duck will not produce a duckling with a beak as
narrow as a snipe’s, but the exact breadth of the beak—
measured, let us say, in terms of its length—in a given
instance, we cannot foretell.

If these words ever happen to lie before the eyes of a

1:06. Weldon, W. F. R., “ Inheritance in Animals and Plants,” pp.
81-109, in “‘ Lectures on the Method of Science.” Edited by T. B. Strong.
Clarendon Press, Oxford, 1906.

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An Introduction to a Biology

biologist, the chances are that he will be inclined to ask me,
‘“ What does it matter what the length-by-breadth index of
a duck’s bill is?’ My answer to this interruption is that
so long as we are as much in the dark as we are at present
about the circumstances which may affect an animal’s or
plant’s chances of attaining maturity, any statement that
such and such a feature matters or does not matter is un-
warrantable. .

But let us return to our argument. Some living things
are variable. We may adopt two attitudes towards this
variability. We may either say that it does not matter
and ignore it, or we may suspect that it may matter and
measure it. In my opinion, evidence does not justify us
in adopting the former attitude. Statisticians have pro-
vided us with a method for measuring this variability. But
we usually want to know more than this; we want, if pos-
sible, to measure the closeness of the relation between two
such variable things. Statisticians have again provided us
with a method which enables us to measure the closeness of
that relation in which biologists are most interested, namely,
that between parents and children.

The first step in this method is to construct a Correla-
tion Table. How this is done is best explained by giving an
account of Weldon’s beautiful experiment. The variable
phenomenon he dealt with was the number of dice, in a
throw of 12, which fell so that faces with 4-or-more pips
on them were uppermost. When we throw a single die it is
an even chance whether it falls so that a face with 3-or-
fewer pips on it lies uppermost, or whether a 4-or-more-
bearing face lies uppermost. Therefore the most probable
number of dice with faces bearing 4-or-more uppermost in
a throw of 12 is 6, but the number may be anything between
0 and 12 inclusive, though these extreme results occur very
seldom. Here is a list showing the frequency with which
the 13 possibilities occurred in a thousand throws which
I have made:

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An Introduction to a Biology

Result of

Throw. Frequency,
0 Duy et ae
1 3
2 15 f
a 55 f
4 110 food COAL
5 208 (= \
6 223 Ween
7 179 fe
8 129 miceatbbe
9 64
10 1]
11 2
12 1

Imagine that I am before you and that I have 12 dice in
a dice-box. J shake it and throw them. The result happens
to be 7 dice with 4-or-more-bearing faces uppermost. I
pick up all the dice, put them back into the dice-box, shake
it and throw them again; the result happens to be 5 such
dice. What I want you to observe is that in this pair of
throws the two throws which compose it are absolutely inde-
pendent of one another; the result of the second is not
affected by the result of the first ; a knowledge of the result
of the first does not help us to predict the result of the
second.

Let us think of some way of making the two throws in
such a pair dependent, of making the result of the second
affected by the result of the first, and of bringing it about
that a knowledge of the result of the first shall help us to
predict the result of the second.

I suggest to you that a good way of doing this is to
leave half the dice, which formed the first throw, lying on
the table, and allow them to form half of the second throw.
If I do this, the second throw will consist of six dice lying
exactly as they did in the first throw and of six dice thrown
afresh. Six of the twelve results which determine the total

221

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An Introduction to a Biology

result of each throw will be common to the two throws of a
pair.

But you will say, “How will you know which six dice
to leave on the table? You will not be able to help leaving
the ones showing 4-or-more down and picking up the others,
except by making it a rule not to do so. And that would
introduce too much complication. It seems to me that it
will be very difficult to make the decision as to which dice
shall be picked up and which not a matter of chance and
not of choice.” This objection is quite reasonable, but the
difficulty is not insurmountable. All that is necessary is to
make six of the dice different from the other six. This is
easily effected by leaving them for a few hours in red ink.
It does not matter whether we make it our rule to leave
the red or the white dice down on the table when we gather
up the six dice to make the second throw. Let us decide on
the red.

We can now start to make a pair of connected throws, in
which the decision as to which dice pass over undisturbed
from the first to the second throw is a matter of chance and
not of choice. I put all the dice—the 6 red and the 6 white
—into the dice box, shake it about, and throw the dice on
to the table. The result happens to be 6.1 Now I gather
up the white dice, put them into the dice box, and throw
them. In describing the results of the second throw I count
the red as well as the white, although only the latter have
been thrown a second time. So that half of the results which
determine the total result of the first throw are exactly the
same as half of those which determine the total result of
the second. The two throws are connected together. For
instance, let us consider the maximum possible difference
between the two connected throws and compare it with the
maximum possible difference between two independent

1The number describing the result of a throw means the number of
dice exhibiting faces with four-or-more pips on them uppermost in that
throw.

222

An Introduction to a Biology

throws such as we started by making. The maximum possible
difference between two independent throws is twelve. A
12 may follow a 0. Or a0 may follow a 12.

But in the case of two connected throws the maximum
possible difference is 6. It may happen by all the red dice
showing 4-or-more and all the white ones 3-or-less in the
first throw, and by all the white ones showing 4-or-more
when thrown again (that is, by a 12 following a 6); or by all
the dice showing 3-or-less in the first throw and the white
ones all showing 4-or-more when thrown again (that is, by a
6 following a 0). The number of ways in which the maximum
difference between the two throws may be attained is given
by the number of pairs of figures that follow. The first figure
in each pair indicates the result of the first throw in that
pair; the second that of the second: 0-6, 1-7, 2-8, 3-9,
4-10, 5-11, 6-12, 7-1, 8-2, 9-3, 10-4, 11-5, and 12-6. The
essential point is that 6 is the maximum possible difference.

But you see how seldom it is likely to occur. It depends
on all the white showing the opposite kind of face upper-
most in the second throw to those which they exhibited in
the first. The fact that it does not occur often, however,
does not concern us now. What concerns us at present is that
the maximum possible difference between the result of a
pair of throws connected in the way we described above is
6, whilst that between two unconnected throws is 12. The
two results in the “ connected” pairs are, as it were, chained
together. We may compare the two results in unconnected
pairs to a couple of dogs, not chained together, in a show
stall at a dog show. Let us imagine the stall to be 12 feet
long and each foot to be marked on the base of its frontage
so that, as you stand looking at it, the left boundary of the
stall is over the 0 and the right over the 12. The two dogs
could, if they wanted, lie as far away from each other as
the size of the stall permitted, namely one over the 0 and the
other over the 12. We may compare the two results in
“connected” pairs to two dogs in such a stall leashed

99
“—_

‘ Pe

An Introduction to a Biology

224

ELE.

4.5
4.5
9.8
7.6
5.8
4.8
7.5
8.7
5.5
5.8
8.7
7.6
5.6
5.8
8.7
7.8
5.7
5.4
8.5
8.8
“il
2.6
5.7
6.6
6.5
6.6
5.7
3.5
7.8
6.5
5.5
8.7
9.6

“

tae |

a

7.6 7.7
4.2 7.8
5.7 6.8
8.8 5.7
Ts 5.5
8.7 5.4
9.9 4.6
8.7 6.3
9.8 4.7
6.4 1.9
3.3 4.4.
4.5 4.6
G10) OS
5.5 8.6
3.7 6.8
6.6 5.4
9.6 7.8
6.8 6.9
8.7 5.8
4.3 4.7
6.6 8.10
2.01) JO8
5.4 6.10
5.7 6.4
6.6 7.6
8.5 ci
4.4 9.9
5.3 4.4
8.7 7.8
8.5 3.6
8.6 4.4
6.6 3.7
6.7 4.3

An Introduction to a Biology

aie
8.7
10.7
4.6
aie
6.7

An Introduction to a Biology

together by a 6-foot chain. If one of them wishes to sleep
over the 0 the other has to lie in the middle of the stall
over 6. If after a time the latter insists on moving to 12
the former must put up with 6. And similarly with inter-
mediate positions. This parallel illustrates only the maxi-
mum possible difference between first and second throws
in “connected” and “unconnected” pairs. To find a
parallel for the most usual difference between first and
second throws in connected pairs we should have to imagine |
the leash connecting the dogs to be made of a piece of elastic
with a maximum stretch of 6 feet.

We must return to the dice. Let us make a number of
pairs of such connected throws, and see what the result is.
On pages 224-225 are given the results of 500 such pairs.
The Roman numerals at the top of each column mean that
the left-hand figures give the results of the first throws; the
right-hand ones those of second throws.

The list does not show very much in this form. If you
look through it you will find that a high number is as a
tule followed by a fairly high one, and that a low one is
usually followed by a fairly low one. But this is not pre-
sented at all vividly to the eye. What we want is some
means of finding out, without the labour of counting through
the whole series, the number of times a given result in a
first throw is followed by a given result in a second. This
want is supplied by the so-called Correlation Table. Here
is one (see next page) on which are exhibited the results of
the 500 pairs of throws detailed on pages 224-225:

The Table proper is bounded at the left and top by
single lines, and at the right and bottom by double ones.

It is made up of 169 squares. A horizontal series of
these squares is spoken of as a row; a vertical series of them
as a column. So that we may say that the table consists at
once of 13 horizontal rows, each of which is made up of 13
squares; and of 13 vertical columns, each of which is lke-
wise made up of 13 squares.

226

we |
An Introduction to a Biology,

The numbers at the top of (but outside) the columns
stand for the various possible results of second throws, which;
as we know, may be anything from 0 to 12. The numbers
at the left-hand end of (but beyond) the rows have the same
signification, except that they refer to first throws.

At the base of (but below) most of the columns are num-
bers which signify the number of times the event, indicated

Second Throws.

First Throws
N

| Eaah
OETA
Bebo tbh. bid ts Bee

EL fia fas [5 foe [ar Jug [i [23 Jo] | oo

by the figure at the top of the column, happened in the
500 second throws. For example, a 2 occurred 12 times;
a 3, 25 times; a 4, 51 times; and soon. At the right-hand
end of (but beyond) most of the rows are numbers which
signify the number of times the event indicated by the
figure at the left of the row happened in the 500 first throws.
For example, a 1 occurred 3 times; a 2, 8 times; a 3, 24
times; and so on.

ad
19
bel
pat. {13
es
ae

227

*

An Introduction to a Biology

So far, we have only referred to the figures outside the
Table, and I hope I have made clear to you what they mean.
Now, we must turn our attention tothe table itself. It will
be found that the numbers at the bases of the columns are
the sums of the numbers in the columns above them; and
that the numbers at the right-hand ends of the rows are
the sums of the numbers in the rows to the left of them.
Each column intersects all the rows, and each row intersects
all the columns of the Table. Every square is part both of
a column and of a row.

What is the meaning of the numbers in the squares ?
The figure in any square gives the number of times the
result indicated by the number at the left-hand end of the
row of which it is a part happened in a first throw, and was
followed by the result indicated by the number at the top
of the column of which it is a part, in the second throw.
For example, starting with the top row, we see that there
was not a single case of a 0 thrown at all in these 500 pairs
of throws. Coming to the second row, we see that there was
one case of a 1 in a first throw followed by a 2 in the
second ; one of a 1 in a first followed by a 3 in the second;
and one of a 1 followed by a 4. Examination of the
third row tells us that there was one case of a 2 followed
by a 2, two of a 2 followed by a 4, three of a 2 followed
by a 5, and two of a 2 followed by a 6. And so on
throughout the table.

The best way to familiarise yourself with the construc-
tion of such a table is to make one for yourself from the figures
on pages 224-225. You draw a correlation table like the one
we have been examining, but quite blank; and write the
numbers 0 to 12 along the tops of the columns, and at the
left-hand ends of the rows just as in that Table. The plan
is to'indicate the result of a pair of throws by putting a dot
in one of the squares of the table. But which square? We
shall see in a moment. The first pair of throws on the list
is a 5 followed by a 3. The figure 5, denoting the result

228

An Introduction to a Biology

of the first throw, tells us in what row the dot must be.
The figure 3, denoting the result of the second throw, tells
us in what column the dot must be. The square, therefore,
formed by the intersection of this row by this column is
that in which the dot must be placed. The next pair of throws
is a 6 followed by a 7. We find the position of the square
in which the dot representing this result is to be placed in
the same way. We continue this process until all the pairs
on the list are entered; then we add up the dots, and write
the totals thus obtained, in each square; add up the figures.
in each square composing a column, and write the total at
its base; and add up the figures in each square composing
a row, and write the total at its end. The result is the
Correlation Table on p. 227.

There is one feature of it which cannot fail to attract your
attention immediately. It is that the figure-containing
squares lie diagonally across the Table. It is not very dif-
ficult to see what this means. It is the expression of a fact
we already know, namely, that low numbers are associated
in a pair with low numbers, high ones with high ones, and
intermediate ones with intermediate ones.

We are now approaching the outskirts of a vast sub-
ject. The task I set myself was to show you the way to it;
but not the way into it. Having given you an account of
Weldon’s device for illustrating correlation, I will go no
further, but will leave you in the hands of the statistician,
who, I may perhaps tell you, will provide you with a means
of working out from such a Table a number called the cor-
relation coefficient, which is a measure of the degree of con-
nection between the two things you are dealing with. In
the case of the dice throws connected in the way we have
just been considering, this number will be approximately
-5. In the case of Table 0 (p. 282) it will be approximately
0; in the case of Table XII. (p. 288), approximately 1.
In fact, quite generally, if m dice are left down in the 12 the
coefficient is m/12ths.

229

TABLE 0.

TaB.Le I.

9

Phils ee
Ha
4|2) 1 | ie
ae:

bt
419 | 3 32 |
ae 12 ame)
Spl be
CAN i
EEC HE
RN
39 [8 [2 | [poo

4 b
iE ee:
Ee aoe
a 3

5
Bae
Hie 15 |2
8 40/05
8 413 [14
12 | 10
cs
}
Se, ae
47 (02. | 44 [109] 67

PCE Begee =
Oo sash Re SeR Sete

©

242

TABLE II.

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aatisiehietl Te
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So A Oo SO

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Taste IV,

en oes: te jaisielejs| 93!

Cth ii Peer
a

CCS sles

el

25m aR
fe isis iy tie
sisieiefete tet Tle

TABLE VII.

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Bua ae 4 ee

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. SS EO ee eee

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TOD PETES Es a, I ee ae Sa

TABLE IX.

Facing p. 288

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VIll

Some Conditions of Progress in Biological
Inquiry

(Manchester University Biological Society. Opening Address
for the Session 1906-7)

“* You who speculate on the nature of things, I praise you not for
knowing the processes which Nature ordinarily effects of herself, but
rejoice if so be that you know the issue of such things as your mind
conceives.’ —LEONARDO DA VINCI.

Mr. PRESIDENT, LADIES AND GENTLEMEN,

Your invitation to me to read a paper to you at the
opening meeting of this session of your society gave me
great pleasure. If you had thought me an efficient demon-
strator, you would have made me a present of a silver clock ;
but it appears that you were clever enough to estimate at
its real value my ability in that capacity. If you thought
that I had on occasion something interesting to say to you,
you would invite me to give the opening paper of the session
to this society. And let me tell you that the verdict you
pronounce on me by having done so is far more gratifying
to me than that expressible by the presentation of a silver
clock. ‘‘ He who can, does; he who cannot, teaches.”

In the course of settling on a subject for my remarks I
have been struck with the fact that, notwithstanding the
great diversity of topics of addresses of this kind, and not-
withstanding the variety of the reasons alleged for choosing
them, they have one feature in common—namely, that they
are interesting to the lecturer. This common feature deter-
mining the choice of a topic is obviously in many ways a
desirable one. But a human mind is such that it often fails

239

An Introduction to a Biology

to perceive that what is interesting to itself is not neces-
sarily interesting to other minds. And when you come to
consider the kind of things in which a man becomes deeply
interested, you will realise that the very fact of their being
interesting to him is the reason of their being uninteresting
to others. For the only things which can beget a real interest
in a man are new things, especially things for whose bringing
to light he is responsible.

The fact that we are responsible for the bringing to light
of these new things—our discoveries, our intellectual offspring
—accounts for our own absorbing interest in them and for
the belief that others take a similar interest ; and makes us
try to go further into them and find out everything about
them in the most detailed manner possible. The more we
do this the more does each new little thing we find out swell
in importance in our eyes, until at last we enter a state in
which we can see nothing but this new thing; and even if
we do not get so far as to believe that nothing else exists, we
at any rate very soon come to think that it is more important
than anything else. The modern scientific belief that the
world is much as we see it, and is not peopled by hosts of
spirits, is not without its disadvantages. For if we begin
by saying that the world is what we see, we may end by
coming to believe that what we see is the world. And if we
are not careful we may ultimately lose the power of detach-
ing ourselves from the little world we have created around
the thing which we have discovered, and of viewing it with
the same degree of magnification as that with which others
look at it. So it often comes about that a man chooses as
a topic some minute point with which he has himself been
engaged, and that he is apt to conclude from the fact that
he is absorbed in it that it will be interesting to his hearers.
' I shall therefore try to escape from the possibility of tiring
you in this way, by not talking about any experiments which
I have been making. And I propose to invite your attention
to a topic which deeply concerns every student of nature.

240

An Introduction to a Biology

The aim of the biologist is to discover all about life; and
a biologist is successful in proportion as he contributes to
our understanding of vital phenomena. For example, we
know something, though very little, about the nature of
fertilisation ; but we know next to nothing about the nature
of heredity, and absolutely nothing about the causes which
determine the sex of animals. We feel fairly sure, now, that
animals and plants have descended from pre-existing ones,
and that the diversity of forms which exists at the present
day is the result of this descent going on hand in hand with
a gradual modification. But we do not know how this |
modification has taken place. We are accustomed to express
our belief in the fact of evolution; but no one pretends to
know in detail how it has been brought about.

These, then, are some of the unsolved problems in biology.
And a biologist is successful if he proves one of these mys-
teries less of a mystery. Now inasmuch as none of you here
will, I suppose, question the desirableness of improving natural
knowledge, you will, I conclude, allow that it is profitable to
discuss the question, What is it that.makes a successful
biologist ? in order that we may quicken our progress in
biological discovery. Some of you here will form part (as
indeed some of you already do) of the body of investigators
whose business is the study of life; and it is meet that we
should consider what are the things which retard progress
in this branch of knowledge, and what are the things which
help it. It is my object this evening to suggest lines of
thought which may help you to form a definite opinion on
this matter.

The process by which the biologist performs his task con-
sists of two stages. The first is the description of phenomena,
the second is the formulation of theories to account for them
Description is a record of what we perceive ; interpretation
what we achieve by reasoning. And, broadly speaking, I
think it is reasonable to hold that the difference between man
and the other animals is that whilst the other animals do

Q 241

An Introduction to a Biology

not get much further than perception, man goes on to reason
about the things he perceives. But you see, of course, that
he must perceive the things first, before he can go on to
reason about them.

Now you know that man in his attempts to account for
things has repeatedly gone astray. Even those people who
are stupid enough to think that the ways in which we account
for things to-day are right and true and everlasting are not
blind to the fact that the theories by which their predecessors
tried to account for things were wrong, false and transient.
But we are not concerned with that point now. The point
is, we may take it as established that in the second part
of the process, in trying to account for things, man has gone
hopelessly astray. Are we sure that in the sphere of descrip-
tion there is no chink into which error may creep? Let us
make quite sure of this before we see to keeping our machinery
of reasoning in order. For unless we are perfectly sure that
we see things aright, it is manifestly absurd to try to account
for them. We cannot interpret nature until we know what
nature is. Our first business is to describe ; when we have
done that properly we can go on to explain. We ask our-
selves: Has error characterised our description of things
to the same extent as it has our attempts to account for
them? And the answer I suggest is: Yes, but in a less
degree.

The question naturally suggests itself: How can we go
astray if we merely describe things? Surely the same thing
cannot be two different things at the same time. And the
answer I should make to this is that, if one can be sure about
anything, one can be sure that a thing cannot be two different
things at the same time. But we hardly ever do merely
describe things. Practically all description of natural pheno-
mena is made with a view to its bearing on some general
problem, and the describer is expected to give some pro-
nouncement as to the direction in which his work points,
whether it be for or against one or other of current rival

242

An Introduction to a Biology

theories, or for a theory he himself has put forward. Now,
although I have just described the method of investigation
of nature as consisting first of description and then of inter-
pretation, it is only in quite recent years that the necessity
for this chronological sequence has been recognised. The
merest glance at the history of human thought suffices to
show that the farther we go back in time the more does the
proper order of description and interpretation tend to be
reversed. We need go no farther back than the Middle
Ages for an example of a time when a complete interpretation
of the universe was not only attempted but believed in so
firmly by men that they killed those who denied it. Yet
not the smallest fraction of that universe had been trust-
worthily described.

To-day we profess greater modesty as to the complete-
ness of our interpretation. Yet those of us whose knowledge
of nature is culled from textbooks written by people who
talk about natural processes being governed by immutable
laws, have got.no further than handing over the government
of the universe from a hierarchy of spirits and demons to
one of principles and laws. Kven those men of science who
see that this notion is nonsense make the most unwarrantable
assumptions. We are told that living nature is orderly and
not chaotic; that the more we find out about it the more
simple will it become and the less complicated; that if a
fundamental principle is discovered in the case of animals,
it will be true also of plants; and so forth. These things
may be so. But it is our business not to assume that they
are, but to find out if they are. And we are far from knowing
that yet.

As it with our general view of nature, so it is with our
investigation of particular problems. At the threshold of
a piece of research, Interpretation does not politely wait at
the door and say, “* Allow me; Description first,” but both
rush in together without ceremony, hand in hand; with the
result that the work of Description is always influenced by

243

An Introduction to a Biology

the suggestions of Interpretation, and always will be; for
they are inseparable companions. The former is tedious
without the latter; the latter is not countenanced without
the former.

We have seen that description is influenced by interpre-
tation. We have seen that interpretation is not always
right. We therefore cannot escape the conclusion that
description is sometimes wrong. And even if this argument
did not prevent our escape from this conclusion, we could
not escape from it unless we shut our eyes to the hosts of
instances of it that are afforded by a study of the history
of the interpretation of nature. The pages of that history
are strewn with the carcasses of descriptions of things that
are not. Instances of such will crowd up into the mind of
the reader. For who is not familiar with numbers of cases
in which a man with a definite interpretation of a pheno-
menon in his mind has expected to find such and such a
thing, and has found it, in spite of the fact, incontrovertibly
established by general and impartial testimony afterwards,
that nothing of the kind existed all the time ?

The upholders of the doctrine of evolution, as opposed to
that of epigenesis, asserted that a miniature edition of the
adult bird could be seen in the hen’s egg. Hartsoeker
actually made a drawing of a spermatozoon in which a little
man is seen crouching with his knees tucked up to his body
and with his hands holding his knees in place.}

No sooner had the wonderful cytological phenomenon
which bears the name of the quadrille of centres been de-
scribed in the animal kingdom than it was promptly dis-
covered in the vegetable one. We know now that it exists
in neither.

The leech Pontobdella is said to have a lateral blood-vessel
lying inside a lateral sinus, a part of the celom. There is,
as a matter of fact, only one vessel, and this is homologous

1 See Delage. “ L’Hérédité et les grandes problémes de la Biologie
générale,” p. 380.

244

An Introduction to a Biology

with the lateral sinus of Clepsine and the so-called latera]
blood-vessel of Hirudo : in fact, all three of them are lateral
sinuses (i.e. parts of the coelom) in gradually advancing
stages of taking over the duty of the vascular system, a
process which reaches its completion in Hirudo, in which
the vascular system proper has absolutely disappeared.
But if you start from two fixed points: first the point (fixed
by observation) that the lateral sinus in Clepsine is a part
of the ceelom; and secondly, the point (fixed by tradition)
that the lateral blood-vessel in Hirudo is morphologically a
blood-vessel ; and if you try to interpret the state of affairs ~
in an animal, Pontobdella, which is intermediate between the
two animals bearing these two fixed points, and if you strive
to show how the transition from the one to the other may
have been effected, the most natural thing that suggests
itself is that they both exist in Pontobdella, one inside the
other. They do not. But that did not prevent their being
described so. The reader can see an actual drawing of the
one tube inside the other by turning to page 518 of Sedgwick’s
“ Student’s Text-book of Zoology.”

Further instances of this type of visual disease will prob-
ably recur to the reader’s mind if he has devoted himself
to the investigation of nature.

Before we turn to the consideration of the question of
the most desirable relation between description and inter-
pretation, let us pay some attention to interpretation itself.

When we say that we have interpreted a phenomenon,
we think we have succeeded in seeing deeper into it; that
we have succeeded in penetrating below the face of the clock
and have made out the works. Now it 1s, in my opinion, very
important to consider what right we have to say that we see
deeper into a phenomenon when we interpret it. I hold
that we do not.

I can see the face and hands of a large clock—such as
the one outside in the Quadrangle—from a very considerable
distance. But in order to be able to understand the works,

245

An Introduction to a Biology

IT have to go upstairs behind the clock and examine and touch
the various wheels, and minutely trace out how they work
together. That is to say, I could describe the face of the
clock and the changes in position of the hands, the difference
between the speed of the two, and so forth, from a dis-
tance of 50 yards. But in order to be able to account for
these phenomena, I must come as close as possible. So that
we may say that, in this case, all that we need, to be able
to interpret the phenomenon, is opportunity of coming closer
to it (provided we are not in so low a state of intellectual
development that we interpret it as the result of the agency
of spirits). We may put it another way: we may say that
interpretation involves the coming to closer quarters with
a phenomenon ; it means a decrease in the distance between
the eye of the observer and the thing observed. And all
this is perfectly true so long as the constituent parts of the
mechanism under investigation are of such bulk that they
can be perceived and handled individually by man. Now
the constituent parts of a clock are, for the simple reason
that the mechanism is the work of man. But the constituent
parts of vital mechanism are not; yet we continually act and
speak as if they were.

We are nowadays always sighing with relief at our happy
deliverance from the old anthropomorphic interpretation of
the universe. But are we emancipated? Not a bit. We
are still slaves. What right have we to imagine that the
mechanism of the things around us should be of such a size
that it bears that relation to us which will enable us to under-
stand it if we only look close enough? Why should it not
bear that relation to bacteria, or to some other beings as
much smaller than bacteria as bacteria are smaller than
ourselves? What are we that we should expect this ?
Nothing but the last term of a series of changes in one direc-
tion of mammalian development. We are so incapable of
estimating our own place in the universe that we have not
yet got out of the habit of referring to all the other animals

246

An Introduction to a Biology

as the lower animals; nor of marvelling at nature for having
evolved such wonderful creatures as ourselves. ‘“‘ What a
piece of work is man!” wecry. Yes. What indeed! What
sort of a piece of work should we think a clock that stopped
eight hours out of the twenty-four? We get some idea of
how far we fall short of any satisfactory standard of activity
and endurance from the fact that when a mutation that
can dispense with sleep (Napoleon) does arise, he nearly
conquers the world single-handed.

It is certain that we think we have a right to understand
things in nature. How many naturalists, when they have .
arranged their oil immersion, peer down the microscope
and think that they alone are privileged to view the ultimate
structure of protoplasm ?

The question whether life on this planet was created or
not does not matter. The point to insist on is that it was
not created by us. Yet we are continually acting as if it had
been. We believe that when we interpret a thing we are
seeing closer into it; on the analogy of the clock. We forget
that we have not created the thing in nature. We look closer
into it and at first can see no works; gradually we think
out what the works must be like; we retain the image that
we invent of them in our minds, and then come away and
tell everyone we have discovered the works. Nageli and
Mendel both looked at the phenomenon of hybridisation.
Nigeli saw only the face of the clock, and it meant nothing
to him. Mendel thought he could discover what the works
were like by the various things that happened on the face
of the clock, and it is true that his theory of the works corre-
sponds with what happens on the face. Yet he never saw
any part of the works. Have they any objective existence,
then, outside Mendel’s brain? Probably something faintly
like them has. The point I want to bring out is this. The
interpretation by man of a work of man (e.g. a clock) may
be said to consist in the shortening of the distance between
the eye of the observer and the thing observed. Is it so in

247

An Introduction to a Biology

the interpretation of a thing which is not the work of man
—a thing in nature? No; emphatically no.

Let us regard the distance EP between the eye and the
phenomenon, when the latter is just so far away that it
can merely be perceived and nothing more, as 10 units of
linear measurement, and the distance EJ between the eye
and that part of the brain which imagines (wherever it may
be) 2 units. The interpretation of the clock consists in de-
creasing the length of the line HP by dividing it by 1,000,
say. But what about the interpretation of natural pheno-
menon ? Does it consist in the decrease of the length of
the line HP? No. It consists in increasing it by the length
of the line HJ. So that whilst we think that the more we
interpret a phenomenon the more we are getting at close
quarters with it, as a matter of fact the inverse relation is
what really obtains. If we admit that interpretation con-
sists in going beyond the limits of our vision, we have to ©
admit that what we do on the other side of that hmit is
not seeing, but imagining. And really it is tacitly conceded
that this is so. For when a particularly ingenious theory
which, we think, enables us to come to close quarters with
the inner mechanism of a phenomenon is put forward, our
praise is not for the marvellousness of the mechanism dis-
covered, but for the ingenuity of the brain that conceived
it. We praise Mendel, not the mechanism of segregation ;
how could we? We have never seen it. We say, “ What
intellect!” and not “ What works!” Moreover, it is easily
proved that this is so, for if interpretation really meant a
making out of the works, there should be greater unanimity
in the sphere of interpretation than in that of description ;
because the closer we can look, the more accurately can we see.

I hold, therefore, that the view that interpretation signifies
a coming to closer quarters with a thing is baseless.

Another very fertile source of error in interpretation is
one which probably results from the nature of the mechanism
of thought. For whether we consider it to be a liquid run-

248

An Introduction to a Biology

ning in tubes, or the result of the vibration of molecules,
it is certainly true that the more often a certain thought has
been formulated the less difficult is it to forget it. The
oftener we read a book the better do we know it. Yet this
property of the brain has dire consequences. A thought
merely by being formulated a great number of times becomes
fixed. I am thinking not so much of thoughts that occupy
a prominent place in our mind, or thoughts in which we are
particularly interested, but of thoughts which occupy a back
seat, which are used as a starting-point for trains of thought.

Sir Harry Johnston had heard about the animal which.
we know now as the okapi from the natives, who called it a
donkey (doubtless because of its large ears), and this, coupled
with the fact that a strip of skin from its rump, which the
native soldiers used as bandoliers, was beautifully striped,
led him to conclude that the animal was a new species of
zebra. How long Sir Harry Johnston went on thinking it
must be a zebra I do not know. But when he came to explore
the forest for this animal, he so little questioned the idea
that it could be anything but a zebra, that he abstained
from following any artiodactyle spoor he came across be-
cause, he thought, it belonged not to the beast he was after,
but to some great forest eland. In the light of what we
now know of the okapi it is probable that, if the idea that
the animal was a zebra had been only just so little less firmly
implanted in his mind as to allow him to try one of the
spoors of the cloven hoof, he would have been rewarded by
a sight of this wonderful animal.

It is probably this feature of the mind which makes us
so incapable of recognising that a thing which we have come
to regard as a starting-point from which we may proceed
to the discovery of new things may not really be the starting-
point, after all.

In heredity the theory of unit-characters owes its wide
acceptance to-day to the glare of light which has been directed
on to Mendelian hereditary phenomena. Some of those who

249

An Introduction to a Biology

have been engaged in investigating this phenomenon have
suggested that the difficult problem of the nature and deter-
mination of sex may be elucidated by applying Mendelian
conceptions to it. But Dr. Reid says: “‘ You have got hold
of the wrong end of the stick. The Mendelian phenomenon
is not fundamental at all. It is merely an anomalous here-
ditary process. The inheritance of sex is the real starting-
point. Mendelian phenomena are merely due to the acquisi-
tion by non-sexual characters of the mode of inheritance—
the alternative—which was primarily evolved to keep the
sexes separate. Mendelian phenomena do not form a starting-
point, but are the last terms of a series.” 1 I do not express
an opinion for or against this view. I am merely concerned
now in pointing out that the Mendelian has great difficulty
in adopting it. To him it is simply unthinkable nonsense.
His feelings are like those of a man who, standing on the
top of a pyramid which he himself has constructed, is told
by a cheeky one down below that the pyramid is the wrong
_ way up, and that he must come off it and put it the other
way up. The reason that the man on the pyramid absolutely
refuses to do anything of the kind is that he has spent years
in building it. The reason that the man down below is
able to see that the pyramid is really upside down (sup-
posing that it is) is that he has played no part in its erection.
Indeed, in the instance we are discussing, he only had his
attention drawn to its existence a year before he saw that
it was upside down.

There is seldom any difficulty in convincing people of the
existence of a particular form of mental disease; but it is
never easy to convince them that they themselves are suffer-
ing from it. We are ready enough to point out the frailty
of the human intelligence, but are (perhaps unconsciously)
apt to exclude our own from the general condemnation. I
f< 1A fuller discussion of this point will be found under my name in the
proceedings of the International Conference on Plant-breeding, 1906,
Vide supra, pp. 217-218.

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An Introduction to a Biology

remember a drawing in one of the German humorous papers
of a young nincompoop lolling back in an arm-chair and re-
marking to his elderly host: “‘ Es ist merkwiirdig, Jeheim-
rath, wie viele dumme Leute es in der Welt giebt”; and
receiving the answer, “ Tja, aber es ist immer einer mehr als
man denkt.”

So, in case the reader should think that I imagine that
T am not as liable to this disease as I think others are, I well
now record in considerable detail a case which revealed to
me the appalling susceptibility of my own mind to this
fearful complaint.

In the spring of this year I had occasion to go to Ischia,
an island near Naples, for the purpose of convalescence.
While I was there I collected, in the deep mountain gullies
worn out by the hot streams in the volcanic tufa of which
the island is made, six toads of the species Bufo viridis. The
first stage of my journey back to England was to Naples,
whither I went with the toads. Whilst I was there I gave
some of them to a friend of mine who was working in the
laboratory there; but when, after I had seen the last of
him, I tried to remember how many toads I had given him,
I could not do so, though I was sure it was either one or two.

From Naples I started on a North German Lloyd ship
for England. The toads were in two tin boxes, which in their
turn were in a wicker trunk I had bought in Naples. On
the second day out I thought it was time to feed the toads,
so I provided them with pieces of ox tongue cut up small.
At Gibraltar [ was joined in my cabin by an elderly Scottish
doctor, who was travelling for rest after a nervous break-
down ; I occupied the upper berth, he the lower. The noises
heard during the night on a ship bounding in the Bay of
Biscay are many and varied. But notwithstanding the num-
ber and variety of the sounds, I was almost sure I could
detect the croak of the toads, which is rather shrill. I was
naturally a little uneasy lest my cabin companion should
hear the noise and inquire about its origin, but 1 comforted

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myself with the thought that the next night I could remove
the cause of my uneasiness by putting the trunk containing
the toads out in the passage. For I must mention that out
of a general regard for the state of my companion’s nerves,
and on account of a definite statement by him at dinner that
he could not stand toads at any price, I had not informed
him that I had any with me, and still less that there was a
party of them under his bed.

So the next evening, before dinner, I removed the trunk
to the passage. After lying awake for about an hour, I was
gradually dozing off when, to my horror, I heard the shrill
croak of the night before. What was the meaning of this ?
The sickening thought suddenly struck me that one of them
had escaped on the occasion on which I had fed them, and
was now at large in the cabin; but another possible inter-
pretation was that I had only put the trunk just outside
in the passage and that between the cabin and the passage
there was a window, so that really the toads were not so
much farther off after all, and the croak I heard was from
one of the captives out in the passage.

To find out whether this comforting theory was true, I
opened the tin boxes in which the toads were, in the hope
that I might be able to find out in that way whether one
had escaped or not. But I was disappointed. There were
four toads left; but as I could not remember whether I had
left one or two with my friend in Naples, the fact that four
remained was no help. Had there been five it would have
been all right, for I knew that I had left at least one in Naples.
Having failed to discover in this way whether one of the
toads had or had not escaped, I set myself to find out whether
there was actually a toad at large in the room. This I
did by removing the trunk containing the tin boxes from
the position it occupied just outside the cabin to the end
of the passage, which was so far away that a toad’s croak
could not reach my cabin from it. It can be imagined that
that night, directly my cabin companion had put out the

ile a
=

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An Introduction to a Biology

light, I listened as intently as I could for the sound I had
heard the night before. I had listened for more than an
hour, and had already begun to congratulate myself on the
fact that a toad could not have escaped after all, when I
distinctly heard the croaking noise. I was all attention ;
and needed to be, for the creaking of the timbers of the
ship and the rattling of the rudder gear was also in my ears,
I tried to put myself in the calm, unexcited condition of
the scientific observer in order to be quite sure whether I
really did hear the sound or whether it was only that I
thought I did. And I had not been in this condition of
attention for long when I heard the noise so clearly that
there was no possibility of doubt that it originated in the
cabin. Not only so, but I thought I could hear it under
my companion’s berth. So that I leant out of my berth to
wait for the next sound. And sure enough, when it came there
was no question that it came from the quarter of the room
where [ thought I heard it first. It can readily be imagined
that I spent the night in continual fear that the noise would
sooner or later awaken my companion; and in continual
elaboration of lies to account for it if it did. However, I
resolved to have a thorough search on the morrow, and
whether or no I went to sleep finally that night, I do not
know.

On the next day J thoroughly searched the room, turning
out all the boxes from under my companion’s berth and
from under the sort of settee which occupied the other side
of the cabin. I looked in all cupboards and possible places
of retirement in which the toad might have been hidden.
But all in vain. I could not find him. And I was just aban-
doning my search when [ noticed a place where I had not
looked. It was a step, just inside the cabin door; it was
hollow and open at both ends, about two feet in length and
about two inches in height and two in breadth. I could
not get my hand into this. Nor could I force an entry
with a stick so as to drive the fugitive out at the other end,

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An Introduction to a Biology

because I could not put the stick into the open end except
at such an angle that it would not enter more than a few
inches, and it was so strongly built that I could not wrench
one side away. I could not bring myself to ask my steward
to get the ship’s carpenter to unscrew it; partly, I suppose,
because my knowledge of German, though by this time
extensive, did not reach so far as to enable me to tell the
cabin-steward what I wanted doing, and still less to enlighten-
ing him as to the reason of it; and partly because I could not
bear the thought of the merriment that would be engendered
by the possible non-discovery of the toad. However, I
derived what little comfort I could from the fact that the
next was my last night on the ship; and resolved to leave
the said instructions for the ship’s carpenter in order to save
any elderly person who might occupy the cabin after me
the agony of terror, or even the possibility of death, that
would be quite likely to attend the discovery of a toad in
their cabin; and to impart these instructions to my steward.
at the moment of leaving the ship and of tipping him, so
as to escape by the former the bitterness of witnessing the
merriment caused by the conceivable non-discovery of the
toad, and to drown by the latter any objection he might
_ raise.

That night it was a very long time before I heard any
sound of the fugitive; in fact, so long that I was dozing off
to sleep when I heard the first one. I was soon alertly
attentive to discover whether I had only dreamt I heard
it—which would not have been unlikely—or whether it had
really begun again. I had not to wait long. The shrill cry
soon rang out in the stillness of the night; the night was
still because we had reached Southampton Water and were
anchored there. I listened to discover if I could trace the
croak to the hollow step just inside the door; but the next
time I heard it, I was almost sure it was in its old position
under my companion’s berth. The next time it was so
plain that I thought I could be certain that it was in his

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‘ An Introduction to a Biology

berth. This was a terrifying thought. I shuddered to
imagine what might happen if the old man woke up and
put his hand on the clammy thing. To make quite sure, I
argued to myself in this way. If the toad really is in his
bed it is reasonable to suppose that when the human occupant
of it moves he will touch or disturb the toad and make him
croak. So I leant over the edge of my berth and waited
for my man to move. He presently rolled over and grunted
in his sleep—an event that was immediately followed by a
croak from the toad. And again; the sound of the moving
followed by the croak. This was past bearing. I lay back .
in helplessness and waited. The two events occurred to-
gether again. I was reduced to such a condition of terror
that I imagined that the reason for which the toad (whose
native haunt was a warm volcanic stream) had left his retreat
under the step, which was very dusty and dry, was to obtain
access to the only source of moisture, the only oasis in the
cabin—my companion’s mouth. In fact, it was only on the
assumption that the toad’s mouth was pressed to my com-
panion’s lips that the immediateness of the response by
croaking to the movement on the part of my friend could
be accounted for. I had only to hear the sequence of grunt
and croak again to be convinced that this was the case.
When it did happen that time I leapt out of my berth, turned
on the light, and looked into my companion’s berth. No
toad was to be seen. I had no doubt that it had escaped
under the clothes when the light was switched on. But I
did not dare to lift up the clothes ever so little, or even touch
them, for I had sufficient sense left to realise that if my
friend woke while I was doing so he would have some difli-
culty in understanding my action if I refused, as I certainly
should have done, to offer an explanation. He did, as a
matter of fact, wake while I was looking at him, and remarked
in a sleepy voice that I seemed rather restless. I admitted
that there was truth in what he said, and clambered up into
my berth. The movement followed by the croak happened
255

i,
An Introduction to a Biology

once or twice again, but there was nothing to be done, and at
last the morning came. On my departure from the ship my
courage failed me, and I did not leave instructions with the
ship’s carpenter. But it may be imagined that I lost no
time in writing to my friend in Naples, telling him of all
this, and asking him whether I had left him one or two
toads, for I knew that I had brought six from Ischia, and
that his answer would settle the question whether or not
I had left the cabin tenanted.

‘In about a week I heard from him. “Set your mind at
rest: you left me two.”

I can, of course, only guess what the noise was. But
the fact that I did not hear it until my companion joined
the ship, a circumstance which I attributed at the time to
the absence of any occasion for the kind of anxiety that I
felt after he had arrived; the fact that I heard it each night
for the first time an hour or so after retiring to rest; the
fact that I first definitely located it under my companion’s
berth and then in it, and, moreover, that it always followed
a movement of restlessness on his part, point to the conclu-
sions that it was effected either gutturally by him or by
a grinding of his teeth.

But the two points I wish you to notice about this are
these. First, that having started with the not unreason-
able idea that a toad had escaped, I spent those long nights
in weighing the value of every possible piece of evidence
that could conceivably bear on it, and in making every possible
experimental test of every interpretation of the phenomenon
that occurred to me; and that the more I weighed evidence
and devised experiment, the less did I question the reality
of the very thing that I was trying to find out. I started
by trying to find out whether a toad had escaped; I ended
by endeavouring to discover what, since it had escaped, it
was actually doing. And if you will look back over the
details of the story, you will see how gradual the transition
from one stage to another was.

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An Introduction to a Biology

And the second point is this. Supposing you start by
postulating the existence of a phenomenon 4, and in order
to find the cause of it cast about for some other phenomenon
with which it is associated. Suppose you find this other
phenomenon B; if A is usually but not invariably associated
with B, you will be fairly satisfied, and will conclude that A
probably exists and that B is probably the cause of A. But
if A is invariably associated with B your satisfaction will be
complete; you will conclude that you have not only estab-
lished the existence of A but determined the cause of it B.
A little reflection about the toad, however, will show you
that you are wrong. Complete association, instead of in-
creasing your sureness, should diminish it. For it shows
that there may be an alternative interpretation—namely,
that there is no such thing as 4, but that what you thought
was A was really B. So you must make some other test ;
if possible a crucial one; and then, maybe, you will dis-
cover that there really was no such thing as A, but that
it was B all the time—as in my case.

Biologists who aim at interpreting things may be classed
under three headings. The classes are arranged in descending
order of bulk and in ascending order of merit. Class I. con-
tains those who do not bother about interpretation at all.
They do it, but they never stop to wonder what they are —
doing. Class II. includes those who bother about it, but
can get no further than accepting the view of one or other
authority as to what they are actually doing. Class III.—
the smallest and the best of all—contains those who have
the desire and the intelligence to find out for themselves what
they really are doing when they are interpreting nature.

You will please conclude, therefore, that what I want
you to do is not to accept my interpretation of inter-
pretation, but to think it out for yourselves. By such
means alone will you be able to reduce to a minimum the
errors which attend the process of interpretation.

We have discussed the sources of error in description

R 257

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An Introduction to a Biology ‘i;

and in interpretation. It now remains to turn our attention
to the relation between those two processes.

At present things are in a very bad way. Hardly any
trustworthy descriptions of things exist. Of course, if we
do not know a thing at all we can find out a great deal by
reading what has been written about it. But if we are engaged
in some investigation, and we desire some definite and final
information on a particular point, we usually end by finding
it much more satisfactory to investigate the point for our-
selves. We usually find that most of the available descrip-
tions are of little value for our purpose. The reason for the
valuelessness of most descriptions is that they fall between
the devil of the interpreter, whose description is spoiled by
his having made it under the intoxicating influence of his
own interpretation, and the deep sea of systematists, who
are not sufficiently interested in interpreting anything to
make their records so thorough that they may be of use
to those who are. We are stranded between the former, who
describe not wisely but too much, and the latter, who describe
not wisely but too little. So we have to determine the point
for ourselves.

, But I would not have you believe from what I have said

that I think it is desirable to eschew interpretation altogether.
It is of course true in biology that we are much less likely
to go wrong if we, confine ourselves to description. But if
we do this we do not get any further; we stagnate. If you
say, “I will go no further than description, on the ground
that it is better to keep on the safe side,” do not be misled
by the meaning of the word “side”; I mean, do not think
that the road leading to the goal of the biologist is like the
Palatine Road, with a safe side and an unsafe one, and that
you can choose on which side you will go. No. The division
is a transverse one; let us imagine it to be opposite the
College. Let us imagine your starting-place to be the Con-
tinental Restaurant, and the goal to be Northenden; the
safe, descriptive side, the town side of the division; and

258

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~ An Introduction to a Biology

the dangerous, explanatory one, the other. If you choose to
keep on the safe side, and confine yourself to description, you
cannot make many mistakes, but you cannot make much pro-
gress ; you cannot go far wrong, but you cannot go far. If you
want to get nearer the goal, you must dare to pass the barri-
cade separating the safe from the dangerous. If you pass
it you stand to lose all by spending your life in going astray,
but you stand to get towards your goal.

It ultimately you do not pass it you will have the com-
pany of Mr. Exclusive Systematist, Mr. Pure Morphologist,

Mr. Collector, and Mr. Nomenclature Specialist—men who .

have never gone astray, all conscious of their blameless past.

But if, tempted by the greater prizes, and careless of
the greater dangers on the other side of the barrier, you
pass it, a very different spectacle will meet your eyes. You
will see Selectionist trudgmg two miles off the track on
the one side, and Mutationist two miles off it on the other ;
and you will hear the former say: “‘ Look at Mutationist ;
he has gone hopelessly astray ; he is four miles off the track.
I am on the high road. Follow me, and you will reach the
goal.” And the latter: “If that isn’t Selectionist ! wan-
dering about, four miles from the main road. I am on the
high road. Follow me, and you will reach the goal.”

But if we ascend to the top of the tower of the College
we can see much more plainly than from down below that
each is the same distance from the road. And I think it
is a good thing sometimes to detach ourselves from our in-
vestigations, and, climbing up into the tower, to try to see
ourselves as objects, looking, from that distance, like ants
on a gravel path; to try to find out what the relation be-
tween ourselves and the things we investigate really is; and
to ask ourselves: “Is the orderliness which we discover in
things really in them; or is it not rather that we classify
things in an orderly way in our mind, and then say, ‘ Lo!
We find order everywhere in Nature!’ ”

_ Yet, although it is pleasant and necessary to retire to
259

4

An Introduction to a Biology

the tower and reflect, if we are to make progress in biology
we must descend to the road. But before we return to our
investigations, let us make certain rules which will keep
us from going astray. Many valuable rules could be made.
But I will suggest only two, which deal with what we have
been discussing this evening. One is: To keep description
absolutely independent of interpretation. The other is: To
remember that what you arrive at by interpreting the thing
you have described is not what you see underneath it, but
what you read into it.

260

Vill

Mendelism

(From the “ Transactions of the Highland and Agricultural
Society of Scotland,” 1913)

MENDELISM is the name given to the method and science of
breeding which has come into existence as the result of the
work of one Gregor Mendel. The history of Mendel’s work
and of its reception is a very curious one. About the middle
of last century he was Abbot of a monastery in Briinn in
Austria ; and in his cloister garden he carried out some hybrid-
isation experiments with the culinary pea, crossing different
varieties with one another and keeping detailed records of the
results. He published his results in the journal of a local
scientific society in 1865. But nobody paid any attention to
his paper, although the facts which he described were of the
greatest interest, and the explanation of these facts which he
put forward was more interesting still. Mendel’s paper lay
hidden and forgotten in the volumes of the Scientific Society
of Briinn from 1865 until 1900, sixteen years after his death,
when it was discovered independently by three botanists—
one in Germany, one in Austria, and one in Holland. As
soon as the attention of the scientific world was drawn to
Mendel’s paper by these three botanists, the great import-
ance of the facts which Mendel had discovered, and of the
theories which he put forward to explain them, was at once
seen. And many investigators set to work to find out whether
the rules which Mendel said applied to his peas applied to
other plants and to animals as well. It is natural that these
investigators should choose as material for their breeding
201

An Introduction to a Biology

experiments plants and animals which multiplied as rapidly
as possible, and could be purchased and bred as cheaply as
possible. And it was reasonable to test the truth of Mendel’s
theory by breeding mice and sweet-peas before applying
it to the improvement of live stock: because it was possible
that Mendel’s rules might only have applied to the material
with which he worked—the culinary pea—and not have
been of general applicability at all. If breeders had started
to apply Mendel’s rules to the improvement of their stock, the
loss of much time and money might have been the result

Thirteen years have now elapsed since Mendel’s papers were

rediscovered, and since the testing of his rules began. And
already it has been found that his rules do apply pretty
accurately to the breeding of a very great number of different
kinds of animals and plants. But these animals and plants
are naturally those which breed rapidly and can be bred

on a large scale at small expense. So it comes about that

our knowledge of the application of Mendel’s rules to the
breeding of horses, cattle, sheep, and pigs is still in its
infancy. The question whether Mendel’s rules do or do
not apply to a particular case can only be decided after a
series of crosses and interbreedings have been carried out
in a particular way, and on a considerable scale: the prac-
tical breeder scarcely ever—in fact, never—carries out his
matings in this way, so that the applicability of Mendel’s
rules to a particular case can never be decided by the ex-
amination of the results of matings not carried out with the
express object of answering this question; though the
results of such matings sometimes give a rough—very rough
—indication of the answer.

Now, Mendel’s rules are so simple that if it could be
shown that those characters of live stock to which especial
attention is paid were inherited in accordance with these
rules, the breeder would be in a position to bring about
great improvements in these characters in a comparatively
short period of time. To bring about these improvements

262

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An Introduction to a Biology

he must know two things: he must know what is the par-
ticular improvement he wants to effect; and this, I assume,
he does know. He must also be familiar with Mendel’s rules ;
and this, I assume, he does not know, or he would not be
reading this article, which is written for those who are not
familiar with Mendel’s work or with the rules which have
been based on that work.

First of all, we will become familiar with the essential
facts discovered by Mendel.

The simplest case, and one that tells us all we want to
know about Mendel’s results, is that of a cross between a.
tall and a dwarf pea. The practical difference between a
tall and a dwarf pea is that tall peas have to be staked and
grown in rows not closer than 6 feet apart, whilst the dwarf
peas do not require staking and can be sown in rows 2 feet
apart. The stumpiness of the dwarf pea is due to the short-
ness of the divisions of the stem between the joints where
the leaves are given off. These divisions in the tall pea are
more than twice as long as they are in the dwarf.

Mendel crossed a tall with a dwarf pea, and found that
the resulting hybrid was in every case tall. It made no
difference whether the tall was used as the male parent and
the dwarf as the female, or the dwarf as the male and
the tall as the female. The resulting hybrids constitute
the first hybrid generation, as shown in Fig. 1.4. Seed is
saved from these hybrids of the first hybrid generation,
which have been allowed to self-fertilise. This seed, when
sown, produces a generation, called the second hybrid genera-
tion, which consists of three talls and one dwarf amongst
every four plants, on the average; or 75 per cent. tall and
25 per cent. dwarf plants. These plants of the second hybrid
generation are again allowed to self-fertilise, and, when they
are ripe, seed is saved from them, This seed, when sown,
produces the third hybrid generation. A look at Fig. 1 shows
that the dwarfs of the second hybrid generation breed true

1 Vide infra, p. 265.
263

An Introduction to a Biology

at once; they produce dwarfs only. Of the three talls in
the second hybrid generation, one, at the left of the diagram,
breeds true; it produces talls only, so it may be called a
pure tall. The two remaining talls—the two in the middle
of the second hybrid generation—each produce talls and
dwarfs in the proportion of 3 to 1—that is to say, they behave,
in their breeding, exactly as do the hybrid talls of the first
hybrid generation, and we may therefore call them hybrid talls.

The facts shown in Fig. 1 may therefore be condensed
into the following diagram :—

Pure Tall x Pure Dwarf

|
Hybrid Tall
|

| |
1 Pure Tall. 2 Hybrid Talls. 1 Pure Dwarf.

Pure Tall x Pure Dwarf
|
Hybrid Tall

|
15% Pure Tall. 50% Hybrid Tall. 25% Pure Dwarf.

We will deal with points to be noticed in Fig. 1 in order
of their importance, beginning with the least important.

It will be seen that the dwarf character entirely dis-
appears in the first hybrid generation. The tall character
completely dominates over it; the tall character is therefore
called the dominant character, and the dwarf character is
called the recessive character. And the two characters, tall-
ness and dwarfness, constitute a Mendelian pair of cha-
racters. I have repeated the word “ character” in the pre-
ceding lines often, in order to lay stress on the fact that
dominance and recessiveness belong to a particular cha-
racter, and not to the plant as a whole.

The second point to be noted in Fig. 1 is that the

264

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An Introduction to a Biology

second hybrid generation is made up of 25 per cent. of plants
like one parent, the pure tall; 25 per cent. of plants like the
other parent, the pure dwarf; and 50 per cent. of plants
like the hybrid of the first hybrid generation. When I say
‘* plants like,” I mean “ like” both in their appearance and
in their breeding properties.

The third point to be noticed is that individuals, in the
second hybrid generation, bearing the recessive character
(dwarfness in this case) breed true; whilst individuals bear-
ing the dominant character (tallness) do not all breed true :
one out of every three, on the average, does; but the re-
maining two produce some dwarf (one in every four plants)
as well. The general rule, which is derived from such a case
as this, is that an individual in the second hybrid genera-
tion which bears the recessive character may be counted
upon to breed absolutely true to that character, at once, 1.e.
before breeding from it. But in the case of an individual
bearing a dominant character, we do not know whether it
will breed true to that character or not until we have bred
from it. The breeding properties of an individual bearing a
recessive character are branded on it in unmistakable letters
directly it appears in the second hybrid generation—PURE.

It is not so with an individual bearing a dominant cha-
racter, which brings us to the last poimt to be noticed. It
is this. Two individuals (in the case before us, two plants
bearing the tall character) may be absolutely identical in
their outward appearance and yet differ profoundly in respect
of the kind of offspring which they will produce. One tall
plant will produce nothing but tall plants. Another tall
plant, indistinguishable from the first, will produce 25 per
cent. dwarfs amongst its progeny. A more striking instance,
which will be explained later, is that of two pairs of white
rose-commbed fowls. One pair will produce nothing but white
rose-combed birds. Another pair, identical in appearance
with the first pair, will produce, besides white rose-combed
birds, white single-combed, black single-combed, and black

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rose-combed birds. The general conclusion derived from
cases such as this is one of the utmost importance in prac-
tical breeding. It is that the appearance of the individual
furnishes no clue as to its breeding properties; and its
ancestry helps just as little. Both the pure and hybrid
talls of the second hybrid generation had precisely the same
ancestry ; and yet the pure produces only talls, and the
hybrid produces dwarfs as well. The individual itself can
tell us nothing of its breeding properties; nor can its an-
cestry. To know how a given animal will breed, we must
breed from it and see. Once we have found that its “ get”.
is good we may be confident that the rest of its offspring will
be up to the same standard. - To estimate the breeding
properties of a given animal we must not look straight in
front of us at the animal himself; we must not look back,
through its pedigree, at its ancestors; all we need to do is
to look forward a little way, one generation in fact, at a fair
sample of its progeny. This is indeed the lesson which |
wish to drive home in this article. And I shall return to
it again when more of the facts have been considered.

We will now take a brief glance at one of the first and
most striking extensions of Mendel’s rules from the vegetable
to the animal kingdom. This is the classical case of the Anda-
lusian fowl. It is a useful case, because it enables us to see in
striking contrast the difference between the Mendelian rules
of breeding and the older rules which the Mendelian rules bid
fair to supplant. The blue Andalusian fowl is characterised
by a beautiful slaty-blue plumage, each feather edged, or
“laced” as it is called, with a darker tinge of the same
colour. If you buy a pen of these blue Andalusians and hatch
the eggs, you will be disappointed to find that only about
half the chicks are like their parents; the remaining half
will consist of black birds and white birds with occasional
blackish feathers. You will probably put this impure breed-
ing down to some recent cross amongst the ancestors of
the birds you bought, and proceed to breed from the blue

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birds which you yourself have bred. With regard to these
you will say, “I, at any rate, know that the parents of these
birds were blue, as I bred them myself.” But you will have
no better luck; the blacks and whites will appear again in
about the same numbers. Still you will say to yourself,
“This black and white impurity looks as if it must have
been introduced very shortly before I bought my birds, so
that perhaps I have no right to expect that all traces of it
will disappear in a paltry two generations. I will con-
tinue to breed from the blues only, always throwing away
the blacks and whites, and ultimately, and I hope before
very long, I am bound to obtain a race of pure-breeding
blues: it stands to reason that if I go on breeding in this
way long enough, I shall at last obtain a pure strain.” Well,
it may stand to reason that it will happen. It won’t happen.
For however many generations the blue Andalusians are
bred together they will produce blacks, blues, and whites in
the following proportions :—

25% Blacks. 50% Blue Andalusians. 25% Whites.

Are not those percentages familiar to us? Do they not
suggest that the blue Andalusian is a hybrid lke the hybrid
tall pea, and that the blacks and the whites are the two
pure forms corresponding to the pure tall and the pure
dwarf? There is a very easy way of finding out if this
supposition is true. If it is true, one of the 25 per cent. blacks
crossed with one of the 25 per cent. whites should give blue
Andalusians only. This is indeed what actually occurs, as
shown in Fig. 2. If this diagram is compared with the
corresponding one for the peas (Fig. 1), the following dif-

ferences will be seen. There is no question of dominance

here; there is no exclusion of one character from the first

generation by the other character. Black and white meet

and compromise in a blue; there is no victory for one of

them, as in the case where tall and dwarf met; so that we
268

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An Introduction to a Biology

have no dominant and recessive characters here. In the
case of the peas, the hybrid and one of the parents—the
tall—were identical in appearance. Here the hybrid has a
character of its own, the blue plumage; so that in the second
hybrid generation we have none of the difficulty which we
had in the peas, of distinguishing between pure talls and
hybrid talls; we see at once which are the parent forms
(the blacks and the whites) and which are the hybrids (the
blues). The hybrid is always blue, and as there are no
blues that are not hybrids, the blues are always hybrids ;
so that it is running one’s head against a stone wall to try
to breed a pure race of blues by continuing to breed from
blues for a great many generations. Yet that is the prin-
ciple on which we should have acted if Mendel had not made
his experiments with peas, or somebody had not discovered
the same thing with other or the same material.

One more point before we proceed to the next case. The
two cases shown respectively in Figs. 1 and 2 differ from
one another in the fact that there is dominance in the first,
and blending in the second. In all other respects they are
identical; in the reappearance of the parent and hybrid
forms in the second hybrid generation ; in the proportions in
which these forms appear; and in their breeding properties.
And the conclusion we draw from this fact is that domin-
ance is not an essential feature of Mendelian inheritance.

A case amongst cattle, exactly comparable to that of
tallness and dwarfness in peas, is that of the absence or
presence of horns. If a cow of a horned breed, such as the
Highland, is served by a bull of a hornless breed, such as
the Aberdeen Angus, all the first crosses will be hornless—
hornlessness being dominant. When these hybrids are
mated together, they will, if there are plenty of them and
they are given time, produce a generation consisting of
three hornless and one horned in every four, on the average.
The horned, since they bear the recessive character, will
breed true at once when mated together; but of the three

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An Introduction to a Biology

hornless, one will be pure breeding and two will be hybrids.
But how are we to tell which are which? In the peas it was
easy enough; peas are hermaphrodite, both sexes being
present in a single flower, so that we could know that in allow-
ing them to self-fertilise we were mating pure with pure or
hybrid with hybrid. But if we took a hornless cow of the
second hybrid generation and a hornless bull, we should not
know with regard to either of them whether the animal was
pure or hybrid. There is, however, a very simple way of
finding out—that is, by mating the hornless animal in ques-
tion with a horned one. If the hornless animal is pure, all its
ofispring by a horned animal will be hornless ; if it is hybrid,
half the offspring will be hornless and half horned. The
general rule is: To find out whether an individual bearing
a dominant character is pure for that dominant character
(i.e. will produce exclusively individuals bearing that domin-
ant character when mated with a similar pure), or is hybrid
for that dominant character (i.e. will produce three in-
dividuals bearing that dominant character, and one indivi-
dual bearing the recessive character in every four on the
average), mate it with an individual bearing the correspond-
ing recessive character. Ii the mdividual was pure, all of
the offspring of such a cross will be individuals bearing the
dominant character; if it was hybrid, half the offspring
will bear the dominant and the remaining half the recessive
character.

A case amongst cattle which is parallel with that of the
Andalusian fowl is afforded by the inheritance of colour
amongst shorthorn cattle. The roan colour has been shown
to be produced by crossing the red with the white. In the
two cases, therefore—the colour of shorthorn cattle and
that of the Andalusian fowl—the red corresponds with the
black, the white with the white, and the roan with the blue
Andalusian. An even closer parallel amongst cattle to the
blue Andalusian is the blue roan, which is produced by cross-
ing black with white. There is a difference, however, be-

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An Introduction to a Biology

tween the two cases—that of the Andalusian fowl and that
of the shorthorn cattle. There is never, so far as my obser-
vations go, any difficulty in distinguishing a black bird from
a blue one; they do not merge into one another by transi-
tional stages; but it is sometimes difficult to say whether
a beast is a red or a roan. There is a curious case referred
to by Prof. James Wilson! to explain how some of the records
in the Herd-Book, which are not in accordance with the
Mendelian interpretation outlined above, may be accounted
for. Most of these are cases of mistaken identification of
colour. ‘‘A bull now standing (1908) at the Albert Agri-
cultural College, Glasnevin, was registered in the Herd-Book
by his breeder, who is the most distinguished breeder in
England, as being red. This bull’s sire was white; his dam
was red; and he ought therefore to be roan. He has bred
several white calves from roan cows; and on this ground
also he ought to be roan. On close inspection he is a roan,
but such a roan as might easily be mistaken for a red.” I
mention this case because it affords a striking illustration
of the change which has been brought about by Mendel’s
work. The old pre-Mendelian system was to estimate how
an animal would breed by looking at it (and its ancestors) ;
if we were breeding for colour we should look at the colour
of the animal in question in order to foretell what its off-
spring would be. But Mendel has completely turned the
tables; and in the case of this bull we had to look at what
his offspring had been in order to tell what colour he was!
The Mendelian doctrine is that the characters of the body
of the animal in question afford a very meagre clue to the
value of that animal as a breeder; the proof of the animal
is in its breeding—that is to say, mn the offspring which it
has proved it can get.

We have so far considered the results which follow when

1“ Mendelian Characters among Shorthorn Cattle.” ‘“‘ Scientific Pro-
ceedings of the Royal Dublin Society,” Vol. 11. (N.S.), No. 28, p. 322.
(June, 1908).

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An Introduction to a Biology

two individuals differing from one another in respect of a
single pair of characters are mated. We have now to con-
sider the results of mating two individuals which differ from
one another in respect of two pairs of characters. This is a
very important case, because on it depends the efficient
carrying out of one of the most important processes of the
breeder—namely, the combination in one strain of char-
acters already existing in separate strains. The behaviour,
on crossing, of two very well-known characters of the fowl
may be used to illustrate this point. The two pairs of cha-
racters will first be considered separately. One pair relates
to the colour of the plumage; and the pair consists of white
and black, white being dominant over black. The other pair
relates to the shape of the comb, and consists of the so-called
“rose”’-comb (of Wyandottes and Hamburghs) and the
single comb (of Minorcas and Leghorns) of which the “ rose ”
is dominant over single. Let us now describe an actual case
in which these two pairs of characters are concerned. Such
a case 1s a cross between the Black Hamburgh, which, as its
name implies, is black, and like all the Hamburghs has a
rose-comb, and the White Leghorn, which is white, and has
a single comb as shown, very diagrammatically, in Fig. 3.
White being dominant over black and “rose” over single,
the hybrid produced by crossing the parent forms described
above should have white plumage and a rose-comb, and it
actually has. I bred many such hybrids last year. In pass-
ing, it may be remarked that this result shows very clearly
the profound difference between dominance and a thing to
which the name “ prepotency ” has been given. A prepotent
animal is one which is supposed to have the power of impress-
ing its characteristics on all its offspring, whatever it is
mated with. It is usually a particular stallion or bull which
acquires the reputation of prepotency. This prepotency is
supposed to be due to the exceptionally great constitutional
vigour of the prepotent animal, a vigour which has no diffi-
culty in overcoming the feeble opposition offered by the
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An Introduction to a Biology

inferior vigour of its mate, and in impressing its charac-
teristics in their entirety on their offspring. It might be
thought that a tall pea dominates over a dwarf pea because
the tall has greater constitutional vigour. But, as I have
already pointed out, this is not the case. Dominance and
recessiveness belong not to the individual as a whole, but
to the distinct characters of the individual. We could not
prove this to be so in the case of crosses between individuals
differing in respect of a single pair of characters only; but
we can prove it up to the hilt in the present case of a cross
between two individuals differing from one another in respect
of two pairs of characters—the shape of the comb and the
colour of the plumage. Of the two dominant characters
shown by the hybrid, rose-comb and white plumage, one
comes from the Black Hamburgh and the other comes from
the White Leghorn. So there is no question here of one of
the parents impressing its characters as a whole on its off-
spring. The reason that the Black Hamburgh transmits its
rose-comb to the hybrid cannot be because it has greater
constitutional vigour than the White Leghorn, because the
Black Hamburgh fails to transmit its black plumage. Simi-
larly, the ability of the White Leghorn to transmit its
white plumage to the hybrid cannot be due to its greater
constitutional vigour, because it cannot transmit its single
comb.

You may say, if you like, that the Black Hamburgh was
prepotent with regard to its comb, and the White Leghorn
with regard to its colour; but if you do you are merely
expressing the Mendelian idea of dominance in terms of pre-
potency. The truth is that dominance has nothing to do
with the individual at all; it relates solely to the separate
characters which we can deal with in breeding—colour of
plumage, shape of comb, etc.; and this brings us to the
very essence of the Mendelian doctrine, which is, that im a
scientific principle of breeding, attention must be paid not
to the individual as a whole, but to its various characters,

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An Introduction to a Biology

which can be shown to be inherited independently of one
another. i

We shall see what this means if we observe what happens
when the white, rose-combed hybrids, between the Black
Hamburgh and White Leghorn, are mated together. If a
sufficiently large number of chicks is hatched out we shall
find all the four possible combinations of the two pairs of
characters, white and black plumage, and rose and single
comb, in the order shown in the diagram, Fig. 3; and in the
proportions indicated—9 white, rose; 3 black, rose; 3
white, single; and 1 black, single. The numbers indicate
the average number of each combination in every 16 birds ;
but, of course, there would have to be many more than 16
birds to get anything like a close approximation to these
actual proportions. But the proportions are not the essen-
tial fact, though they are very important. The essential
fact is that all possible combinations of the characters borne
by the parents do occur in the second hybrid generation.
This reveals an important fact and teaches an important
practical lesson. The fact which it reveals is that the shape
of the comb and the colour of the plumage of, for instance, the
Black Hamburgh, are not transmitted in conjunction, but
can be separated from one another by cross-breeding, so
that, for instance, the black plumage of the Black Hamburgh
can be taken up as an independent element and united with
the single comb of the White Leghorn, and be permanently
combined as in the last bird on the right at the bottom of
Fig. 3. The principle of recombining characters in breed-
ing is of course not a new one—it must have been done un-
consciously, and has probably been done deliberately ; but
a familiarity with the simple scheme given in Fig. 3 will
greatly facilitate the process of the recombination of cha-
racters.

The important lesson to be learnt from the fact that all
possible combinations of the parental characters occur in the
second hybrid generation we are considering, is that this

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An Introduction to a Biology

total possible number of combinations occurs when the first
crosses are mated together and in no other way. Suppose
the cross between the Black Hamburgh and the White Leg-
horn had been made with a view to get a black fowl with a
single comb, nothing could have been more disappointing
than the first cross—a white fowl with a rose-comb, a fowl
which exhibits neither of the characters it was wished to
combine. What the breeder would probably do under such
circumstances would be to mate the hybrid back with one
of the parents “‘ to put in some more of the required blood.”
The last thing he would have dreamt of doing would be to.
mate together his two first crosses, which showed neither
of the two characters he wished to combine. Yet this is
the only mating which would give him the desired combina-
tion—black plumage with single comb. The reason that
he would not think of mating together the two first crosses
is that he was under the influence of the old error of regard-
ing the visible bodily characters of an individual as an indi-
cation of its breeding properties. And the reason why he
would mate the first cross back with one of the parent forms
would be the same. But the fact is that, especially in the
case of hybrids, the appearance of the animal gives no clue
whatsoever as to what it is likely to produce. And matters
are often much worse than in the case of poultry which we
have described. The hybrid very often, as is well known,
does not, as in the case just described, exhibit the characters
of either of the parents, but of some supposed remote wild
ancestor. Nothing could be more disappointing than the
production of such a scarecrow by crossing two valuable
animals of two different sorts; and nothing is more certain
than that the breeder would not breed more of them in order
to obtain a male and a female to mate together. Never-
theless, this is what, according to the Mendelian doctrine,
he ought most unquestionably to do. Indeed, I would even
go so far as to suggest this possibility, that the less the first
cross approximates to the result which the breeder expected
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An Introduction to a Biology

to ensue from the cross, the more worth while will it be to
mate these first crosses together. But I do not press this
point. All I am concerned to insist on now is that if the
immediate result of a cross is far from what was expected,
this should not be cause for disappointment. If any valu-
able new combination of characters is to come out of a
particular cross, it is not to be expected till the second hybrid
generation.

For instance, I have made some crosses between Jersey
and Ayrshire cattle with the view of finding out whether a
cow can be raised which has as high a percentage of butter-
fat in its milk as the Jersey, and gives as great a quantity
of milk as the Ayrshire, or at any rate approaches to this
ideal. I am prepared to find that the cows of the first hybrid
generation are even inferior to both the parent breeds in the
quality and quantity of their milk. But this would not make
me less sanguine in the hope that some cow “ of noble note
may yet be” bred in the second hybrid generation. If the
two characters which I wished to combine—high yield and
high butter-fat percentage—were recessive ones, the desired
combination would only occur once in every sixteen indivi-
duals. But I do not anticipate that either yield or butter-
fat percentage will exhibit simple dominance. Indeed, in
other crosses of this kind, as between the Jersey and the
Danish for example, it is known that, so far as butter-fat
percentage is concerned, the first cross between these two
breeds is a blend between the two parental percentages.
In the second hybrid generation, therefore, we must not
expect four sharply circumscribed classes as in the case of
Fig. 3, but a very wide range of classes, all of which
merge into one another—a very wide range of classes
(merging into one another) with regard to butter-fat
percentage, ranging from the high to the low, and a similar
range of classes with regard to quality. It simply remains
to be seen whether there can coexist in one cow the
high yield of the Ayrshire and the high butter-fat per-

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An Introduction to a Biology

centage of the Jersey. And it will take many years to
find out.

It may have occurred to the reader to object that the
immediate result of a cross is not by any means always dis-
appointing. Of this fact I am well aware. But the value
of such crosses is usually due to the fact that first crosses
commonly possess great strength, health, and vigour, and
is not due to the combination of deliberately chosen desir-
able characteristics, which is the subject under discussion.
The best bacon, I believe, is produced by first-cross swine :
and the same general truth obtains in the case of other stock
as well. But the exceptional value of these first crosses must
be distinguished carefully from the value belonging to new
combinations of characters. The exceptional value of first
crosses is due to the fact that they are first crosses; they
have this exceptional vigour and robustness, in virtue solely
of the fact that they are first crosses; and they would not
hand it on to their offspring if they were mated together.
The value of such first crosses is a flash in the pan. But the
value of a new combination of characters brought about in
the second hybrid generation has no more to do with the
animals being hybrid than the fact that it was necessary to
make a cross to bring the characters together. But once
these characters have been re-combined in a few individuals
and made the foundation of a breed, this particular combina-
tion has a value so long as the need which called it into exist-
ence persists.

In conclusion, let me repeat the central idea in this
article: that neither the characters of the individual itself
nor of its ancestors gives any indication of the value of that
individual as a stock-getter. A few records of the milk-
production of the daughters of an Ayrshire bull are of much
greater use as an indication of his value than all the avail-
able information with regard to his dam and granddams.
You cannot tell what the breeding properties of a beast
are until you have tested them. You cannot say whether

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An Introduction to a Biology

a goose will lay golden eggs or not until it has begun
to lay. ¢

This article is intended merely as an introduction to the
subject. The most elementary treatise on it is ‘‘ Breeding
and the Mendelian Discovery ”’ (Cassell and Co.), by the
present writer. An excellent account of the whole subject
of Heredity is given in J. A. 8S. Watson’s “ Heredity ” (the
People’s Books series). For fuller information on the sub-
ject of Mendelian Heredity the reader is referred to R. C.
Punnett’s “‘ Mendelism” (Macmillan and Co.); and for
an exhaustive treatment of the whole subject to Bateson’s
classical work, ‘“‘ Mendel’s Principles of Heredity” (Cam-
bridge University Press).

280

|

Francis Galton!

A GREAT personality has passed from us in the death of
Francis Galton. To few has it been given to live so full and
so valuable a life. The Goddess Fortune, it is true, offered
him opportunity with a generous hand; rarely, however,
has an offer been more amply justified than that she made
to Francis Galton, for the treasure has been invested by
its trustee in safe things, which will never cease to pay.
Galton never flew too high nor attempted to probe too deep ;
he was conscious both of the extent and of the limitation of
his powers ; his work is of lasting value to mankind because
he possessed in a high degree that sense which tells its owner
which tasks lie within and which beyond his power.

But we should be disloyal to Galton if we regarded him
as an isolated personality detached from his natural setting
—his ancestry. Indeed, we are not truly loyal to what he
believed unless we regard the individual as a product (in
the strictly literal sense of a continuation without cessation
of individuality) of his ancestors, and intelligible only in the
light of a knowledge of those ancestors. Turgenev and
Samuel Butler owe their supreme position as novelists to the
fact that they perceived this.

Perhaps the most remarkable instance of a monopoly
possessed by a single family over a particular business is
the limitation to the Darwin family of the business of bring-
ing home the truth of evolution to the understanding of
mankind. We make no apology for the term business. It
is no longer necessary to point out that Charles Darwin’s
achievement was not to discover evolution, but the much

1 Obituary notice in Science Progress, 1911.
g* 28%

An Introduction to a Biology

heavier task of forcing mankind to believe in it. To satisfy
oneself of the truth of evolution is the work of a philosopher ;
to convince other people of this truth is a labour of Hercules.

Erasmus Darwin married twice. By his first wife he was
grandfather to Charles Darwin, by his second to Francis
Galton. ‘‘ His hereditary influence,” says Galton (“‘ Memories
of My Life,” p. 7), “‘seems to have been very strong. His
son Charles, who died at the early age of twenty of a dis-
section wound, was a medical student of extraordinary pro-
mise.” Erasmus may not have been—probably was not—
the first to perceive the fact of evolution ; there can be little
doubt that Buffon was before him. But with Erasmus
Darwin the business of making evolution credible passed
over once and for all to the “nation of shopkeepers” and
the Darwin family. Not only was Erasmus Darwin’s enun-
ciation of the doctrine of evolution less equivocal than
Buffon’s (through no fault of the latter, however), but the
sudden conversion of Lamarck, late in life, to a belief in
evolution followed so closely after the appearance of a French
translation of “‘ The Loves of the Plants” by E. Darwin,
as to leave little room for doubt that the two events were
causally connected. Of Charles Darwin’s participation in
the task of making evolution credible no more need be said.

We must now turn to the part played by his cousin.
Galton, by laying the foundation of an exact science of
heredity, not only took steps to fill in the most serious gap
in the evolutionary hypothesis, but sowed the seed of a
tree which will furnish the best, if not the only, antidote
to that outbreak of a priors speculation which followed the
publication of the “ Origin.” Galton’s vivid perception of
the necessity of having things surely and certainly described
before any attempt was made to explain them, found its
expression in the application of statistical methods to the
study of biological problems. It was not only by that part
of his work which laid the foundations of Biometry that
Galton supplemented the work of Darwin; he also drove

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An Introduction to a Biology

home the applicability of our knowledge (such as it is) of
evolution and heredity to the furtherance of human welfare,
and thus laid the foundations of the science of Eugenics.

Galton’s greatest work in the purely scientific sphere
must be regarded as the foundation of the Biometric method
and philosophy rather than the promulgation of the law
of heredity which is associated with his name. This law,
which was deduced from a study of Basset-hound pedigrees,
will in the future be remembered, not so much as a true
summary of a vital process, but as the expression of a first
valiant attempt to detect some order in the chaos of here-
ditary phenomena as they appeared at the time. Its purely
provisional nature is foreshadowed by the fact that its author
did not commit himself to a dogmatic statement on the ques-
tion whether it was applicable to the individual or to the
mass, and demonstrated by the fact that only in rare, prob-
ably accidental, cases does it apply to masses, and that in
no case does it apply to individuals. Galton’s work on
Basset-hounds will always be remembered for the same
reason as will de Vries’s work on “ The Evening Primrose,”
estimating both of these at their lowest possible valuation.
Both were the first attempts to break the ground in a new
field of evolutionary inquiry. The pioneer nature of Galton’s
work in heredity is gracefully and fittingly acknowledged by
Johannsen, whose “ Erblichkeit in Populationen und in reinen
Linien,”’ which represents the most recent and ingenious
attempt to interpret a certain class of hereditary phenomena,
is dedicated to him.

No account of Galton would be complete without refer-
ence to his work on Finger Prints. The source of his interest
in this subject was delight in the observation and systematisa-
tion of the phenomena themselves; their application was a
subsequent matter. His interest in them arose through a
request to deliver a Friday evening lecture on the system
“devised by M. Alphonse Bertillon for identifying persons
by the measurements of their bodily dimensions.” Galton

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An Introduction to a Biology

tried to persuade M. Bertillon to incorporate finger prints
into his system of identification, but without success. He
found, however, that they had already been employed by
Sir William Herschel in his district in India, who succeeded
in introducing them into Bengal and subsequently through-
out the whole of India. At the present day there are few
civilised countries in which they are not employed for the
purposes of the identification of criminals. Galton’s hopes
that finger prints would prove to be of high anthropological
significance were not fulfilled. He was unable to find that
any particular type is characteristic of members of widely
divergent human races; or of such widely different types
within a single race as “students of science, students of
art, Quakers, notabilities of various kinds and a considerable
number of idiots at EHarlswood Asylum.” Only one result
of positive theoretical significance emerged from this study :
this was the demonstration that the variation of the pattern
was of the discontinuous kind, and the conclusion that the
various types had been evolved without the aid of natural
selection.

It is @ curious coincidence—if indeed it be a coincidence—
that the respective founders of two great schools of heredity,
the Biometric and the Mendelian, were born in the same year.
Galton and Mendel were both born in 1822. Galton (“ Mem-
ories of My Life,” p. 308), with characteristic courtesy, refers
to Mendel’s work immediately before he refers to his own
law. His estimate of the significance of the work done
and inspired by Mendel seems to us to be so true and con-
cise that we make no apology for quoting it together with
the rest of the paragraph in which it occurs: “I must stop
for a moment to pay a tribute to the memory of Mendel, with
whom I sentimentally feel myself connected, owing to our
having been born the same year, 1822. His careful and long-
continued experiments show how much can be performed
by those who, like him and Charles Darwin, never or hardly
ever leave their homes, and again how much might be done

284

An Introduction to a Biology

in a fixed laboratory after a uniform tradition of work has
been established. Mendel clearly showed that there were
such things as alternative atomic characters of equal po-
tency in descent. How far characters generally may be
due to simple, or to molecular characters more or less
correlated together, has yet to be discovered.” The grace
and simplicity of this, the delicate manner in which Mendel
is associated with Charles Darwin and the soundness of the
critical estimation are very characteristic of Galton. It is
often said that the course of Charles Darwin’s work and
thought would have been very different if Mendel’s work.
had come under his notice. It is curious to speculate as
to what might have been the course of hereditary inquiry
if Galton himself had made the experiments actually carried
out by Mendel.

Galton’s claim to fame, however, does not rest only on
his pioneer work in the investigation of heredity. He will
be perhaps longer known, and he is at present more widely
known, as the champion of the application of such know-
ledge of heredity as we possess to the improvement of the
human race; in other words, as the founder of Eugenics.

His interest in this question first found expression in two
articles on “ Hereditary Talent and Character,’ published
in Macmillan’s Magazine in 1865, which, curiously enough,
is the year in which Mendel published the results of his own
classical researches. The width of Galton’s interests at this
time may be gathered from the fact that the publication
which preceded this was one on “ Spectacles for Divers, and
the Vision of Amphibious Animals,” the one which succeeded
it being that on the “‘ Conversion of Wind-charts into Passage-
charts.” But the actual investigation of the problem of
race improvement was laid aside for many years because
he felt that “popular feeling was not then ripe to accept
even the elementary truths of hereditary talent and char-
acter upon which the possibility of Race Improvement de-
pends.” Moreover, he himself was “too much disposed to

285

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An Introduction to a Biology

think of marriage under some regulation and not enough —
of the effects of self-interest and of social and religious senti-
ment.” The term Eugenics was first applied by Galton to
the scientific attempt to ameliorate the human race in his
‘“ Human Faculty,’ which appeared in 1883 ; and his interest
and inquiries up to date were gathered up into his “ Huxley
Lecture ’’ before the Anthropological Institute in 1901 on
the “ Possible Improvement of the Human Breed under
the existing conditions of Law and Sentiment.”

The active prosecution of eugenic inquiry has been handed
over to the professed representatives of the Biometric school.
How this has been done may best be told in Galton’s own
simple words. After referring to the foundation by Professor
Karl Pearson of a Biometric laboratory in University College
and the institution of Biometrika and his connection with
it as Consulting Editor, he says (“ Memories of My Life,”
p. 320), “ The ground had thus become more or less prepared
for further advance; so after talking over matters with the
authorities of the University of London and obtaining their
ready concurrence, I supplied sufficient funds to allow of
a small establishment for the furtherance of Eugenics. The
University provided rooms and gave the sanction of their
name and various facilities, and I provided for a Research
Fellow and a Research Scholar. The Eugenics laboratory of
the University of London is now situated in University
College, in connection with Professor Karl Pearson’s Bio-
metric laboratory, and I am glad to say he has consented
to take it for the present at least under his very able super-
intendence ; as I am too old and infirm to look properly
after it.’ Eugenics, it may be well to remind the reader
at this point, is officially defined in the minutes of the Uni-
versity of London as ‘“‘ The study of agencies under social
control that may improve or impair the racial qualities of
future generations either physically or morally.”

The actual investigation of eugenic problems is thus
cared for. But there has also sprung into existence the

286

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An Introduction to a Biology

- Eugenics Education Society, which acts the part of a middle
man whose function is to exhibit the results of those investi-
gations so that they shall be intelligible and palatable to the
lay mind.

The institution of the eugenic movement was evidently
regarded by Galton as his life-work, for he concludes his
autobiography with a restatement of his views concerning
it. “I take Eugenics very seriously, feeling that its prin-
ciples ought to become one of the dominant motives in a
civilised nation, much as if they were one of its religious
tenets.” Here is a life-work of which any man might well -
be proud.

Galton practised the principles which he preached in
his marriage with the daughter of Dr. Butler, for many years
Headmaster of Harrow and then Dean of Peterborough.
Dr. Butler was not merely an able classicist and mathema-
tician himself, but transmitted his qualities in full measure
to his children and grandchildren. The remarks which
follow the reference to his marriage and to his wife’s family
are perhaps the most interesting, because the most intimate,
of his eugenic pronouncements.

i . The Butler family well deserve study as an
instance of hereditary gifts, but this is hardly the place
for it.

“Neither can I enlarge as I could have done on the far
greater importance of being married into a family that is
good in character, in health and in ability, than into one
that is either very wealthy or very noble but lacks these
primary qualifications. . .

“I protest against the opinions of those sentimental
people who think that marriage concerns only the two prin-
cipals ; it has in reality the wider effect of an alliance between
each of them and a new family.”

It is a happy circumstance that Galton lived long enough
to complete that vivid and detailed picture of himself,
“Memories of My Life.” This is by no means a piece of

287

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of i

y
a

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=? <.
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An Introduction to a Biology

elaborate self-analysis. The picture presented to us of the
author is conveyed by his own simple unaffected style and
seen in the mirror of his varied environment. The dominant
note in Galton’s personality was his simplicity ; to the last
he preserved a childlike delight in trivialities which is an
attribute of only very great men. His delight at having a
genus of plants related to the Hyacinths named after him
was unbounded, and we cannot but be deeply moved by
the little drawing of Galtonia candicans which concludes
his autobiography.

Perhaps the most beneficent symptom of Galton’s peren-
nial youth was the sympathy which he felt and delighted
to express with those who were beginning. There are, to
our own personal knowledge, many men who have not yet
attained to half the age at which Galton died, and who have
done and will do work of the highest scientific value (in the
most literal sense of the word scientific), whose greatest
and in some cases only encouragement has been a kind word
or line from the great man whose death has deprived them
of a true friend and science of a noble servant.

288

a SS

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“On the Result of Crossing Japanese Waltzing with Albino
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Review of Second Edition. Nature, January 17, 1907.
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Nature, December 7, 1905.
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