INCT

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ENCE

EDICAL

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INSTINCT AND INTELLIGENCE

PUBLISHED BY THE JOINT COMMITTEE OF

HENRY FROWDE AND HODDER & STOUGHTON

AT THE OXFORD PRESS WAREHOUSE

FALCON SQUARE, LONDON, E.G.

INSTINCT AND
INTELLIGENCE

N. CrMACNAMARA. F.R.C.S.

LONDON:

HENRY FROWDE HODDER & STOUGHTON

Oxford University Press Warwick Square, E.G.

1915

,

BY THE SAME AUTHOR.

HUMAN SPEECH. KEGAN PAUL & Co.

THE ORIGIN AND CHARACTER OF THE BRITISH
PEOPLE. SMITH, ELDER & Co.

THE HUNTERIAN ORATION FOR 1901.

SMITH, ELDER & Co.

THE STORY OF AN IRISH SEPT. J. DENT & Co.

THE HISTORY OF ASIATIC CHOLERA.

MACMILLAN & Co.

PREFACE

THE meaning of the term Education is " to
draw out what is in a child " ; it therefore in-
cludes the training of his inherited instinctive
disposition or character, as well as the " putting
in" needful knowledge, or the "instruction"
of his intellectual faculties. Educationists of
the present time appear to exaggerate the im-
portance of training the intellect, and are apt
to overlook the fact that each individual pos-
sesses certain instinctive qualities which to a
large extent determine his behaviour through-
out life. These qualities, which no human
power can eradicate, mayy however, be favour-
ably modified by appropriate training.
v\\ In the following pages we have endeavoured
to give an outline of the evidence, and the
reasons upon which we rely to prove that the
instinctive behaviour of human beings depends

vi Preface

on work performed by definite parts of the
brain; consequently, education has not only to
deal with the training of something immaterial
which we call mind or consciousness, but has
first and foremost to deal with the proper de-
velopment of the nervous substance of that part
of the brain the orderly working of which is
essential for the occurrence of instinctive, and
intellectual phenomena. In the majority of
healthy children this purpose can be attained by
means of the appropriate exercise of their eyes,
ears, and other sensory organs; for, as we ex-
plain, energy derived from this source stimu-
lates and develops the living substance of those
parts of the brain directly concerned in the
elaboration of an individual's instinctive and
intellectual processes; we may thus hope to
lay the foundation on which to build up a
chaste, self-reliant character combined with a
clear and strong intellectual capacity.

CONTENTS

I'AGE

CHAPTER I.

Molecules and Atoms — Energy free and potential — Proto-
plasm as a transformer of energy — Food — The brain as
a transformer of energy — Instinct and reason — Sydney
Smith — Definition of Instinct — The Amoeba — The Vol-
vocinae — Memory and Instinct ..... 9-30

CHAPTER II.

Multicellular animals — Sex — Hydromedusae — Hydra — Appear-
ance of nerve cells — Medusoids — Their nervous system —
" Eye-spots " — Purposive movements of Hydra according
to stimulus — Purposive movements of Medusoids de-
pendent on existence of nervous system — Purposive
movements of unicellular organisms accounted for —
Development of sensory organs — Light as stimulus . 31-56

CHAPTER III.

The nervous system of the Star-fish — Purposive movements
dependent on presence of sensory organs — Development
of head in animals — Earth-worms — Rudimentary brain —
Hereditary instinctive movements — Crayfish — Increased
complexity of brain corresponding to higher order of
instinctive movements — Labyrinth experiments — The
brain of insects — Their sensory organs — Highly de-
veloped instinctive processes in Ants, etc. — Automatic
processes 57~93

CHAPTER IV.

Nerve cells and nerves — Spinal cord — Motor and sensory
nerves — Reflex action — The brain — The Amphioxus and
its nervous system — Fish — The Lamprey and its brain —
The basal or instinctive ganglia — The development of
the cerebral cortex — The Mud-fish — The Stickleback,
Salmon, Perch, instinctive processes of, shown in traits
of character — Their existence depends on presence of
basal ganglia — Amphibians, brain of — Location of centre
of instinctive movement — Reptiles, sense organs of —

Birds 94-124

vii

viii Contents

CHAPTER V.

The Neopallium in Mammalia, extinct and surviving — The
Tasmanian Devil — The Duckbill — Release of energy in
response to stimuli — The folds of the Mammalian
brain — The functions of the cortex — Cortical areas —
Intelligence in dogs — Macaques — Areas of Neopallium —
Learning by imitation — Baboons — Limits of intelligent
action 125-138

CHAPTER VI.

The hereditary qualities of the Neopallium and basal ganglia
contrasted — the brain of Tertiary man — The brain of
a microcephalous idiot — The arrest of human intel-
ligence when sense organs are absent — Education
through a single sense organ — Association nervous
centres — The modus operandi of a sensation — Memory
and sensation — Ideas and impressions — The mechanism
of reading — Sensory cortical centres .... 139-164

CHAPTER VII.

The cerebral cortex and insanity — The inherited instinctive
powers of the new-born — Development of cerebral hemi-
spheres and formation of conceptions of space, etc., due
to stimulation from without — The nervous element in
reflex action — Acquired reflexes — Their seat in the Neo-
pallium— Development of this and basal ganglia the
physical basis of education — Hereditary development
of basal ganglia cells — Emotional expression in children
born blind and deaf — Heredity in an Andaman tracker —
Hereditary qualities capable of being modified — Train-
ing of animals — Instinctive qualities to be cultivated or
repressed — Instinct usually more to be relied on than
intellect — Early training essential — Free play to chil-
dren's actions advocated — Training of association areas
of the brain — The Montessori system — Misdirected educa-
tion of to-day — Aim of education — Classification of
pupils — Cadet courses with technical training . . 165-202

APPENDIX.

The origin of structural variations in living organisms, and

their adaptability to the environment .... 203-213

INSTINCT AND INTELLIGENCE

CHAPTER I

Molecules and Atoms — Energy free and potential —
Protoplasm as a transformer of energy — Food —
The brain as a transformer of energy — Instinct
and reason — Sydney Smith — Definition of Instinct
—The Amoeba — The Volvocinae— Memory and
Instinct.

IN the following pages we shall frequently have
to refer to the molecules and atoms constituting
the basic substance of living matter. It may be
well, therefore, to define the meaning we attach
to these terms. Let us suppose we proceed to
subdivide a drop of water into its smallest con-
ceivable particles, we should in time come on a
single unit particle, or molecule of water, the
smallest particle of water that can exist. It
could not properly be described as the atom of
water, because, although it represented the limit

io Instinct and Intelligence

of conceivable mechanical subdivision, it can
be decomposed into its constituent elements-
hydrogen and oxygen. The word molecule is
thus employed to represent the smallest single
particle of any substance, whether elementary
or compound that has a separate existence;
whilst the word atom denotes a constituent ele-
mentary particle of a molecule.1 Atoms are
now held to consist of a central nucleus around
which multitudes of electrons constantly re-
volve.2 The structural arrangement and motion
of atom-clusters are all important as being the
directing agents of the kind of work performed
by various kinds of matter. For instance, the
molecules of the two substances known as
benzonitrile and phenylisocyanide each contain
seven atoms of carbon, five of hydrogen, and
one of nitrogen. There is a small difference in
the arrangement of the atoms of these two sub-
stances, and this slight difference in their atomic

1 Matter and Energy, by Frederick Soddy, F.R.S., p. 48.

2 " Electrons have been described as immaterial in the sense that
they arc not matter, but something at once finer grained and
endowed with fundamental qualities which distinguish them from
any known kind of matter ; they revolve thousands of millions of
millions of times per second, so that it might be supposed impos-
sible to measure the electron ; but as a matter of fact no magni-
tudes in science are known with greater exactitude." — Matter and
Energy, pp. 170, 175, 187.

Molecules and Atoms n

architecture completely alters their character,
one being a harmless aromatic fluid, the other
an offensive poison.

Atoms and molecules are far too small to be
seen under the highest powers of the micro-
scope ; nevertheless, their size and the velocity
of their movements are accurately known. We
may perhaps form some mental picture of their
movements, by watching the perpetual motion
of inorganic particles seen in a drop of turbid
water when placed under a good lens. Hour
after hour these particles may be seen to be in
a lively state of movement; each particle con-
tains millions of molecules and infinitely more
atoms, all of which are in constant motion
similar to that observed in the drop of
water.

But we know that one of the fundamental
properties of matter is its inertia; that is, its
disinclination to move when at rest, and to stop
moving after it has once been started. What,
then, is the cause of the constant motion of
atoms and molecules? In answer to this ques-
tion we reply " energy " is the cause of all these
and every other kind of movement ; as Professor

12 Instinct and Intelligence

Soddy remarks, before any object can start,
what we call " energy must be supplied to the
matter, and before it can stop this energy must
be taken from it." l

At present it is an open question as to whether
energy possesses an atomic character; like
matter, we know it is conserved, and what is
conserved has physical existence ; in other
words, when energy appears it must come from
somewhere, and when it disappears it must go
somewhere. Energy has been defined as that
which has the power of changing the properties
of bodies ; it is the cause, change of condition
the effect, " the capacity for doing work." For
instance, to keep a grindstone in motion a cer-
tain amount of, say, muscular energy must be
expended to overcome the resistance opposed
by the air, axle bearings, etc. If a piece of steel
is pressed against the stone while in motion the
steel soon becomes warm. If a vulcanite tyre
be placed on the grindstone, and the rim
pressed with a piece of flannel electricity will be
developed, which can be reconverted back into
mechanical motion. Heat and electricity are

1 Matter and Energy, by F. Soddy, pp. 19, 78, 91, 171.

Conservation of Energy 13

well-known concomitants of chemical action.
Hence we infer that heat, electricity, mechanical
motion, and chemical action are a few among
many other different kinds of one distinct
entity-energy.1

Observation has shown :—

I. That one form of energy can be trans-
formed directly or by intermediate steps into
any other form.2

II. When any quantity of one form of
energy is made to disappear, an equivalent
quantity of another form or forms of energy
reappear.

III. We recognise energy in two forms :
Kinetic free or available, and Potential or
possible energy; the first depends on motion,
the second on the position of the body under
consideration. Thus, when a marble is set roll-
ing, it has the power in virtue of its motion of
changing the state of motion of any other

1 Text Books of Physical Chemistry, edited by Sir William
Ramsay. Volume on Chemical Statics ana Dynamics, by J. W.
Mellor, D.Sc., p. 21.

2 "The mechanism by means of which stimulating waves are
converted into heat in the body acted on is still a mystery. That
waves should cause the electrons to vibrat- is perfectly clear, but
how vibrations of the electrons are converted into those vibrations
of the atonu and molecule - which constitute heat is still unsolved."
— P. Phillips on Radiation, p. 57.

14 Instinct and Intelligence

marble which it might strike; it therefore pos-
sesses kinetic or free energy in virtue of its
motion or active condition.

Potential energy, on the other hand, is asso-
ciated with a body in virtue of its position.
Thus, when a stone is lifted above the ground,
the energy expended and the work done in lift-
ing it are measurable quantities of energy stored
up or rendered passive in some way, and this
energy can be recovered or set free in a measur-
able form. Coal represents an accumulation of
light and heat energy derived by plants in by-
gone ages from the sun, which has been trans-
formed by means of the living basic substance
of these plants into chemical energy. In order
to liberate this potential or latent energy another
chemical substance in the shape of oxygen is
required, which acts on the molecular structure
of the coal and sets its latent energy free in the
form of heat, light, etc.

We have given an example (p. 10) of a
change in the arrangement of the atoms in an
organic substance which completely alters the
character of the work it performs ; the same rule
holds good for inorganic matter. For instance,

Conservation of Energy 15

the structural arrangement and motion of the
elements which form a piece of iron wire is such,
that they can act as a means of transmuting
magnetic energy into electrical or into mechani-
cal energy. A thread of platinum is so sensitive
that it reacts by a variation of electric conduc-
tivity when struck by a ray of light of so feeble
an intensity, that it can produce an elevation of
temperature amounting to only one hundred-
millionth of a degree. Hertzian waves which
have travelled over hundreds of miles, and are
therefore extremely feeble, nevertheless so
modify the structure of the metal they reach
as to produce marked changes in its electric
conductivity. Again, it has been shown that
metals become for a time less sensitive after
constant excitation, but regain their irritability
after an interval of repose ; while their peculiar
qualities may be excited or depressed or even
abolished by chemical substances.1

The structural arrangement of the molecules
which constitute the basic substance of living
protoplasm makes it peculiarly sensitive to

1 Annual Report of the Smithsonian Institution for 1903, p. 288.
Also Human Speech, by N. C. Macnamara, p. 13.

1 6 Instinct and Intelligence

energy changes, and thus capable of taking up
energy in one form and transmuting it readily
into another. For example, when a healthy
plant is excluded from that form of energy
which we call sunlight, its green leaves lose
their colour, but if this plant is removed into the
light the protoplasmic elements of some of its
cells undergo changes which result in the re-
appearance of the natural green colour of the
leaves.1 This colouring matter is contained in
what are known as chlorophyll bodies or cor-
puscles, the basic substance of which is derived
from the living matter of the protoplasm of the
cell in which the chlorophyll appears. Our
chief interest in these green corpuscles is, their
elements are so arranged that they act as
specialised energy-transformers. Chlorophyll
corpuscles if treated with alcohol soon lose their
green colour; the chlorophyll being dissolved
out of them by the alcohol, there remains a
colourless corpuscle which gives the reaction of
proteid substance, and is doubtless of a proto-
plasmic nature. The chlorophyll is not actually

1 Prof. B. Moore on The Origin a.id Mature of Life, pp. 178,
183. Also Lectures on tht Physiology of Plants, by S. H. Vines,
PP- 153. 157-

Metabolism 17

combined with the protoplasm, but is retained
mechanically within it. The function of chloro-
phyll is to absorb certain rays of light, and
enable the protoplasm with which it is inti-
mately connected to avail itself of radiant
energy of the sun's rays, for the construction of
organic substance from carbon dioxide and
water.

Every kind of healthy living matter pos-
sesses the power of helping to convert the
nutrient matter which, as a rule, is carried to it
by the circulating fluid into such a form as
can be incorporated with its protoplasmic ele-
ments, thus replacing its worn-out particles;
this process is technically known as Meta-
bolism. Professor Huxley, when referring to
this power, describes the incoming atoms as
being piled up in the cell under the action of
chemical force, while before they leave it they
tumble down into smaller heaps. The energy
set free in the tumbling down of these atom
groups affords a constant store of working
energy to the cell-contents.

The human brain, for our purposes, may be
described as consisting of an innumerable multi-

B

1 8 Instinct and Intelligence

tude of fully-charged nerve cells, exposed to a
constant flow of incoming energy derived from
internal and external sources. This flow effects
a discharge of part of the latent energy of the
cells in the form of nervous energy, and may
become manifest in instinctive and intellectual
processes.

With regard to Instincts, more than a century
ago Sydney Smith wrote as follows : " The most
common notion now prevalent with respect to
animals is that they are guided by instinct ;
that the discriminating circumstance between
the minds of animals and of man is that the
former do what they do from instinct, the latter
from reason. When I call that principle upon
which the bees or any other animal proceed to
their labour the principle of instinct, I only
mean that it is not a principle of reason. How-
ever the knowledge is gained, it is not gained as
our knowledge is gained. It is not gained by
experience or imitation. ... It cannot be inven-
tion, or the adaptation of means to ends, because
as the animal works before he knows what event
is going to happen, he cannot know what the
end is to which he is accommodating the means :

Instinctive Behaviour 19

and if he be actuated by any other than these,
the generation of ideas in animals is very
different from the generation of ideas in men.
Ants and beavers lay up magazines. Where do
they get this knowledge that it will not be as
easy to collect food in rainy weather as it is in
summer? Men and women know these things,
because their grandpapas and grandmammas
have told them so; ants, hatched from the egg
artificially, or birds hatched in this manner, have
all this knowledge by intuition, without the
smallest communication with any of their rela-
tions." l

Professor Lloyd Morgan defines " instinctive
behaviour as that which is, on its first occur-
rence, independent of prior experience; which
tends to the well-being of the individual and
the preservation of the race ; which is similarly
performed by all the members of the same more
or less restricted groups of animals ; and which
may be subject to subsequent modification
under the guidance of experience." 2 He holds

1 Sketches of Moral Philosophy, by Sydney Smith, pp. 240,
244, 247.

2 Instinct and Experience, by C. Lloyd Morgan, D.Sc., Professor
in the University of Bristol, pp. 5, 28, 79, 204.

B 2

2O Instinct and Intelligence

that such behaviour is a more or less complex
organic or biological response to a more or less
complex group of stimuli of external and in-
ternal origin; and depends upon the inherited
structure of the nervous system of a definite
part of the brain.

It would be difficult to devise a clearer defini-
tion of the term Instinct than that given by
Professor Lloyd Morgan; the nervous matter
through whose agency action of this kind is
brought into play is inherited. The energy
attached to its molecules being set free by vari-
ous stimuli received from external objects, and
internal movements becomes manifest in de-
finite action. That matter having instinctive
properties has been derived from a common
ancestral source, and has developed under the
laws of natural selection, is apparent from the
fact that the same kind of movements are made
in similar environmental conditions, without
being taught, by newly-born beings belonging
to the same species, located in widely separated
parts of the world.

The exciting agent or mode of energy is
called a stimulus, which is always due to a

Internal Stimuli 2 1

change of environment. Internal stimuli result
in part from energy derived from the sensory
organs of ligaments, muscles, and other struc-
tures in contraction, pass by afferent fibres to
motor areas of the cerebral cortex, and by re-
leasing a portion of their potential energy
bring " motorial " or " kinaesthetic " sensations
into play. Beyond this various biochemical
stimuli known as " hormones " are formed in
various glands of our bodies; they enter the
blood stream and activate among other struc-
tures the instinctive sensori-motor elements of
the central nervous system. It seems possible
that some of these hormones, by exciting the
basal nervous matter of a new-born infant's
instinctive elements, may lead to the move-
ments which guide his limbs to seize and
direct the nipple of his mother's breast to his
mouth.1

Instinct is in fact a fundamental property of
certain inherited forms of living matter, as is
demonstrated by the behaviour of some of the

1 An Essay on Character in Relation to the Emotions and
Instincts, Science Progress, No. 36, April, 1915, pp. 683-685, an
Introduction to the Study of the Endocrine Glands and Internal
Secretions. By Sir Edward Schafer.

22 Instinct and Intelligence

simplest kinds of organism, such, for instance,
as the Amoeba proteus.1

Amoeba are of microscopic size, and may be
found moving about on the mud at the bottom
of many ponds and ditches ; each one of these
unicellular beings contains a single minute
speck of nucleated protoplasm. The proto-
plasm forming the substance of these unicellular
beings consists of a network of proteid ele-
ments, the interspaces being occupied by semi-
fluid contents. The Amoebae do not possess a
nervous system, eyes, locomotor, or any other
permanent organs; their nucleus, however, is
composed of a somewhat different variety of
protoplasm from that which forms the body of
the cell. The worn-out elements of these living
cells are replaced by metabolic processes (p. 17),
and it is thus supplied with a constant reserve

1 For half a century the author of this volume has been more
or less occupied in studying, under the highest magnifying powers,
the life-history of some of the simplest organisms ; his attention
having been directed, when serving in India, to this subject in
an effort to define the specific germs which he was convinced gave
rise to Asiatic cholera. (A Treatise on Asiatic Cholera, by N. C.
Macnamara, Calcutta, 1869.; It would be out of place here to
recapitulate the results of his work, especially as reliable descrip-
tions of the behaviour of lower organisms, including that of the
Amoeba, are now at command, written by impartial and acknow-
ledged authorities in this department of science. (Prof. H. S.
Jennings, The Behaviour of Lower Organisms, New York, 1906.)

Instinct Inherent in Protoplasm 23

of chemical energy. When an Amoeba has
grown to a definite size its nucleus and body-
substance separate into two parts which move
away from one another, and two young Amoebae
are formed exactly resembling their parent.

Amoebae from time to time, in response to
certain stimuli, extend outwards retractile pro-
cesses from their body substance known techni-
cally as pseudopodia. By aid of these feelers
an Amoeba is able to move about over the mud
forming the bottom of the pond it inhabits.
When an Amoeba comes in contact with solid
particles, Dr. Dendy1 writes, we notice that it
has the power of distinguishing one particle
from another, and that one which is good for
food adheres to a pseudopodium and is carried
into the body of the animal, where it is digested.

Professor G. C. Bourne, when describing
Protozoa, or single-cell organisms, remarks that
they must exercise some sort of selection in in-
gesting solid matter; for if they did not they
would take in every particle of convenient size
that they meet, and they do not. He further

1 Outlines of Evolutionary Biology, by A. Dendy, D.Sc., F.R.S.,
p. 16.

24- Instinct and Intelligence

states that an Amoeba living in water containing
numerous diatoms of relatively large size, may
be seen to engulf a number of these apparently
inconveniently large objects almost to the ex-
clusion of other substances, thus making a dis-
crimination between things good for food and
things not good. Moreover, if watched for a
long time, the movements of an Amoeba are
seen to be of a purposive character; that is to
say, they are adapted to the necessities of the
organism, as is evident when an obstacle is met
with, or when the animalcule endeavours to seize
and ingest some object that rolls away from it,
or attempts to capture a smaller member of its
own kind for food.1

Professor Jennings on one occasion saw a
large Amoeba seize a small one and encircle it
by means of pseudopodia which were then re-
tracted; but the embrace of the small by the
large Amoeba not being complete, the former
animal escaped; upon which the large Amoeba
reversed the course it was following and pur-
sued its prey. Professor Jennings states with

1 An Introduction to the Study of the Comparative Anatomy of
Animals, by Gilbert C. Bourne, M.A., D.Sc., Professor of Com-
parative Anatomy, University of Oxford, Vol. I., p. 134. Second
edition.

Instinctive Movements of Amoeba 25

reference to this performance that it is difficult
to conceive each phase of action of the pursuer
to be completely determined by a simple pre-
sent stimulus. For example . . . after Amoeba
b had escaped completely and was quite
separate from Amoeba c, the latter reversed its
course and recaptured b. What determines the
behaviour of c at this point ? If we can imagine
all external physical and chemical conditions to
remain the same with the two Amoebae in the
same relative position, but suppose at the same
time that Amoeba c has never had the experi-
ence of possessing b, would its action be the
same? Would it reverse its movements, take
in b, then return on its former course ? " One
who sees the behaviour as it occurs hardly resists
the conviction that the action at this point is
partly determined by the change in c, due to
the former possession of b, so that the beha-
viour is not purely reflex, but partly the result
of memory." l

1 Behaviour of Lower Organisms, by H. S. Jennings, p. 24.
New York, 1906.

Prof. W. B. Hardy, when discussing the nature of the move-
ments made by Amoebae, observes : "They manifest discrimination,
imperfect no doubt, but as the choice is beneficial it contains an
element of purpose." — Science Progress, October, 1906, p. 182.

26 Instinct and Intelligence

From the above evidence, which we can con-
firm by our own experience, we hold that the
behaviour displayed in response to appropriate
stimuli by the simplest forms of animals is
instinctive, employing that term as denned by
Professor Lloyd Morgan (p. 19). The behaviour,
however, of the Amoeba above referred to was
to some extent the result of memory. Huxley,
in his well-known address to the British Asso-
ciation in the year 1874, referring to this sub-
ject, remarks that impressions made on certain
kinds of living matter leave behind molecules
competent on being stimulated to their repro-
duction— " sensigenous molecules," so to speak,
which, he adds, " constitute the physical
foundation of memory." We thus arrive at the
conclusion that not only instinctive behaviour,
but also memory, is a fundamental property of
living animal protoplasm. This idea is sub-
stantiated by the following evidence :

Sir Francis Darwin, in his address as Presi-
dent of the British Association in the year 1908,
not only concurs in Huxley's views on this sub-
ject, but quotes Regnano, Hering, and Semon
as postulating the existence in living proto-

Instinct and Memory 27

plasm of elements possessing the basis of
memory and inheritance. For example, Stentor,
although its body-substance and nucleus are
structurally of greater complexity than those of
Amoeba, is nevertheless a unicellular being.
The movements effected by the protoplasm of
this animal have been carefully studied by Asa
A. Schaeffer; he gives in detail a clear account
of his experimental work, and arrives at the
following conclusions : — l

1. Stentor caeruleus excises a selection
among particles that are brought to its food-
pouch; certain particles are rejected, others are
carried to the mouth and ingested ; in selecting
food it probably reacts to physical properties
only or chiefly, and not to chemical properties.

2. Stentor discriminates very accurately be-
tween organisms and indigestible particles, the
latter of many sorts which have for thousands
of generations not come in contact with Stentor
are nevertheless rejected.

1 fhe Journal of Experimental Zoology, Vol. VIII., No. i,
January, 1910, pp. 894-5.

Prof. A. J. Ewart *"emarks, when referring to the movements of
organisms possessing locomotory organs, that they have "acquired
the power of directing and controlling the natural forces to their
own benefit." — Physics and Physiology of Protoplasmic Straining
in Plants, p i '2.

28 Instinct and Intelligence

Difflugia, one of the simplest of unicellular
beings, when it has reached its full size, pro-
trudes long pseudopodia which move over the
mud at the bottom of the water it inhabits. If
its pseudopodia come in contact with grains of
sand they contract with the sand adhering to
them, and pass it into their body. These grains
of sand are subsequently employed as materials
to form a new shell for the Difflugia's offspring.
Professor Verworn, instead of grains of sand,
placed small fragments of coloured glass near
a Difflugia; some time afterwards he noticed a
heap of these fragments on the bottom of the
shell. He then saw a protrusion of protoplasm
issue from the shell in the shape of a new
Difflugia. Thereupon, the material collected by
the parent organism — the fragments of coloured
glass — were used to envelop the substance of
the young animal, and came to form a shell
similar to that enveloping the parent. Beha-
viour of this kind seems guided by instinct and
memory.

Before leaving the Protozoa we may refer to
the Volvocinse, which appear to occupy an inter-
mediate position between unicellular and multi-

Volvox

29

cellular beings. In this genus the cells in place
of simply dividing, as in the Amoebae, into inde-
pendent organisms unite and form a colony
consisting, it may be, of as many as 1,200 cells;
each cell consists of a mass of nucleated proto-
plasm which is
united to its neigh-
bour by means of
processes formed
from their body-
substance ; from
each cell two fla-
gella project by
means of which the
colony is paddled
through the water.

(Fig. i.)

The cells of a
Volvox multiply by
a process of division, but after a time they ap-
pear to become exhausted ; or at any rate, some
of the cells fuse to form one or more large or
female organ cells ; at the same time other cells
of the colony develop smaller flagellated male
cells, which escape from the parent colony and

FIG. i. — Volvox, showing the small
ciliated somatic cells and eight large
germ cells. (Drawn from life by
J. H. Emerton. See E. B. Wilson,
The Cell in Development and In-
heritance, p. 123.)

30 Instinct and Intelligence

swim about in the water until they meet with one
of the female cells, into which they pass ; fertili-
sation takes place by changes similar to those
which characterise the reproduction of the germ
cells of the higher orders of plants and animals.
From our point of view the interesting feature
in reference to the life-history of some of the
Volvocinse is the evidence it affords that, with
structural modifications in their protoplasm,
there is a corresponding alteration in the nature
of the work it performs.

CHAPTER II

Multicellular animals — Sex — Hydromedusae — Hydi
Appearance of nerve cells — Medusoids — Their
nervous system- — " Eye-spots " — Purposive move-
ments of Hydra according to stimulus — Purposive
movements of Medusoids dependent on existence
of nervous system — Purposive movements of uni-
cellular organisms accounted for — Development of
sensory organs — Light as stimulus.

OUR attention thus far has been fixed on uni-
cellular beings with the exception of Volvox,
which consists of an aggregation of cells fore-
shadowing the structural arrangement of all
multicellular animals, since, besides the aggre-
gation of individual cells to make up its body,
the germinal elements of some of these cells
separate from the rest of its substance so as
to produce male and female cells. The indi-
vidual is no longer reproduced by the simple
division of a parent cell into two young beings,
but depends mainly on the conjugation of male
and female cells.

32 Instinct and Intelligence

It is well in passing from the consideration
of unicellular to multicellular beings to bear
the above principles in mind, for they apply to
the reproduction of all multicellular animals.
Germinal cells alone possess the power of
giving rise to a being resembling more or less
closely in the structural, and potential powers
of the stock from which these cells have been
derived, powers which they pass on to succeed-
ing generations. The mass of cells which
form the various tissues and organs of an
animal's body, including the nervous system,
are known as somatic cells; worn-out or injured
somatic cells are replaced by fresh cells pro-
duced by asexual division of neighbouring like
cells, but are incapable of giving rise to new
beings. At the same time, we must never forget
that the living protoplasm of every form of
animal cell possesses a certain proportion of
elements having mnemic and instinctive
functions.1

1 It has been assumed that a fertilised cell, such, for instance,
as that of a human being, which has a diameter of about
^V mm., is too minute in size to contaii a sufficient amount of
matter to produce a man with all his structural and mental
qualities. This idea, however, is not entertained by those best
qualified to form an opinion on the subject. Prof. J. G.
M'Kendrick states that taking the average cubical diameter of a

Multicellular Organisms 33

The simplest type of multicellular animal
(Metazoa) is to be found among the Sponges.1
Only a slight degree of co-ordinate action exists
between the cells forming the bodies of these
animals, and they thus represent a primitive
grade of organisms beyond which other Metazoa
have passed. (See Appendix at end of Chap.
VII.)

Following the Sponges, in the ascending
scale of the animal kingdom, we come to the

human ovum at 2V mm. and an atom at nn^oVou of a millimetre,
and assuming that about fifty exist in each organic molecule
(proteid, etc.), the cube would contain at least 25,000,000,000,000
organic molecules. Again, the head of the spermatozoid, which
is all that is needed for the fecundation of an ovum, has a diameter
of about ^J<r mm. Imagine it to be a cube ; it would then contain
25,000,000,000 organic molecules. When the two are fused
together, as in fecundation, the ovum starts on its life with over
25,000,000,000,000 organic molecules. If we assume that one half
consists of water, then we may say that the fecundated ovum may
contain as many as about 12,000,000,000,000 organic molecules.
Clerk Maxwell's argument that there were too few organic mole-
cules in an ovum to account for the transmission of hereditary
peculiarities does not apparently hold good. Instead of the number
of organic molecules in the germinal vesicle of an ovum numbering
something like a million, the fecundated ovum probably contains
millions of millions. Thus the imagination can conceive of com-
plicated arrangements of these molecules suitable for the develop-
ment of all the parts of a highly complicated organism, and a
sufficient number to satisfy all the demands of a theory of heredity.
Such a thing as a structureless germ cannot exist. Each germ
must contain peculiarities of structure sufficient to account for
the evolution of the new being, and the germ must therefore be
considered as a material system. — See Nature, September 26, 1901,
p. 547.

1 Treatise on Zoology, edited by Sir Ray Lankester, Part II.,
p. 2, by Prof. E. A. Minchin, F.R.S., on Sponges.

C

34 Instinct and Intelligence

Hydromedusae. This class of animals is of
particular interest, as it includes the lowest
order of beings possessing nerve cells, together
with definite sensory organs, or structures
specially adapted to receive, and transmit to
nerve cells various modes of energy acting on
the surface of the animal's body, the result of
which frequently becomes manifest in instinc-
tive movements.

The Hydromedusae present two main forms,
the non-sexual polyps or Hydra, and the sexual
Medusae, such as jelly-fish and sea anemones;
as an example of the former we may refer to
the small yellow or light brown fresh-water
polyps known as Hydra fusca. The body of
this creature consists of a cylindrical sac, its
walls being formed by an outer and inner layer
of cells, with an intervening gelatinous con-
tractile substance. This Hydra is commonly
found attached by one end of its body or foot
to some solid substance, such as a water plant ;
the other end of the body opens to the exterior
by an orifice which leads to the central cavity
or digestive department of the animal. Round
the Hydra's mouth from six to nine tapering

Sensory Organs

35

processes of the animal's body, known as its
tentacles, act as feelers and prehensile struc-
tures. The external surface of the body and
tentacles of Hydra are covered by minute
bristle-like projections, some of which are

FIG. 2.— Sensory organs or cells connected with a nerve cell. C,
Protoplasmic fibre of a tactile sense-cell forming nodular enlarge-
ments. D. Cnidoblast connected with nerve cell by a protoplasmic
fibre.

named palpocils; they are formed of an out-
growth of the protoplasm of the cylindrical cells
which constitute the ectoderm or outer skin
layer of the animal. (Fig. 2.)

c 2

36 Instinct and Intelligence

Palpocils, projecting as they do from the
outer free surface of cylindrical cells, are well
adapted to receive, and transmit any tactile
impressions made on them to the protoplasmic
contents of the cell of which they form a part.
In this way the palpocils with their cells con-
stitute a rudimentary sensory organ or receiver
of energy from the outer world ; they act some-
what after the fashion of a trigger, and when
stimulated discharge a part of the potential
energy stored in the living substance of the
cylindrical cells. These cells are constantly
kept primed with energy derived from the
metabolic processes carried on by their proto-
plasmic elements. Energy thus released from
the cells becomes manifest in definite move-
ments of the Hydra's body or tentacles; be-
cause the deep or attached part of these cells is
prolonged into a system of nerves and con-
tractile structures.

Beneath the ectoderm of Hydra nerve cells
have been detected. These cells are in direct
communication with — in fact, are a part of—
the living substance of cylindrical cells, arid
possess therefore, in common with other kinds

Origin of Nerve Cells 37

of protoplasm, inherent mnemic and instinctive
elements. Part of the energy set free by stimuli
acting on the palpocils and the living substance
of their cylindrical cells passes to corresponding
nerve cells, and by means of their instinctive
elements is transformed into purposive nerve
force, which extends to groups of muscle cells,
causing them to contract in a co-ordinate
manner, and thus to give rise to instinctive
movements of certain parts of the animal's body.
It is, therefore, through the instrumentality
of a system consisting of a sensory organ,
nerve cell, and muscular fibres, that the
automatic or instinctive movements of the
animals to which we have referred take
place.

Between the bases of the cylindrical cells of
Hydra are a number of ovoid cells, some of
which become developed into germ cells, others
are so much elongated at one end as to form a
fibre armed at its base with a sharp spine.
(Fig. 2.) By a process of introversion of the
wall of the cell this fibre comes to assume a
spiral form within the cell, with one of its ends
projecting outwards on the surface of the

38 Instinct and Intelligence

animal's body. This apparatus is described as
a cnidocil, and, with the palpocils, forms a
delicate bristle-like covering to the body and
tentacles of Hydra. If a small living animal
happens to come in -contact with these pro-
cesses as chemically to irritate the free ends of
its cnidocils, their barbed fibres are released,
and darting out of their cells sting the intruder
to death ; the prey is then seized by the Hydra's
tentacles, carried to its mouth, and passed into
its body cavity, there to be digested and
assimilated.1

Hydra fusca, like many of the Hydro-
medusae, is reproduced by a process of budding ;
but other genera of this family, such as the
small Obella geniculata often found attached to
the oar-weed, give rise by sexual processes to
Medusae commonly known as " jelly-fish." The
various phases in the reproduction of the
Hydroids and Medusoids, although a subject
of great interest is outside the province of this
work ; we, therefore, pass on at once to con-
sider the structure of a typical form of Medusa,

1 Quarterly Journal of the Microscopic Society, February, 1905,
p. 615. Mr. G. Wagner on "Some Movements and Reactions of
Hydra.''

Jelly-fish

39

in relation to the automatic or instinctive
behaviour of these animals.

The Medusoids are generally bell-shaped.
As a typical example of these animals, we may
refer to a jelly-fish known as Sarsia (Fig. 3),
which may be said to
consist of a tubular
body and manubrium
with a mouth or open- c\\
ing, from which a pas-
sage leads to its diges-
tive cavity. From this
cavity canals pass out-
wards to terminate in a
passage which extends
round the margin of
the bell. In Sarsia
and many other Medu-
soids a shelf or velum
projects inwards from
the margin of the bell, and at the junction
of the velum and rim of the bell tentacles hang
downwards. (Fig. 3.)

The ectoderm or outer surface of this Medusa
is formed by a layer of flattened cells. Mus-

FIG. 3. — Diagram of a Medu-
soid (Sarsia). m, manubrium ;
es, external surface of bell ;
sbr subumbral surface ; v v,
velum ; su, subumbral .cavity ;
cl, circular canal ; t t t, ten-
tacles. (After Lankester's
Treatise on Zoology, Part II.,
p. 17, The Hydromedusae.)

40 Instinct and Intelligence

cular fibres surround the manubrium and extend
outwards over the inner surface of the bell ; they
may be followed into the velum, which is essen-
tially a muscular structure.

We find, in connection with the ectoderm of
the under surface of the bell and its muscular
fibres, a complex arrangement of nerve cells and
fibres. (Fig. 4.) Mr. G. J. Romanes compares
the network of nerve fibres
of the inner subectodermic
layer of a Medusoid's bell
with a " disc of muslin, the
fibres and meshes of which
are finer than the closest
cobweb." l

The nerve cells originate,
as in Hydra, p. 36, from
the sensitive protoplasmic
substance of the outer layer (ectoderm) of cells
forming the margin, and under-surface of the
bell. In some Medusoids a double circle of
nerve cells and fibres extends round the struc-
tures constituting the margin of the bell ; from
these nerve cells numerous fibres are given off

1 G. J. Romanes on jelly-fish, Star-fish, and Sea-Urchins,
pp. 17, 20.

FIG. 4.

Sensory Organs 41

which terminate in the muscular structures of
the manubrium and other parts of the animal.

In connection with the nervous system of
Medusoidswe find tactile sensory organs, similar
to those which exist in Hydra, spread over their
tentacles and over certain regions of their
bodies. In
addition to
these sensory
organs some of
the Medusae
present definite
structures de-
rived from the
ectoderm or
living s u b-
stance of the
outer layer of
cells, which are
described as statocysts and ocelli ; these organs
are for the most part located on the margin of
the bell, at or near the base of the tentacles.

The statocysts consist of minute masses of
organic and calcareous matter, supported in a
cavity containing sensory fibres, which com-

FIG. 5. — Statocyst. d1, superficial layer
of ectoderm ; d2, deeper layer ; h, specia-
lised cells of ectoderm ; hh, supporting
filaments ; np, nervous structures ; npr,
upper nerve ring ; r, endoderm ring of
circular canal. The calcareous body
and cavity of eense-organ seen above.
(Hertwig.)

42 Instinct and Intelligence

municate vibratory impressions to subjacent
nervous structures. (Fig. 5.) Their function
appears to be that of adjusting the balance of
the animal's swimming-bell in its passage
through the water.

The ocelli consist of an arrangement of
sensory and pigment cells grouped into a
definite organ, in which some of the ocelli
project above the surface of the ectoderm in

the form of a
cuticular lens.
(Fig. 6.)

Ocelli are
sometimes al-
luded to as

FIG. 6. " eye-spots," in

consequence of

the part they play as receivers of the waves
of light which reach the animal from the
outer world. Mr. Romanes has proved that
Medusoids are influenced in their movements
by the stimulus of light; if the animal is
vigorous and swimming freely in water, the
effect of a momentary flash of light thrown
upon it during one of its natural pauses

Behaviour of Hydroids 43

immediately starts a bout of swimming.1 He
states that when the margin of the bell, together
with all its ocelli are removed, the swimming
bell, although still able to contract, no longer
responds to luminous stimulation of any kind or
degree. But if some of the ocelli are left in
situ, light induces an unfailing response of the
entire animal.

We may now pass on to consider the move-
ments of Hydra in order to determine how far
they are directed by instinctive processes.
Although a Hydra is usually attached by its
foot to some solid substance, its body and
tentacles undergo constant contractions and
expansions; these movements are augmented
by any vibrations, such as those caused by
slamming the door of the room in which the
aquarium containing the Hydra is placed.2
Reaction to stimuli of this kind leads to move-
ments which enable the Hydra's tentacles to
explore the surrounding water, and thus increase
its chance of capturing any suitable object which

1 Jelly -Fish, Star-Fish, and Sea-Urchins, by G. J. Romanes,
M.A., LL.D., F.R.S., p. 39.

2 The Quarterly Journal of Microscopic Science, New Series,
No. 192, p. 585, G. Wagner on "Some of the Movements and
Reaction of Hydra."

44 Instinct and Intelligence

may be floating about within its reach. Hydra
can move from one spot to another without
difficulty. These movements are effected as
follows : the animal's body and tentacles ex-
pand and bend over to one side ; as soon as the
tentacles touch the solid substance to which its
foot is attached they become fixed to it; they
then contract, the animal's foot relaxes its
grasp, and its body moves so that the Hydra
comes to stand on its tentacles; the body then
bends over until its foot reaches something to
which it can fix itself, the tentacles loosen their
hold, and the animal resumes its former upright
position. In other cases the foot of the Hydra
glides along the surface it is attached to until
it comes close to the tentacles, which then leave
their hold, with the result that the Hydra moves
forward. When mechanically stimulated, the
body of a Hydra contracts at the same time as
its tentacles, as if to offer a smaller surface
to the cause of irritation; if, however, the
mechanical stimulus is continued, the animal
relaxes its foothold and moves away slowly in
the manner above described.

If a Hydra is kept without food for a week or

Hydra 45

ten days, and then a particle of raw meat is
placed near one of its tentacles, it at once
fastens itself on the meat, and then the other
tentacles close round the food and contract;
in this way the particle is conveyed to the
Hydra's mouth, which opens to receive it, and
closes again as the food passes into the body
cavity where it is digested. If a particle of
meat is dropped by a Hydra when being con-
veyed to its mouth, the animal does not appear
to make any effort to recover it, although its
tentacles may continue to move about in an
excited manner for some little time. If a piece
of filter-paper is placed near a starving Hydra,
the animal does not attempt to seize it. "A
mechanical stimulus alone, then, cannot call
forth a food reaction." 1 In addition to the
mechanical stimulus to produce such a reaction,
the object must possess chemical properties of
a definite kind. For instance, a Hydra will
seize and swallow a morsel of filter-paper which
has been soaked in beef-tea.

From the above facts we learn that Hydra

1 The Quarterly Journal of Miscroscoftic Science, Now Series,
No. 192.

46 Instinct and Intelligence

when undisturbed can move from one to another
position; when any part of the surface of its
body or tentacles is mechanically or chemically
stimulated, it responds by contracting more or
less completely according to the intensity of the
stimulus. A localised stimulus applied at brief
intervals is at first followed by corresponding
contractions, but after a time the stimulus loses
its effect and contractions cease to occur;
though if the cause of irritation is continued
the Hydra loosens its foothold, and, if possible,
moves away from the cause which is irritating
it. Hydra only reacts to the stimulus of food
when hungry, and then the complex, and to
some extent co-ordinate movements of its
tentacles and mouth necessary to enable it to
seize, and swallow its food require a combina-
tion of mechanical and chemical stimuli to pro-
duce an efficient response of the structures
concerned in the action.1

The fact to which we desire to draw special
attention is that the most conspicuous move-
ments made by the animals referred to are pur-

1 Am. Jour. Physiol., Vol. VIIL p. 29, "The Animal Mind,"
by M. F. Washburn, p. 214.

Behaviour of Medusoids 47

posive in character, and could not have been
acquired by imitation or from having been
taught. That these motor effects are, however,
due to a common cause is shown by the fact
that in whatever part of the world Hydroids
exist they respond in like manner to stimuli,
and the response is repeated by succeeding
generations of these animals.

We may now pass on to consider the be-
haviour of Medusoids. The origin of the
nerve cells of this order of animal is similar
to that of Hydra; both of them being derived
from, and remaining in close connection with
the living substance of the ectoderm, out of
which also the various sensory organs are
developed.1

With sensory organs and a nervo-muscular
system such as those we have described as
entering into the structures forming the body,
and tentacles of Medusoids, we can understand
how it comes to pass that, if we stimulate a
point situated on the under surface of the
margin of a jelly-fish's swimming-bell, its

1 A Treatise on Zoology, Edited by E. Ray Lankester, Part II.,
"The Anthozoa," by Prof. G. C. Bourne, p. 10.

48 Instinct and Intelligence

manubrium first contracts, and with unerring
aim brings its mouth to the point stimulated.
If another spot is irritated, the manubrium
leaves the first and moves to the second spot;
and when left to itself visits first one and then
another irritated point, dwelling on those most
severely irritated. (Fig. 7.)

If the tentacles or the margin of the swim-
ming-bell of a Medusa (Gonlonemus murbachii)
be stimulated by a weak electric current, a series
of rhythmical contractions and
expansions of the structures
forming its body and velum
takes place, which enable the
animal to swim away from the
source of irritation. If a small
bit of meat is placed in the water near one of
these Medusae, so as to touch more than one of
the animal's tentacles, they move simultaneously
to the food; at the same time the manubrium
stretches out to meet the contracting tentacles,
and the food is thus taken into the animal's
mouth and passed on to its digestive cavity.

The movements made by the manubrium and
swimming-bell of the jelly-fish above referred

Nervous System of Jelly-fish 49

to clearly show that, when definite parts of its
sensitive surface are appropriately stimulated,
its body-substance responds by well-ordered
and distinctly purposive movements, that is to
say, by instinctive behaviour calculated to pro-
mote the well-being of the animal and the
species to which it belongs. When the entire
margin of the bell of a living jelly-fish, in-
cluding therefore the whole of its sensory
organs and system of nerve cells is excised,
neither mechanical nor any other form of
energy applied to the remaining part of the
bell produces any movement in it or in the
manubrium. In place of excising the margin
of the bell, Romanes made an incision above
the situation of its nerve cells, parallel to its
margin. Under these conditions the move-
ments of the manubrium became uncertain; it
no longer bent down to the seat of irritation,
but dodged about from one to another part of
the margin of the bell; it had seemingly lost
its power of localising the spot irritated.1 The
manubrium, under these conditions, being acted

1 Jelly-fish, Star-fish, and Sea-urchins, by G. F. Romanes,
P- 33-

D

50 Instinct and Intelligence

on by a diffused nervous force, is impelled to
wander first here and then to another spot, in
place of taking a decisive instinctive action.

From these experiments we learn that the
definite co-ordinate action of the different parts
of a Medusoid's body takes place through
means of its nervous system.

The ordinary swimming movements of a
Medusoid depend on the regularly recurring
contraction and relaxation of the muscular
fibres of the bell and velum. This action in
its turn depends on a constant flow of energy
from its surroundings to the sense-organs, and
from thence to the nervous and muscular
systems, which are charged with potential force
derived from metabolic processes carried on by
their living protoplasm. A discharge of energy
from a series of nerve cells having thus been
released, their living matter for the instant is
exhausted, and until it receives a fresh supply
of energy derived from metabolic processes
it cannot act on the muscular fibres. During
the instant, therefore, that the supply of
potential energy is being renewed, the kinetic
energy received from the sense-organs is sus-

Nervous System of Medusoids 5 1

pended, and the tension of the muscles of the
bell and velum is relaxed; but when the
potential energy of the cell is restored, external
stimuli produce another discharge of nervous
energy, followed as before by contraction of
muscular fibres. So long, therefore, as the
fundamental properties referred to are carried
on by the living matter of the system, and a
supply of potential energy is secured, regularly
recurrent contractions and relaxation of the
muscular fibres of the bell and velum take
place, whereby the swimming movements of the
animal are effected.1 We thus come to appre-
ciate the force of Professor Lloyd Morgan's
oft-repeated remark that the instinctive be-
haviour of animals " depends upon the inherited
structure of their nervous system."

It is, however, evident that unicellular beings
such as Amoeba, Stentor, and Euglena, al-
though they do not possess a nervous system,
nevertheless respond by appropriate purposive
movements to various forms of energy applied
to their body-substance or living protoplasm,

1 Halliburton 's Handbook of Physiology, p. 19 1, Seventh
Edition.

D 2

52 Instinct and Intelligence

which must therefore contain elements capable
of transforming ordinary modes of energy act-
ing on them into purposive movements. We
hold that in the course of the evolution of the
ascending classes of animals purposive elements
such as those governing the behaviour of uni-
cellular beings have separated, or become dif-
ferentiated from the rest of the protoplasmic
elements, so as to constitute a very important
part of the living matter of the nerve cells of
more highly organised beings ; elements of this
description in the course of time have become
the instruments whereby energy derived from
external and internal sources is transmuted into
force, which becomes manifest in purposive or
instinctive movements of animals.

The delicate structures forming the various
sensory organs of Medusoids are of a distinctly
higher order than those of lower orders of
beings; and we find a progressive evolution of
these tissues in advancing families of animals.
Doubtless the evolution of these structures, like
those of other parts of the body, is largely attri-
butable to natural selection; but these changes
of structure in a continuous series throughout

Eye-spots 53

vast periods of time, appear to demand the inter-
vention of some more specific mode of energy
than that implied in the hypothesis of the sur-
vival of the fittest. We seem to require the aid
of some definite and persistent underlying force
which has gradually moulded the living matter
of these structures into forms adapted to re-
ceive, and modify the different kinds of energy
acting on them, so that it becomes capable of
stimulating corresponding centres of nervous
matter into purposive action. We can best
illustrate our meaning by referring to the
development of visual sensory organs.

The simplest known form of an organic
visual apparatus is that of an " eye-spot," such
as exists in Euglena, a unicellular being con-
stituting a link between animals and plants.
Near the anterior end of the cell forming one
of these beings a bright red spot exists, which
consists of a meshwork of sensitive protoplasm
containing a number of red particles. Exter-
nally this spot is covered by one or more
granules adapted to receive, and concentrate
waves of light on the subjacent pigmented
sensitive mass. There can be no question as

54 Instinct and Intelligence

to the fact that the movements made by
Euglena are influenced by the stimulus of light;
it is, however, uncertain how far the structures
forming the eye-spot determine these move-
ments ; but in the case of Volvox each cell pos-
sesses a well-defined refracting lens behind
which is a layer of coloured sensitive matter.
The movements of this organism are clearly
influenced by the stimulus of light, and its eye-
spots are essential to these movements.

It is by no means difficult to follow the transi-
tional stages of the structures constituting the
eye-spots of Euglena and Volvox into the
forms these tissues have assumed in the ocelli of
the Medusoids and the eyes of Mammalia. The
pigmentary elements in each of these orders of
beings give precisely similar reactions to light,
and their dioptric arrangement is built up on
the same general plan ; so that we are disposed
to hold they originally proceeded from a
common ancestral stock.1 The regular evolu-
tion of structures of this description could not
have been effected, much less maintained, by

1 Comparative Anatomy of Animals, by Gilbert C. Bourne,
Vol. I., p. ig<t.

Adaptability of Living Matter 55

the play of an ever-varying environment. It
could only have been brought about by some
definite and persistent force underlying or
working with that implied under the term of
natural selection. (See Appendix.) As regards
the development of the structures forming the
organ of vision, it appears to us we have in that
mode of energy we call light a force capable
of moulding, on general lines, living substance
so as to adapt it to the needs of the various
ascending orders of beings. It is evident that
waves of sunlight must have acted constantly on
organic matter from the time this substance first
came into being. It is, therefore, conceivable
that light might, in the course of time, have
moulded the molecules of primitive forms of
organic matter into structures which gradually
became adapted to its own incidence, as well as
to that of the environment. The similarity of
the structure constituting the visual organs of
different classes of animals can thus be ac-
counted for, their living substance having re-
sponded in like manner to a direct and never-
failing similar form of energy. The more and
more complex structures forming the eyes of

56 Instinct and Intelligence

ascending orders of animals would thus be
something akin to a deeper and deeper impres-
sion of light on a substance which, being
organised, possesses a special aptitude for
receiving and rendering it hereditary.1 Pro-
fessor F. Soddy, when referring to this subject,
observes that the human eye has become
adapted through long ages to the peculiarities
of the sun's light, so as to make the most of
that wave-length of which there is the most.2
In the following chapter we hope to show that
in the Star-fish the connection between its visual
sensory organs, their corresponding nervous
system, and the instinctive behaviour of these
animals is even more conclusive than that which
exists in the case of their allies the Medusoids.

1 Creative Evolution, by H. Bergson, p. 73.

2 Matter and Energy, by F. Soddy, p. 193.

CHAPTER III

The nervous system of the Star-fish — Purposive move-
ments dependent on presence of sensory organs —
Development of head in animals — Earth-worms —
Rudimentary brain — Hereditary instinctive move-
ments— Crayfish — Increased complexity of brain
corresponding- to higher order of instinctive move-
ments— Labyrinth experiments — The brain of
insects — Their sensory organs — Highly developed
instinctive processes in Ants, etc. — Automatic
processes.

IN the preceding chapters we have endeavoured
to show that some of the elements of living
protoplasm possess a special aptitude for
becoming adapted to the incidence of recurring
modes of energy; in this way the sensory and
nervous structures of the ascending classes of
animals have become moulded on a uniform
plan. The changes in structure thus effected
have led to corresponding modifications in the
work which these structures perform, the move-
ments of the advancing orders of animals thus

.37

58 Instinct and Intelligence

becoming adjusted to their environment. In
the following pages we shall show this adapta-
tion between structure and instinctive processes
in those classes of beings which succeed the
Hydromedusa in the ascending scale of

animals, viz., the
Echinodermata, in-
cluding star-fishes ;
the Annelida, to

which
long;

worms be-
and lastly

the Arthropoda,
including crus-
tacea, such as cray-
fish and insects.
A typical star-

FIG. 8. — Diagram of the nervous system fjgj} (Fi°" 8) DOS-
of a star-fish, a, central nerve-ring sur-
rounding the mouth ; b, peripheral SCSSCS a Central
nerves of the arms.

body from which

five radiating arms extend outwards; on
their upper surfaces are numerous cal-
careous nodules supporting short spines.
Between these nodules there are a number
of processes or stems terminating in
pincer-like structures, worked by muscular

Star-fish 5 g

action.1 The under surface of a star-fish's
body has an opening or mouth leading to
the gullet and digestive organs, from
which there is an outlet on the upper part
of the body. The under surface of each
arm is grooved, and has rows of contractile
tubular organs each terminating in a sucker,
known as the "tube feet." These structures
are worked by the contraction and relaxation
of the muscular fibres which surround the tube,
and are thus under the control of the animal's
nervous system.

The nervous system of a star-fish is derived
from and is in close connection with the proto-
plasmic elements of the ectoderm. The central
part of this system is composed mainly of two
rings of nerve cells and fibres which surround
the animal's gullet. From these circum-oral
rings radial nerves extend throughout the
length of each of the animal's arms ; they supply
branches to its entire muscular system, and
also to the sensory organs. In addition to the
radial system of nerves, although doubtless

1 Jelly-fish, Star-fish, and Sea-urchins, by G. J. Romanes,
P- 255-

60 Instinct and Intelligence

intimately connected with it, a plexus of nerve
cells and fibres exists beneath the ectoderm,
corresponding to that found on the under sur-
face of the swimming-bell of Medusoids.1

The sensory organs of a star-fish are derived
from the ectoderm, and consist of an abundance
of tactile organs situated on the spines and
pedicels of the animal's arms; in some species
of star-fish a bright red spot exists on the ter-
minal tentacles of each of the five arms, which
indicates the position of the animal's visual
sensory organs, these are of a higher order
than those we have referred to as the eye-spots
of unicellular beings and o'f Medusoids. The
outer surface of the visual organs of Echino-
derms is formed of one or more layers of trans-
parent cells, and beneath this layer a refractive
lens-like structure rests on a mass of deeply
pigmented cells. In connection with these
colour-bearing cells, club-shaped nucleated
cells may be demonstrated which receive at
their base fibres from terminal branches of a
radial nerve; in this way a communication
is established between the animal's visual

1 Romanes on Jelly-fish, p. 292.

Sensory Organ of Star-fish 61

organs and its circum-oral or central nervous
system.

With reference to the instinctive behaviour
of Echinodermata, an ordinary star-fish is able
by the use of one or more of its arms and sucker
feet to hold on to the bottom or to the sides of
its tank; the muscles of the arm then contract
and draw the animal's body up to the point its
feet have grasped ; it thus moves forward, either
along the bottom or up the side of the tank.
When a star-fish reaches the surface of the
water it comes to a stand, as its sucker feet can
only act efficiently beneath the water. Under
these conditions a star-fish stretches out its
uppermost arms along the surface of the water
so as, if possible, to meet with something it can
cling to; if it succeeds in doing this, it relin-
quishes its hold on the side of the tank and
swings itself on to the object it has grasped.
Mr. Romanes remarks with regard to behaviour
of this kind that the activity and co-ordination
manifested by the animal's acrobatic move-
ments are surprising, and have almost an intel-
ligent appearance.1

1 Romanes on Jelly-fish, p. 269.

62 Instinct and Intelligence

As the sucker feet of a star-fish are only
found on the under surface of its arms, the
animal, if turned over on its back upon a flat
surface, is unable to secure a fixed hold by
which to drag its body into its natural position.
In these circumstances the animal inverts the
tip of one or more of its arms until some of its
feet can gain a hold on the surface upon which
it has been placed ; from this fixed point the
animal turns over so as to regain its normal
position.

If a star-fish is moving in a certain direction
and one of its foremost arms is pricked or
pinched, the animal instantly reverses its
course, apparently with the object of escaping
from further injury. A hungry star-fish will
follow food moved slowly from one to another
part of its tank; if it succeeds in grasping the
food, it is carried to its mouth, the other arms
of the animal, if necessary, coming to assist in
this action.

So long as a star-fish's organs of vision are in
working order the animal evinces an inclination
to move towards and remain in the light; but
if these organs have been destroyed move-

Movements of Star-fish 63

ments of this kind are hindered or altogether
abolished. If both the visual and tactile sen-
sory organs of one of these animals are removed
the creature ceases to move, but if fed it may
continue to live.

Although it is difficult for star-fish to move
from one place to another unless by means of
their sucker feet, it is possible for them to
shuffle along when placed on their backs. They
accomplish this movement by aid of their
pincer-like spines, which under these conditions
act together in a remarkable manner so as to
push the animal along in a continuous direc-
tion. If while progressing in this manner a
lighted match is held near the animal, as soon
as the heat reaches it the whole of its spines
reverse their movement, and work in the oppo-
site direction.

Movements similar to those above referred
to take place in the recently amputated arm of
a star-fish. They are distinctively purposive in
character, and depend on energy set free by
external stimuli acting through sensory organs
on the sub-ectodermal plexus of nervous
matter, to which we have referred. In a short

64 Instinct and Intelligence

time after an arm of a star-fish has been am-
putated, its circulation and consequently meta-
bolic processes cease, and with this change the
potential energy of the nerve cell fails, and all
instinctive or any other movements of the am-
putated arm cease. If the sensory organs of
an amputated arm are removed, or if they are
not appropriately stimulated the limb remains
motionless.

From experiments made on various species
of living star-fish we learn that the function
performed by its central nervous system is to
bring about the co-ordinate working of the arms
and various parts of its body in a purposive
manner. If the circum-oral rings are removed
the animal completely and permanently loses
all power of co-ordinating its arms or their
sucker feet.

The result of excision of the sensory organs
of jelly-fish and star-fish leads us to conclude
that the exciting cause of the animal's instinc-
tive behaviour depends, to a large extent, on
work performed by these organs; for if they
are destroyed all such action is abolished,
although the animal may continue to live. This

Behaviour of Hydroids 65

means that the prompting cause of purposive
action is energy derived from external or
internal sources acting through sensory organs,
which, by practice have become sufficient to
provide for the necessities of the classes
of animals we have referred to in their
struggle for existence, and for their repro-
duction.

Professor Preyer informs us that on slipping
a piece of rubber tubing over the middle part
of one of the arms of a star-fish, belonging to
a species in which those members are very
slender, he found that the animal tried succes-
sively various devices to get rid of the foreign
body ; by rubbing it against the ground, trying
to shake it off; holding the tube against the
ground with a neighbouring arm, and finally,
as a last resort casting off the limb together
with its rubber ring.1 Action of this kind is
probably due to the overflow of nervous energy
set free by the stimulus excited by the pressure
of the rubber tubing on the sensory organs of
the limb. Most people, however, refer these
movements to "spontaneous action/' which is,

1 .The Animal Mind, by Margaret F Washburn, p. 215.

E

66 Instinct and Intelligence

at best, as Prof. Huxley remarks, a term em-
ployed "when we do not know anything about
the -cause of any phenomena." It would be
well for science if we could rid ourselves of
such phrases, for modern scientific ideas can
accept no theory which is not founded upon
continuity of phenomena, whether physical or
psychical.

The bodies of jelly-fish and star-fish have
neither a head nor tail, neither right nor left
side, an arrangement which is sufficient to meet
the needs of beings whose food is brought to
them floating in the water by which they are
surrounded. But when from geological or other
changes in their environment animals of this
description have been compelled to pass from
an aquatic to a terrestrial mode of life, and
therefore to search for their food, or for a mate,
and to protect themselves from enemies, the
various kinds of protoplasm constituting the
basic substance of the structures of the " fittest "
of these beings must have responded ade-
quately to the incidence of the forces acting on
them, and thus gradually developed a nervous

1 Huxley's Essays, p. 216, Everyman's Library Edition.

The Origin of the Brain 67

system and sensory organs which enabled them
to meet the demands of the conditions to which
they were exposed.

The class of beings (Vermes) which include
the various orders of worms follow the star-fish
in the natural ascending classes of animals; of
these we may refer to the common earth-worm
to illustrate the link which exists between the
structural development of a central nervous
system, and the growth of instinctive processes.
It is probable that earth-worms have been
developed from fresh-water, and these from
marine, ancestors.1 When these animals came
to dwell on the land they must have begun to
move with one part of their bodies in front, and
thus acquired an anterior end or head, and sides
to their bodies. The head of the organism
being thus brought into constant contact with
external objects, its sensitive elements, includ-
ing nerve cells connected with its skin layer,
were developed by use, and at the same time
became protected by passing from the surface
deeper into the head; in this way an aggrega-

1 Comparative Anatomy of Animals, by Gilbert C. Bourne,
Vol. II., p. 43

E 2

68 Instinct and Intelligence

tion of nervous matter was effected, forming

an organ which we recognise as the animal's

brain.

The body of a large earth-worm contains a

series of from 100 to 200 segments or somites,

each of which is fur-
nished with four pairs of
bristles or chaetae mov-
able by muscles, and con-
stituting the animal's
chief locomotory organs.
An earth-worm's mouth
is situated on the under
surface of its head; at
the posterior extremity
of its body is a terminal
opening or anus. The
nervous system of these

medio-dorsal nerve tracts. worms consists of tWO

masses of nerve cells and fibres (ganglia)
situated just above the passage leading from the
animal's mouth to his stomach (Figs. 9 and 10).
These ganglia give rise to the nerves passing
forwards to the head and to a ganglion situated
below the gullet, from whence a cord of

FIG. 9. — a, cerebral ganglia ;
b, mouth ; c, ventral nerve

77. C.

The Nervous System of Worms 69

nervous matter extends along the length of
the body; at each somite the cord swells
into a ganglion from which nerves pass
t o neighbouring
structures. These ;;

nerves contain in-
coming (afferent)
fibres or paths, by
which impressions
made on the surface
of the animal's body
are conducted to the
central ganglion,
and outgoing fibres
(efferent) commenc-
ing in the ganglion
and terminating in
effective structures
such as muscles or
glands. The class

0 FIG. io.— Diagram of nervous system

of beingS tO Which of Annelida. 5, brain ; c.n., cephalic

nerves to supply sense organs of

5 belong, anterior end of the worm ; n.c., nerve

1 cord passing from the brain to s.e.g.,

US not Only the sub-cesophagoal ganglion ; s.g.,

1 r U segmental ganglia giving off nerves

an example OI the to the corresponding segments of the

, . , , bodv. (Human Speech, Fig. 30,

way in which their p. I26.)

70 Instinct and Intelligence

sensory organs have been evolved by natural
modes of energy acting on differentiated
living matter, but they also illustrate the
gradual loss of these organs when deprived of
their appropriate modes of stimulation. For
instance, some aquatic worms have visual
organs, but in the common earth-worm, living
as it does without sunlight these organs have
disappeared. But although these animals do
not possess eyes, when the anterior ends of
their bodies are exposed to a stream of bright
light the worm speedily retreats into its burrow,
while if other parts of the animal's body are
alone illuminated it remains perfectly passive.
It would seem that the energy attached to
waves of light affects the ending of cutaneous
nerves of the animal's head, and reaches its
cerebral ganglia, thus setting free some of their
latent purposive energy, which becomes mani-
fest in the co-ordinate action of certain groups
of muscles, and so to instinctive movements of
the animal's body. Some fishes and reptiles
are influenced by light which falls on the skin
alone ; a frog whose eyes have been removed
will, if light of suitable intensity be allowed to

Instinctive Behaviour of Worms 7 1

fall on the animal, turn its head and jump
towards the source of light.

There is a great contrast between the more
prominent instinctive movements displayed by
worms, and those of beings which possess
neither head nor tail, their central nervous
system consisting of two subdermal rings of
nerve cells and fibres, in place of a rudimentary
brain such as that which exists in the head of
an earth-worm. For example, the common
earth-worm displays remarkable purposive be-
haviour in the way it plugs the external opening
of its burrow. The animal emerges from its
burrow at night, and drags dry leaves, the petals
of flowers, paper, or other light materials,
squeezing them into its burrow. A leaf when
being dragged to the burrow often becomes
folded or crumpled. When another leaf is
drawn in, this is done exteriorly to the first one,
and so on with the succeeding leaves; and
finally they all become closely folded and
packed together; the interstices between the
leaves being filled up by means of a viscid
secretion ejected from the animal's body.
Darwin describes the way in which an earth-

72 Instinct and Intelligence

worm almost invariably lays hold of leaves by
their tips, so that the thin part of the leaf can
be easily drawn into the burrow, leaving the
thick foot-stalk projecting outwards from the
mouth of the hole. He observes : " Although
the habit of dragging leaves into their burrows
is undoubtedly instinctive with worms," never-
theless these purposive movements are so
accurately adapted to fulfil their ends, that it
is difficult to distinguish them from movements
guided by intelligence.1

Darwin refers to the fact that the instinctive
behaviour of earth-worms is hereditary, for he
had watched a very young one born in one of
his pots, dragging for some distance a Scotch fir
leaf, one needle of which was as long and almost
as thick as its own body. No species of pine
was endemic in the part of England where this
incident occurred; it is therefore incredible
that the proper manner of dragging pine-leaves
into the burrow could have been learnt by this
worm ; its behaviour was clearly instinctive or
innate, for so young an individual could not

1 The Formation of Vegetable Mould, by Charles Darwin,
pp. 27, 56.

The Brain and Nervous Energy 73

have carried out a series of movements such as
those referred to as a result of its own experi-
ence; the only kind of action which Mr.
Romanes believes can be accepted as an indica-
tion of intelligence.1

The burrows of the ordinary earth-worm are
carefully lined by leaves and earthy materials,
and terminate in a chamber in which one or more
worms pass the winter rolled up into a ball, kept
warm by the lining of the passage and the
effective plug they have constructed to exclude
external cold, and the danger of being flooded.

It thus appears that with the development of
a brain or aggregation of nervous elements in
the head of a class of living beings, their
instinctive behaviour rises to a higher level
than that displayed by more lowly organised
animals. This state of things can be under-
stood, if we admit that the functions performed
by certain of the elements of nervous matter is
to transform energy acting on it into instinctive
processes. The evidence we have thus far
advanced supports this idea, and, still further,
points to the fact that the purposive movements

1 The Formation of Vegetable Mould, by Charles Darwin, p. 90.

74 Instinct and Intelligence

of the animals we have referred to are propor-
tionate to the completeness with which the
protoplasmic elements of their nervous system
has responded to the divers modes of energy
acting on it, that is to the environment.

Passing from the Annelida to the higher class
of the Arthropoda, which includes the Crustacea
and Insecta, we find the instinctive movements
of these orders of animals to be in harmony
with the ideas we have endeavoured to inculcate
in the preceding pages, which in our opinion
are competent to explain the phenomena in
question.

We may refer to the crayfish as representing
the Crustacea. These animals abound in many
of our streams and harbours; they are rarely
more than three or four inches long, and in
appearance are not unlike small lobsters;
they may often be seen walking along the
bottom of shallow streams by means of four
pairs of jointed legs.1 At other times a cray-
fish appears at the mouth of a burrow he has
excavated in the banks of a stream; he lies at
the entrance to his hole, barring it with his

1 The Crayfish, by T. H. Huxley, pp. 6, 9.

The Crayfish 75

claws and feelers, keeping careful watch on the
passers-by. Larvae of insects and tadpoles, small
frogs, and other objects which come within the
animal's reach are seized and devoured. In the
spring of the year female crayfish are found to
be laden with eggs attached to their tails ; when
hatched they give rise to minute young beings
which are sometimes seen hanging on their
parent's body, under whose protection they
spend the first few days of their existence.

Scattered over the surface of the body of a
crayfish there are a multitude of tactile sensory
organs, known technically as setae : they are
particularly well developed on the animal's
antennules or feelers. The setae arise from
cells of the ectoderm, and at their attached sur-
face receive terminal fibres which originate in
the nerve cells of the animal's mid-brain. On
the under side of the outer branch of the anten-
nule sensory structures exist, which there is
reason to think form part of an olfactory ap-
paratus. The eyes of a crayfish consist of
highly complex structures, arranged so as to
bring waves of light to bear upon the fore ends
of two bundles of optic nerve fibres; thus

76 Instinct and Intelligence

forming an apparatus which, as Huxley ob-
serves, sorts out the rays of light into as many
very small pencils as there are separate end-
ings of the fibres of the optic nerve, and in
part serves as the medium by which luminous
waves are converted into molecular nerve
changes. It is evident that the sensory organs
of crayfish are much more highly organised than
those of worms, or of any of the lower classes
of animals. Accompanying this increased com-
plexity of structural arrangement in these re-
ceptors of energy is an increased development
of the cerebral nervous centres, or areas from
which the nerve fibres supplying these organs
originate. Fig. n is a drawing made from a
section of a crayfish's brain, showing its
anatomical division into anterior, middle, and
posterior sections or lobes.

The brain gives off fibres which form the
optic and antennary nerves, as well as the
nerves which supply the viscera and certain
muscular structures. The sensory organs are
in close connection with the nervous matter of
the animal's mid-brain, which seems to exercise
a controlling influence over the rest of the

Brain of Crayfish 77

cerebral system, and thus over the behaviour of

the animal.

0.0.

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T. c.

FIG. n. — Horizontal section through the brain of a crayfish,
x 40. C.C., corpus centrale ; C.GB., commissure of globuli ;
C.PC.L., commissures of protocerebral lobes; DC., mid-brain;
GB., globulus; GL., glomeruli ; G.N., ganglionic nuclei; O.D.,
decussating bundle of optic tract ; O.T., optic tract ; PC.L., fore-
brain ; T.C., hind-brain. (Cat. Physl. Series, Museum Roy. Coll.
Surgeons, Vol. II., p. 22.)

As a consequence of the more complex
structural arrangement and development of the
central nervous system, and sensory organs in

7 8 Instinct and Intelligence

crayfish than in earthworms, the ordinary in-
stinctive movements of the former animals are
of a distinctly higher order than those displayed
by the latter. For instance, a crayfish with its
head, claws, and long feelers protruding from
its burrow keeps a careful watch on the divers
objects floating near it in the surrounding
water, and whatever these may be, they are
seized by the animal's claws, torn to shreds by
its capacious jaws, and passed into the
creature's mouth. It is said these animals even
devour their own spouses. Crayfish exercise
no discrimination in the choice of their food ;
anything floating within its reach acts as a
stimulus on the animal's visual nervous system,
a stimulus which becomes manifest in the pur-
posive movements of certain groups of muscles,
leading to the effective grasping of the object
which set the neuro-muscular machinery in
action. The adjustment of such movements to
the incidence of external stimuli is doubtless
facilitated by the excitation of the animal's
tactile sensory organs or setae which abound on
his antennae. These feelers are constantly
waving about in the surrounding water, and are

Instinctive Behaviour of Crayfish 79

thus liable to come in contact with floating
bodies, causing a discharge of some of the
potential energy of nerve cells of the brain, and
thus bringing about the contraction of the
muscles controlling the use of the animal's pre-
hensile organs.

Professors Thorndike and Yerkes have done
much good work in testing the instinctive re-
actions of certain of the lower animals, by what
is known as the labyrinth method. This plan
consists in ascertaining the facility with which
an animal learns the correct road to take through
a labyrinth, interposed between its home and its
food. In the case of crayfish, a labyrinth offer-
ing only a single choice of passages was placed
between the animal's aquarium and its food.
" About half-way down the interposing box a
partition, put in longitudinally, divided it into
two passages, one of which was closed at the
end by a glass plate. In sixty trials the animals,
which had originally chosen the correct passage
50 per cent, of the time, came to choose it
90 per cent, of the time. A second series, with
a single animal upon which more tests a day
were made, resulted in the formation of a per-

80 Instinct and Intelligence

feet habit in 250 experiments. The glass plate
was then shifted to the other passage, and the
crayfish was naturally completely baffled for a
time, but ultimately succeeded in learning the
new habit." l

From these and similar experiments it is
evident the functions performed by the nervous
matter constituting the lines of communication
between sensory organs, nerve centres, and their
efferent fibres improve by use. Thus the pur-
posive movements of the crayfish, after the
animal had been subjected for a number of
times to the same form of stimulus, became so
perfect that other less energetic stimuli failed
at the moment to elicit a response, or to influence
the behaviour of the animal. Movements of
this kind are often ascribed to experience
gained by the animal during repeated trials to
attain desired or pleasurable ends. Mr.
Romanes was of opinion that we can only infer
intelligence in an animal when we see the
individual profit by his own experience. But
what is the meaning to be attached to the terms
experience and intelligence? Behaviour, when

1 The Animal Mind, by M. F. Washburn, pp. 220, 319, 323.

Intelligence and Experience 81

the result of personal trial or experience, is
attributable to the re-excitation of impressions
made by repeated similar kinds of stimuli on
the mnemic elements of nerve cells. Intelli-
gent behaviour involves the modifications in the
action of those elements which constitute the
agency by which instincts become manifest.1

Among invertebrates, instinctive movements
have reached their highest point of perfection
in ants and bees, and we find a corresponding
development of their central nervous system,
for if there is one organ of the body more than
another which increases in complexity as evolu-
tion proceeds it is the brain.

The central nervous system of insects con-
sists of a brain and a chain of ganglia extending
along the ventral part of the animal's body,
which in many instances are found to have
undergone concentration longitudinally. From
this chain of nervous matter sensory and motor
nerves pass to the structures forming the
animal's body; it is continued upwards into
the lower brain.

1 Psychology, "The Study of Behaviour," by William McDougall,
F.R.S., p. 164; also "Instinct and Experience," by Prof. Lloyd
Morgan, pp. 7, 9, 12, 27, 32.

82 Instinct and Intelligence

The fore-brain in insects is formed by the
optic ganglia together with two masses of
nervous substance united by communicating
fibres. In connection with these lobes we find
aggregations of small granule nerve cells from
which fibres pass to the mid-brain. Similar
masses of nerve cells exist in the brain of the
sea-mouse, and are more highly developed in
crayfish (Fig. n, G.N.), but they attain their
highest state of perfection in insects. For
instance, in the working bee nervous structures
of this description form two masses, situated
near the dorsal surface of the brain. Within
the same order of beings these structures
increase in size in proportion to what we judge
to be the instinctive capabilities of the animal,
they are larger in the worker than in the drone
or the queen bee.1

The mid-brain or antennary lobes of insects
consist of two masses of nerve cells united by
bands of communicating fibres. From this part
of the brain nerves pass to the antennae; it is
also the meeting-place of nerve fibres proceed-

1 Mr. R. H. Burne, Catlg. Phys. Series of Compa. Anatomy,
Royal Col. Surgeons Museum, p. 35.

Origin of Basal Ganglia 83

ing to and from the various sensory organs of
the animal's body. The mid-brain, therefore,
of crayfish and of insects corresponds to that
part of the brain of vertebrates to which we
shall subsequently refer as their basal ganglia.

The hind-brain of insects gives off nerves to
supply the animal's alimentary canal ; it forms,
as it were, the head of the chain of ganglia
alluded to in our description of the central
nervous system of crayfish.

We may now turn our attention to the sensory
organs of insects, which consist of structures
derived for the most part from the ectoderm,
specially modified either in the form of single
or groups of cells, which act as the receptors of
energy derived from visual, olfactory, and tac-
tile impressions.1

The visual sensory organs of insects consist

1 "It is probable the structures of the various sensory organs
that first receive the external stimulus act like a sieve, arresting
certain qualities of the exciting energy and permitting certain other
qualities to pass on, so as to act on the specialised living nervous
substance of the various sensory centres. These receptors of energy
have thus a certain power of selection or natural fitness developed
by means of the action of their environment or struggle for
existence." — (Professor T. Ziehen, Introduction to Physiological
Psychology, pp. 40, 42.) As we have shown, after leaving a
sensory organ by nerve paths energy becomes subjected to further
selection through the action of an interrupted system of dendrons,
so that by the time it reaches the living matter of the correspond-
ing cerebral cell it has assumed a specific form.

F 2

84 Instinct and Intelligence

of many eyes, each with its own retina and
dioptric apparatus separated from its neigh-
bours by pigment-cells.1

The visual power of these beings depends
largely on the form and the number of facets
possessed by the outer surface of their eyes;
for instance, the prominent convex eye of the
dragon-fly is said to contain from 12,000 to
17,000 facets. We can form an idea of the
acuteness of vision possessed by these insects
if we try to catch one of them when hovering
over a pond. The dragon-fly will allow us to
approach our net just near enough to miss
catching it, when off he darts, seeming able to
measure the length of the handle of our net,
for the insect repeatedly flies oft in spite of
our efforts to capture it. Wasps can judge the
size and colour of inert objects by the aid of
their eyesight. Thus if some dead flies are
placed together with other insects on a table in
a room where there are wasps, a wasp will soon
fly down and without hesitation alight on a dead
fly, which he will carry off, and this process is

1 R. H. Burne, Asst. Curator, Roy. Coll. Surgeons of England,
Cat. K.C.S. Museum, Physiol. Series, Vol. III., p. 302.

Sensory Organs of Insects 85

repeated over and over again without the wasp
taking any notice of the surrounding dead
insects.

The olfactory sensory organs of insects con-
sist of structures adapted to receive and trans-
mute a special form of energy into one which,
on reaching certain cerebral centres, becomes
manifest in the sensation we designate odour.
By the sense of smell, therefore, we mean the
response made by a specialised system of living
matter to definite modes of energy derived from
certain bodies.1 The olfactory sensory organs
of insects are located on their antennae among
the tactile setae; they are supplied by terminal
branches of the antennary nerves which arise
from nerve cells located in the animal's mid-
brain.

The different genera of ants, which under
ordinary conditions are natural enemies and
fight to the death when they meet, after
having had their antennae excised may be kept
together in the same box, where they live on

1 There are hardly any metallic or other bodies which do not
manifest, especially on friction, odour of their own. Berthelot
calculates that one gram of iodoform only loses the hundredth
of a milligram in a hundred years, thcugh continuously emitting
a flood of odoriferous particles in all directions.

86 Instinct and Intelligence

friendly terms. Having no antennae, and there--
fore no sense of smell, they can no longer dis-
tinguish friend from foe. Male insects after
their antennae have been removed do not recog-
nise the female; they will pass close to their
favourite food without noticing it; they guide
themselves by the sense of smell, and when
their antennae are removed fail to retrace
their way home from a distance or to recognise
their companions when they reach their
nests.1

If an ant is smeared with matter pressed from
the bodies of its nest companions, and then put
back among the latter, they take no notice of
the stained insect. But if an ant is smeared with
fluid pressed from the bodies of a hostile nest,
and then returned among its companions they
at once attack and kill it. Evidently it is the
odour of the fluids in the two cases which affects
the actions of the ants through impressions made
on their olfactory sensory organs, impressions
which pass through the antennary nerves to the
olfactory lobes of the insect's brain and re-

1 The Senses of Insects, by A. Forel, translated into English
by Macleod Yearsley, F.R.C.S., pp. 69, 129.

r Olfactory Organs of Insects 87

excites those previously established in its
nervous substance.

In order to substantiate the fact that the
organs of smell are located on the antennae of
flies and other insects, we may refer to one
among the numerous experiments which Mon-
sieur Forel has made. He placed the body of
a decomposing mole under a hemispherical
wire gauze cover. A fly soon arrived and tried
to gain access to the dead animal. Forel caught
the fly, and after destroying its eyes let it go.
The insect flew about the room knocking itself
against the ceiling and walls, and finished by
falling on the floor in a helpless state. Forel
then removed one of the fly's wings, and after-
wards placed it near the mole, which he un-
covered ; the fly immediately set to work to feed
on the dead animal. He then removed the
insect's antennae ; from that moment, despite
oft-repeated trials, the fly paid no more atten-
tion to the mole than to a piece of stone or a
bit of wood.

Taste. — Insects as a rule possess the power
of distinguishing between the quality of certain
non-volatile substances before swallowing them.

88 Instinct and Intelligence

For instance, if morphia or strychnine is
mixed with honey, ants attracted by the smell
of their favourite food begin to eat the mixture,
but after taking it into their mouths they leave
the tainted honey. When the antennae and palpi
of wasps were removed and the animal's mouth
then brought in contact with honey mixed with
quinine, after tasting it the insect immediately
turned away from the honey. From experi-
ments of this kind it appears certain that in
insects the sensory organs of taste are located
within the animal's mouth, and consist in all
probability of a series of cup-like depressions,
connected with the terminal distribution of
subjacent fibres proceeding from nervous
centres located in the subcesophageal ganglion
and the mid-brain.

Touch. — The sensory organs of touch in
insects consist of structures similar to those
described as existing in Hydroids (p. 37).
They are scattered over the surface of their
bodies, and are well developed on their
antennae.

Hearing. — With the exception of crickets
and a few other insects, there is no evidence to

The Memory of Insects 89

show that this class of animals possesses the
sense of hearing.

From the preceding statement it is evident
that insects possess visuo-sensory and olfactory
organs, also sensory organs of touch, taste, and
the muscular or kinaesthetic sense; some few
of them have the power of hearing. Leading
directly from each of these receptors of energy,
nerve fibres pass to corresponding nervous
centres located in the brain. These cerebral
nervous centres are in intimate communication
with one another by means of protoplasmic
fibres, and the whole of this system of sensory
organs and cerebral centres is brought into
close relation with the nervous matter of the
mid-brain.

That insects possess memory is demon-
strated by their actions. For instance, Professor
J. Loeb states that there was a wasp-hole in a
flower-bed in his front yard. Towards noon he
saw a wasp passing along the side walk of the
street in front of his yard, carrying a caterpillar
in its mouth ; the weight of the caterpillar pre-
vented the wasp from flying. The yard was
separated from the street by a cemented stone

go Instinct and Intelligence

wall, up which the wasp repeatedly made an
attempt to climb, but kept falling back. The
insect, failing to scale the wall, then ran round
the bottom of it until it reached an opening,
through which it crept into the yard. Then
crawling through the fence which separated the
two yards, it dropped the caterpillar near the
root of a tree and flew away. After a short
zigzag flight it alighted on a flower-bed in which
were two holes. The wasp soon left the bed
and flew back to the tree, stopping twice on
the road. It then landed on the caterpillar it
had left and dragged it into its hole, which it
covered with sand.

As an example of instinctive processes in
insects we may refer to the slave-making ants
which are incapable of tending their young, and
even of feeding themselves. At a particular
period of the year, when the nests of the black
ants contain the neuter brood, at a given signal
made by certain of the leaders of a nest of red
ants, an army of these insects leave their nest
and advance in fairly straight lines, the van-
guard, which consists of eight or ten ants, con-
tinually falling back to the rear. In some cases

Instinctive Behaviour of Ants 91

the whole army separate in search of nests of
black ants. At last a nest of these latter species
having been found, a signal is given by striking
the forehead of a neighbour; this signal is
passed from one red ant to the other, and the
army re-forms. On arriving at the black ants'
nest a desperate conflict ensues, which ends in
the defeat of the negroes; and the red ants
then enter the nest and leave it almost in-
stantly, each insect holding a larva or pupa in
its mandibles, which it carries home with all
speed. In the return of the army there is never
any hesitation ; the olfactory and visual memory
of the outward journey is sufficient to make
known to each ant the exact road. Having
reached home the red ant hands over the stolen
larva to a slave, and as a rule sets off imme-
diately to the pillaged nest if it still contains
more larvae, or they may put off the return
journey until the following day. Forel states
this return journey is never made if the pillaged
nest has had the whole of the larvae removed;
he remarks : " The fact appears to me to fur-
nish irrefutable proof of their memory. They
must remember if the pillaged nest still con-

92 Instinct and Intelligence

tains pupae or not; that is to say, if there are
many or few. Neither reflexes, nor odour, nor
polarised tracks can explain the thing." The
stolen pupae are treated by the red ants with
great care, and when grown up spend their lives
in excavating passages, collecting food, carry-
ing larvae, etc., for their masters as if this had
been their original destination; in fact, they
fulfil the office of slaves.

Bees appear capable of receiving and com-
municating to their companions impressions
derived from other bees. Thus if a queen bee
is removed from her hive, the workers soon miss
her and raise a prolonged and plaintive sound.
The queen bee, having been secured, was
placed in a wire case and returned to the upper
tier of the hive. The working bees im-
mediately changed their note from a doleful
into a joyful sound, which was taken up
and repeated by bees in the most distant
part of the hive. When about to swarm,
before the queen is allowed to leave the
hive, scouts are sent out to seek for a suitable
locality for the swarm to settle in. After having

1 Forel, p. 239.

Nervous Energy and Brain 93

chosen a spot the scouts return and conduct the
swarm to the place they have selected, showing
not only a memory of places, but also remark-
able instinctive power, if not intelligent action,
in their movements.

From this series of observations and experi-
ments it is evident that the purposive move-
ments of insects are brought into play by
means of external and internal modes of energy
passing through the various sensory organs to
corresponding nervous centres constituted of
cells, a part of whose living matter contains
mrposive and mnemic elements. We also
learn that automatic processes effected by a
system of this kind are sufficient to maintain the
existence and reproduction not only of insects,
but of the whole kingdom of Invertebrates. It
has been shown that the behaviour of this vast
mass of the lower orders of animals is con-
trolled by instinctive action.

CHAPTER IV

Nerve cells and nerves — Spinal cord — Motor and
sensory nerves — Reflex action — The brain — The
Amphioxus and its nervous system — Fish — The
Lamprey and its brain — The basal or instinctive
ganglia — The development of the cerebral cortex —
The Mud-fish — The Stickleback, Salmon, Perch,
instinctive processes of, shown in traits of char-
acter— Their existence depends on presence of basal
ganglia — Amphibians, brain of — Location of centre
of instinctive movement — Reptiles, sense organs
of— Birds.

IT has been shown above that the effective
working of the living substance forming the
body of a nerve cell depends on its metabolic
properties, whereby the cell is kept primed with
working energy. One of the functions of these
charged elements is to respond to the streams
of energy which reach them through sensory
organs, and to transmute this energy into pur-
posive instinctive action. Automatic action
of this kind is all that is necessary for the pre-

Nerve Cells 95

servation and reproduction of invertebrates and
the three lowest classes of vertebrates ; it often
reaches so high a level that it is difficult to dis-
tinguish it from acts commonly attributable to
the work of intelligence. In the following
pages the origin and mode of action of a form
of nerve energy which is capable of infusing
intelligence into instinctive processes will be
explained.

Nerve cells consist of a minute mass of
nucleated protoplasm. From the body-
substance of the cell fibres of two kinds extend
outwards; one set of these fibres soon after
emerging from the cell divides into several
branches, which either unite or come into rela-
tion with similar fibres from neighbouring cells ;
these fibres are called dendrites or dendrons.
Other fibrils passing from the nerve cell con-
stitute what is termed its axis cylinder; these
fibres often extend for a considerable distance
from the cell in which they take their origin,
and in their passage through the brain and
spinal cord give off branches to other cells, and
ultimately break up into a plexus of fibrils
which are distributed to muscle cells or other

96 Instinct and Intelligence

effective struc-
tures. Soon
after leaving its
cell the axis
cylinder be-
comes encased
by an inner
sheath of fatty
matter, and an
outer sheath
known as its
neurilemma ; it
is along the
central axis or
conducting core
of the fibre
that impulses
travel to and
leave the body
of nerve cells.
Until the axis
cylinder of a
nerve cell has,
in the course of its development, become en-
closed in its protecting sheaths (or, technically,

— t

FIG. 12. — Diagram of a ganglionic
nerve-cell (neuron), d d d, dendrons ;
n, nucleus and nucleolus ; a.c, axis-
cylinder ; m, medullary sheath ; s, neuri-
iemma ; t, terminal branches. (Human
Speech, p. 147.)

Central Nervous System 97

myelinatcd) it is functionally imperfect as a
conductor of nervous energy. (Fig. 12.)

The central nervous system of vertebrates
consists of the spinal cord and brain ; the former
is enclosed in the vertebral column (backbone)
and the latter in the skull. The spinal cord is
formed of a cylinder of nervous substance
extending throughout the length of the spine;
it has a deep fissure in front and another behind,
the two halves of the cord being connected by
a strand of nervous substance which contains a
canal extending throughout the length of the
cord, and continued upwards into spaces in the
interior of the brain. Each half of the spinal
cord is divided longitudinally into three
columns, by the line of attachment of two
parallel series of filaments which constitute the
roots of the spinal nerves. If the anterior root
fibres are irritated the muscles to which these
fibres are distributed contract, but no pain is
felt; this is therefore known as a motor root.
If the posterior roots are irritated pain is felt,
referable to the area of the skin to which the
nerve fibres of these roots are distributed; the
posterior spinal roots are therefore known as

G

98 Instinct and Intelligence

being sensory in function. An irritant applied
to parts of the skin containing tactile organs
travels along sensory or afferent nerve fibres to
corresponding central nerve cells, thus releas-
ing a part of their potential energy which
extends to a motor cell, and thus reaches
muscles or other structures to which the motor
fibres are distributed, becoming manifest in a
definite kind of work. A system of this kind
is known as being a nervous arc ; when stimu-
lated it gives rise to what is termed reflex
action^ which, though strictly automatic, is
generally adapted to promote the well-being of
the organism.

The spinal cord after entering the skull
expands to form the hind-brain; this is pro-
longed upwards by means of strands of nerve
fibres into the "most constant portion of the
brain of vertebrates, the mid-brain." 1 (Figs. 1 1
and 13.) This latter part of the brain is con-
tinued onwards into the fore-brain. The cere-
bellum is situated above the bundles of nerve
fibres which connect the hind- and mid-brain.

1 The Nervous System of Vertebrates, by Prof. J. B. Johnston,
pp. 223, 261.

Telencephalon.
Diencephalon,

Mesencephalon.

Metencephalon.
Myelencephalon

Forebrain.
Interbrain.

Midbrain.

Cerebellum,

Medulla oblongata.

Medulla spinalis.

DIAGRAM FROM J. B. JOHNSTON'S Nervous System of Vertebrates.
FIG. 13. — A, the spinal cord, is prolonged upwards into B, the
medulla oblongata (myelencephalon). In this region the spinal
cord seems to widen out into a thin membranous roof covering the
central canal (fourth ventricle). The lateral walls of the medulla
oblongata contain aggregations of ganglionic nerve cells, which
form the nuclei or place of origin of some of the most important
nerves of the body. C. the metencephalon, forms a short section
of the brain, its roof is known as the cerebellum, the arms of
which encircle this section of the brain (Pons Varolii). D, the
Mid-brain (mesencephalon), consists of ventral and lateral walls
of nervous matter enclosing a narrow canal (Aqueduct of Sylvius).
Its dorsal walls form the two optic lobes. E, the Inter-brain
(diencephalon) constitutes, by means of its thickened lateral walls,
the optic thai ami ; the dorsal wall is also thickened at one point
by fibres which connect the two knot-like portions of nervous
substance known as the nuclei trabecuke. F, the Fore-brain (telen-
cephalon) consists of paired lateral lobes from the anterior end of
which processes pass to the olfactory lobes. A membranous roof
connects and covers the lateral lobes of the Fore-brain ventricle,
which divides anteriorly into a Y-shaped cavity and is continued
into the olfactory bulbs. The common cavity with that of the
inter-brain (diencephalon) constitute the third ventricle of the
brain ; the lateral or olfactory portions are comparable with the
lateral ventricles of the mammalian brain.
99

G 2

ioo Instinct and Intelligence

The term cerebrum is applied to the largest
section of the brain; it consists of the two
halves into which the fore-brain is divided,
known as the cerebral hemispheres, united to
one another by connecting nerve fibres.

In the Amphioxus, a small fish-like being, we
have an example of a living primitive verte-
brate. These animals inhabit shallow seas in
almost all parts of the world; although fish-
like in appearance, they have neither the struc-
ture nor habits of a true fish.1 An elastic carti-
laginous rod (the notochord) extends throughout
the length of the body of an Amphioxus, giving
support to its muscular and other structures.
The animal's central nervous system is formed
of a thick-walled tube, nearly co-extensive with
the notochord. The bulk of the cord is made
up of longitudinal nerve fibres; it contains a
central canal, round which are nerve-ganglion
cells, some of them of considerable size. At
the anterior end of the cord the central canal
widens to form a space known as the cerebral
vesicle. The nervous matter constituting the

1 The Introduction to the Study of the Comparative Anatomy
of Animals, by Prof. Gilbert C. Bourne, Vol. II., pp. 173, 188.

Nervous System of Amphioxus 101

walls of this vesicle contains cells of a similar
character to those found in the grey matter of
the basal ganglia; they give off sensory fibres
which terminate in the epidermis of the anterior
end of the animal's body; otherwise an Am-
phioxus has no brain.1 Motor and sensory
nerves are given off in pairs from the central
nerve cord to each section of the animal's body.

An Amphioxus is able to swim through the
water by sinuous movements of its body; it has
no fins, head, or jaws. It habitually rests with
the greater part of its body buried in the sand,
its anterior end projecting into the water. In
this position the animal obtains nourishment
from minute organisms, drawn inwards by
means of a current of water created by a ciliated
apparatus surrounding its mouth. If alarmed
the animal buries itself in the sand.

The class of animals which in the ascending
scale succeeds that to which Amphioxus belongs
includes the Fishes, which are divided into two
main groups : first, those having a cartilaginous,
and secondly a bony skeleton; the former are
represented by lampreys, dogfish, and sharks;

1 The Introduction to the Study of the Comparative Anatomy
of Animals, by Prof. Gilbert C. Bourne, Vol. II., p. 282.

IO2 Instinct and Intelligence

among the latter are perch, sticklebacks, salmon,
and the mudfish.

The brain of a sea lamprey consists of a
slight enlargement of the anterior end of the
spinal cord accompanied by a corresponding
increase in size of its central canal, and its
partial transverse division into three spaces or
ventricles. Upon this foundation certain
excrescences have been developed in connec-
tion with the animal's sensory organs of vision
and smell.1

The walls of the hind-brain are slightly
thickened by the aggregation of nerve cells to
form the nuclei, or place of origin of the nerves
which supply the animal's respiratory, alimen-
tary, and circulatory organs. The hind-brain
passes forwards by means of bundles of nerve
fibres which extend into the walls of the mid-
brain ; above these fibres is a part of the brain
known as its cerebellum, which in cartilaginous
fishes is of small dimensions. The dorsal walls
of the lamprey's mid-brain are marked by a
longitudinal furrow which separates them into

1 Catalogue of Museum of Royal College of Surgeons of
England, Vol. II., p. 65.

Nervous System of Fishes 103

two lateral portions known as the optic lobes,
they receive fibres coming from the animal's
retina. The lateral walls of the mid-brain (or
more correctly the diencephalon) are known as
the optic thalami, in the substance of which
some of the fibres of the optic nerve terminate
together with numerous fibres derived from the
animal's olfactory lobes, and tactile sensory
organs.

The mid-brain is prolonged anteriorly into
the fore-brain, which in cartilaginous fishes
consists of paired lateral lobes known as the
cerebral hemispheres. These at the anterior
end are prolonged forward as slender cylinders
of nervous matter, terminating in the olfactory
bulbs, which receive fibres from the animal's
olfactory sensory organs. (Fig. 13.) The fore-
brain contains a cavity known as the third
ventricle, whose lateral walls are thickened so
as to form the two corpora striata; these, with
the optic thalami, constitute the stem of the
brain or its basal ganglia.1 The nervous matter

1 In a recently published article on the anatomy and physiology
of the corpus striatum, bearing specially on its motor functions,
Dr. S. A. Kinner Wilson remarks that, " from a consideration of
the anatomical data, obtained by experiments on apes, and known
to be in part, if not entirely, identical in man, it is clear the

IO4 Instinct and Intelligence

of these basal ganglia is all-important, in that
a large part of their living substance is formed
of inherited nervous matter, which under appro-
priate stimuli regulates the behaviour of the
lower classes of vertebrates; energy derived
from external and internal sources being trans-
muted by the elements of these centres into
instinctive movements. (See footnote.) The
behaviour of these lower classes of animals may
therefore be said to depend on the nature of
the structural arrangement and motion of the
elements forming the nervous matter of their
basal ganglia. In some invertebrates, such as
the Crustacea (p. 77), nervous structures exist
which control the instinctive movements of
these animals, and we shall find that similar
organs are present in the brains of amphibians,

corpus striatum is an autonomous centre ; in other words, whatever
its function, that function is exercised independently of the
cerebral cortex." — (Brain : A Journal of Neurology, May, 1914,
pp. 477, 482.) He adds, its nerve fibres become myelinafed com-
paratively early in fcetal life ; that phylogenetically it is a very
old structure consisting of the basal part of the fore-brain. Dr.
Wilson further observes that in fishes the corpus striatum is
comparatively simple in structure, but in function acts as a "minia-
ture brain " ;' in reptiles and birds there are additions, and in apes
and man it consists of a complex organ closely connected with
the optic thalamus "and beyond." Prof. Elliot Smith regards the
corpus striatum as that part of the original cerebral hemisphere
whereby impressions from sensory organs, are brought to bear on
the, nervous mechanism regulating an animal's movements, or,
in other words, its behaviour.

The Basal Ganglia 105

and throughout all classes of vertebrates, in-
cluding human beings; in fact, it constitutes
a kind of matter which has passed through long
ages of evolutionary changes, and has thus
assumed a form which when brought into play
becomes manifest in instinctive action. In the
higher classes of animals by appropriate treat-
ment, the structural arrangement and functions
of this part of the brain may be modified ; one
of the main objects of education is to effect this
purpose, and thus to improve the innate disposi-
tion or character of an individual.

Almost every part of the walls of a lamprey's
fore-brain contains nerve fibres proceeding
from the olfactory lobes, and terminating in
primordial cortical cells, "by means of which
smell impressions pass indirectly through the
intermediation of another part of the hemi-
spheres " l ; thus showing a disposition towards
the differentiation on the part of certain of the
nervous elements of the hemispheres of the
brain in this, the lowest genera of true verte-
brates. In the ascending classes of animals

1 Prof. Elliot Smith's Arris and Gale Lectures, reported in the
Lancet for January isth, 1910, p. 150.

106 Instinct and Intelligence

these pallial or cortical nervous elements
gradually become developed, and ultimately
assume the structural and functional character
of what is known as the neopallium. Nerve
fibres can be traced from these cortical cells, as
well as directly from the olfactory, visual, and
tactile sensory organs to the basal or instinctive
ganglia. Consequently, we find in the brain of
the most primitive class of existing true verte-
brates nervous structures whose main function
it is to elaborate instinctive processes; it also
contains elements having a tendency to become
differentiated into rudimentary pallial or cor-
tical nervous structures, which in the higher
animals are indispensable for the occurrence of
psychical processes.

The instinctive behaviour of a rudimentary
form of brain, such as that possessed by a
lamprey, is of a correspondingly low type.
This animal has a circular mouth armed with
numerous hard tubercles which serve as teeth,
by which the animal is able to hold on to the
body of its prey; its tongue acts like a piston
in its mouth, and enables the creature to draw
in as well as expel water through its gills, and

Psychical Nervous Centres 107

to respire while clinging on to another fish and
sucking its blood. Lampreys pass from the
sea up rivers during the summer months for
the purpose of spawning. Sharks form another
genera of cartilaginous fishes; their instinctive
behaviour is somewhat more pronounced than
that of the lamprey, for if attacked they will
defend themselves with great determination;
and it is well known they follow the same ship
at sea for many days, swallowing almost any-
thing thrown overboard. Many sharks are
ovoviviparous, while others produce eggs
having a long filament attached to them, which
is apt to become entangled in sea-weed and
held there until the egg is hatched ; the parents
do not appear to take any interest in their
young.

The brain of bony fishes affords a favourable
field for the study of the development of cere-
bral nervous structures, there being a marked
tendency for its living matter to become, as it
were, sorted out so as to perform distinct kinds
of work, and thus to reach a higher standard
of organisation than that attained by car-
tilaginous fishes. This tendency is marked by

io8 Instinct and Intelligence

the numerous connecting links established
between the different parts of the brain,
whereby energy coming from one part is
readily able to modify the activities of some
other part. This higher organisation of the
brain is effected by the extension, and constant
exercise of all the sensory paths leading from
the receptors of energy up to their correspond-
ing cerebral nervous centres, nature thus indi-
cating clearly the means that should be followed
in any attempt to develop the structural per-
fecting, and thus the efficient working of the
cerebral nervous centres and their associative
and mnemic elements.1

1 The gustatory apparatus in many of the bony fishes is well
developed, the terminal nuclei of its sensory organs being located
in the basal ganglia in association with those of the tactile,
olfactory, and visual organs ; a state of things tending to facilitate
the correlation of tactile, gustatory, and olfactory impulses, and
thus the control of the animal's movements for the capture of
food. (The Arris and Gale Lectures, by Prof. Elliot Smith, see
Lancet, pp. 169-174, for the year 1910.) The sensory organs of
taste in not a few bony fishes are scattered over the surface of
their bodies, and helps them to detect the presence of food. In
other fishes these organs are plentiful near their mouth, and are
used by these animals in search of food ; hence the differentiation
of the nervous matter constituting the nuclei of their cerebral
gustatory centres, the taste organs being located in the mouth of
terrestrial animals are rarely employed in their search for food.
This explains the relatively slight importance of the sense of taste,
and the comparative insignificance of its nervous apparatus in the
higher vertebrates as compared with their visual, auditory, and
other sensory nervous systems.

Development of Neopallium 109

The brain of the South American mud-fish is
an example of the highest state of development
reached by this organ in bony fishes ; the pallial
formation of its hemispheres contains a fairly
compact layer of cortical nerve cells, its
lateral extremities show signs of commencing
specialisation to form the pyriform lobes into
which olfactory tracts penetrate, and its mesial
extremity forms what are known as rudimentary
hippocampal lobes. Beyond this the grey
superficial strata lining the basal ganglia con-
tain a layer of pyramidal cells (the epistriatum) ;
which receives terminal fibres from various sen-
sory organs, and passes into, and possibly
constitutes an important element in the develop-
ment of the neopallium. But the cortical struc-
tures of the highest orders of fishes, as well as
those of amphibians and reptiles, can only be
taken as indications of the first stage of the
labour attending the birth of a true neopallium,
such as that which exists in the cerebral hemi-
spheres of the Mammalia.1

We may now refer to the instinctive be-

1 The Nervous System of Vertebrates, by Prof. J. B. Johnston,
pp. 255, 297, 310, Fig. 152. Also the Arris and Gale Lectures,
pp. 151-2, the Lancet, January 15, 1910.

no Instinct and Intelligence

haviour of the mud-fishes of Guiana, possess-
ing as they do a somewhat higher type of brain
than that of the cartilaginous fishes; it is
interesting to find the instinctive behaviour of
these animals is also of a superior character
to that displayed by any of the lower orders of
the same class of beings. For instance, the
mud-fish of South America is in the habit of
constructing a nest in the banks of the stream
it inhabits, which it makes from grass and the
leaves of water-plants. These it binds together
so as to form a secure place in which the female
can deposit her eggs. The male fish keeps
watch over the eggs, and the young fish until
they take to the water and begin an independent
existence. These fish travel for a considerable
distance over the land dividing one stream
from another ; during the dry season they bury
themselves in the bed of a stream, and remain
there until the return of the rains, which
soften the earth in which they have slept
and thus release them from their temporary
grave.

The small animal with which most of us are
familiar, commonly known as the stickleback,

Instinctive Behaviour of Fishes 1 1 1

is another nest-building bony fish. During the
spawning season the male assumes a metallic
green hue, the lower part of his throat being a
bright crimson colour. The fish constructs his
nest in the water it inhabits by collecting a
quantity of grass-stalks, which he cements
together with a layer of mucus exuded from
the surface of his body. In this way a dome-
like hollow structure is reared in the side of
which a hole is left, its edges being strengthened
and rounded off with great care. The fish then
seeks a mate, and conducts her to the nest he
has made; she enters it, and in a few minutes
has laid some eggs. This process is repeated
day by day until the nest contains a consider-
able number, of eggs. The male then takes up
a position for a period of about a month to
defend the nest from invaders. During this time
he has frequently to fight with larger fish than
himself; in making these attacks the little
creature seizes their fins and strikes furiously
at their head and eyes. As the young fish
appear and grow they are apt to stray ; the male
brings them back to their allotted precincts
until such time as they are able to protect them-

ii2 Instinct and Intelligence

selves, when he ceases his guardianship and
returns to freedom.

The action taken by salmon in the prepara-
tion of spawning-beds, and the care of their
young is remarkable; after passing from the
sea the female deposits her eggs in shallow
furrows in the gravel, to which they adhere by
a thin coating of glutinous matter. The
trenches in the sand are made by the female
throwing herself at intervals of a few minutes
upon her side, and while in that position, by a
rapid action of her tail, she digs a receptacle
for her eggs a portion of which she deposits,
and turning on her side she covers them over
with sand. The male seems to take no part in
this work, but after it is completed he acts as
a sentry over the eggs, for which he has at
times to fight fiercely, for other male fish are
anxious to appropriate his charge. He is thus
kept incessantly on the alert until the eggs are
hatched, and the fry able to take care of them-
selves.

Mr. Pennell states that in company with Mr.
Bartlett, Superintendent of the Zoological
Gardens, Regent's Park, he visited the house

Behaviour of Lower Vertebrates 113

in which perch are kept; the keeper of these
fish was also present. So long as the keeper
walked about in front of the aquarium occupied
by the perch they took no notice of him; but
on Mr. Bartlett directing this man to walk away
from the tank towards the cupboard where the
net was kept by which food was introduced into
the tank, the fish became intensely excited the
instant the keeper made this movement and
rushed to and fro across their tank, erecting
their fins and exhibiting unmistakable emotional
movements.

Much more evidence might be adduced to
establish the fact that the instinctive move-
ments made by the animals included in the
three lowest classes of true vertebrates result
from purely instinctive processes, and generally
become manifest in definite traits of character
which we are accustomed to attribute to self-
preservation, parental affection, anger, jealousy,
fear, self-reliance, and sympathy in a low form.
That these traits of character are the outcome of
instinctive processes is evident, in that to a
greater or less extent they are common to all
the orders of animals included in the three

H

ii4 Instinct and Intelligence

lower classes of vertebrates ; that they are
hereditary is shown by the fact that they are
manifested by the young of the same orders of
beings in all parts of the world. That they
depend largely on work performed by the nerve
cells of the mid-brain, including its basal
ganglia or lower nervous centres, is shown by
the fact that after the destruction of this part
of the brain, although an animal may continue to
live, its instinctive powers are abolished. Prof.
Pagano observes, as the result of numerous
experiments on adult and new-born animals,
that after their basal ganglia had been destroyed
their movements of expression distinctly at-
tributable to emotional states were abolished.
He asserts that the physiological preorganised
mechanism of instinctive and emotional re-
actions are to be found at birth and in after-
life in the basal ganglia.1

We may now pass on from the class of fishes
to the Amphibians as represented by frogs and
lizards. It is evident the sensory organs and
brains of many of these animals are of a some-
what higher order than those possessed by car-

1 Archives Italiennes de Biologic, 1906.

Basal Ganglia of Amphibia 115

tilaginous or bony fishes. For instance, the
common bull-frog, in addition to a membranous
labyrinth such as exists in the auditory ap-
paratus of fishes, possesses the rudiments of a
structure known as the cochlea, which plays an
important part in the appreciation by the
animals of differences in sound. From experi-
ments made by Prof. Yerkes, it seems that
frogs appreciate differences in sound, as demon-
strated by their movements, and in an alteration
in the rate of their respiration when exposed to
differences of range of auditory vibrations.
That these movements depend on the action of
the auditory apparatus, and corresponding cere-
bral centres is shown by dividing the auditory
nerves of these animals — that is, by destroying
the connection between their ears and auditory
cerebral centres; after this has been done, the
animal's movements in response to vibrations
of sound are abolished.

Having in part adopted a terrestrial mode
of life, the olfactory organs of Amphibia have
become somewhat modified in response to the
altered nature of their environment; they
afford a direct passage for air to the animal's

H 2

n6 Instinct and Intelligence

lungs, and have developed specialised olfactory
sensory organs. To a large extent, however,
this class of animals has to depend on their
visual apparatus to enable them to gain their
supply of food and to warn them of approach-
ing danger. Their central nervous system has
evidently responded to this demand, foj: it has
become so far developed as to enable the
Amphibia to appreciate between differences in
colour. This is demonstrated by forcing a frog
to follow a certain track in a labyrinth in order
to obtain a supply of food.1 At a point in the
labyrinth where a choice between the right and
wrong paths was necessary " a red card was
placed on one side and a white card on the
other side. When the frog had learned to take
the correct path towards the white, the cards
were exchanged without any other alteration
in the conditions, and the decided confusion of
the animals indicated that they had dis-
criminated between the red and white cards,
and had learnt to react with reference to this
discrimination."1 The small green tree-frog,

1 Journal Comp. Ncur. and Psych., Vol. XV., p. 279.

2 The Animal Mind, by M. F. Washburn, p. 142.

Basal Ganglia of Insects 117

after a hundred trials, learned without a fault to
follow the right path by which to obtain its food
in a simple labyrinth.

Professor Flourens found that after he had
removed the cerebral hemispheres of a frog the
animal continued to swim when thrown into the
water. Movements of this kind are due to
stimuli received by the tactile sensory organs
of the animal's body, which pass to the nerve
cells of the spinal cord and through their motor
fibres to the muscles concerned in the act of
swimming. The neuro-muscular system of
these animals has acquired the power of
executing these movements in virtue of the
hereditary structural arrangement of its ele-
ments, which had been exercised and thus im-
proved during the previous lifetime of the
animal. But, as Professors Goltz and Schrader
have shown, if, together with the cerebral hemi-
spheres, the basal ganglia are destroyed, the
animal loses all power of instinctive reflex
action; a frog thus mutilated will, if left to
itself, remain motionless until in the course of
time it dies. If the cerebrum of a frog is
removed exclusive of its basal ganglia, instinc-

n8 Instinct and Intelligence

tive actions are retained. If an obstacle is
placed in the path of an animal which has been
thus mutilated, and it is then excited by a prick
in its foot, it moves away so as to avoid the
obstacle. The mere act of leaping away may
possibly, in case of necessity, be regarded as a
reflex action; but the fact that the frog avoids
the obstacle shows that its instinctive elements
are still at work, and are located in the nervous
substance of the basal ganglia.1

Reptiles form the lowest class of vertebrates
which lead a wholly terrestrial existence, their
lives depending on the perfection of their
visual, auditory, and tactile sensory organs and
the corresponding cerebral centres. The living
substance of these organs has, among the
" fittest " of this class of beings, responded to
the streams of energy derived from new and
varied external sources. For instance, the eyes
of reptiles have developed structures whereby
they 'focus on their retina waves of light pro-
ceeding from near and distant objects. Their

1 Professor Schrader concludes from the result of his experiments
on frogs, that their central nervous system can be divided into a
series of sections, each of which is capable of performing an
independent function.

Development of Neopallium 119

retina consists of an outgrowth from the brain
which terminates in a cup-like receptacle for
the dioptric apparatus of the eye. In some
reptiles the vestiges of a pair of eyes located
on the upper surface of the animal's skull exist
in addition to their lateral organs of vision.
The auditory sensory organs of many reptiles
possess structures which greatly facilitate the
transmission of waves of sound to the auditory
nerves and brain centres. The nose of reptiles
also consists of an elaborate arrangement of
structures adapted to present an extensive sur-
face for the growth, and development of sensory
organs connected with the olfactory nerves and
cerebral centres.

The flow of energy from the outside world,
and from internal sources passing to the central
nervous system through the sensory organs of
reptiles, has exercised a stimulating effect on
the development of their terminal nerve cells
and pallial structures, which have thus become
more pronounced than those possessed by the
two lower classes of vertebrates.1 The con-

1 The Nervous System of Vertebrates, by Prof. J. B. Johnston,
pp. 257, 314.

I2O Instinct and Intelligence

necting fibres of these centres and of the spinal
cord form a complex arrangement of paths by
which pre-existing mnemic impressions are
brought into harmonious action, and become
manifest in purposive instinctive movements.
For example, Prof. W. H. Wilson has found
that " stimulation of the optic lobes of the large
Egyptian iguana produces movements of
various parts of the body, and that there is a
definite and precise motor localisation in the
mid-brain of these reptiles — a localisation
which is determined by the ending of the tactile
tracts (from the body generally) in this part of
the brain." 1

But as with the two lowest classes of verte-
brates, so also with reptiles, their brains cannot
be said to contain structures to which we can
properly apply the term "neopallium "; the
development of their cortical or pallial elements
has been effected by the flow of energy which
reaches them, but the crowning achievement of
this process, consisting in the development of
a true neopallium, has not been effected by the
reptilian brain. The behaviour of this class of

1 Arris and Gale Lectures, by Prof. Elliot Smith.

Basal Ganglia of Birds 121

animal depends on the nature of the hereditary
instinctive qualities of the nervous matter con-
stituting their basal ganglia and mid-brain.
From experiments made by Prof. Yerkes it
appears that these movements may, in certain
reptiles, become altered if the animal is sub-
jected to appropriate treatment; in other words,
the behaviour of reptiles is capable of being
modified by proper training. Thus turtles,
when subjected to labyrinth training, gradually
learn how to follow rather complicated paths
in order to reach their food. If an inclined
plane is so placed as to intercept their path,
to shorten the journey turtles on reaching the
summit of the obstruction, systematically throw
themselves over its edge so as the more speedily
to reach the food contained in the water of their
feeding tank.1

Among the class of birds the brain is remark-
ably constant in its outward form; its most
characteristic feature is the great size of the
basal ganglia as compared with other parts of
the brain. The increased development of these
structures is the result of the constant use

1 The Animal Mind, by M. F. Washburn, p. 222.

122 Instinct and Intelligence

necessarily made by birds of their visual, audi-
tory, and tactile sensory apparatuses in order
to maintain their existence. The evolution of
the basal nervous system of birds, in response
to the action of their environment, accounts for
the surprising instinctive qualities displayed by
many of this class of animal ; the careful pro-
vision they make for their young, their self-
reliance, jealousy, and other instinctive quali-
ties are so well known that it seems unnecessary
to dilate on this subject. That these qualities
are hereditary, and become manifest without
having been learnt or gained by experience,
is well illustrated in the account Prof. Lloyd
Morgan gives of a young moorhen which he
had hatched in an incubator, and watched from
day to day, almost from hour to hour.1 When
about nine weeks old this bird was swimming
in a pool at the bend of a stream. A puppy
ran down to the stream barking, and made a
feint from the bank towards the young bird. In
a moment the moorhen dived, disappeared
from view, and soon partially reappeared, his
head just peeping above the water beneath the

1 Instinct and Experience, by C. Lloyd Morgan, p. 4.

Instinctive Behaviour of Birds 123

overhanging bank. This was the first time the
bird had dived. Mr. Lloyd Morgan observes
that he had repeatedly endeavoured to elicit
this characteristic piece of behaviour, but had
failed. But now the blundering puppy suc-
ceeded in causing the small bird to execute a
series of complex movements which, on their
first occurrence, were independent of prior ex-
perience, and were directed towards the well-
being of the individual. He adds : " Such
behaviour is, I conceive, a more or less com-
plex organic or biological response to a more
or less complex group of stimuli of external
and internal origin, and it is, as such, wholly
dependent on how the organism, and especially
the nervous system and brain centres, have been
built through heredity under that mode of
racial preparation which we call biological
evolution."

From the basal ganglia of a bird's brain
numerous nerve fibres pass to the superficial
layer of cells forming the pallium of its hemi-
spheres ; the structures entering into the forma-
tion of this layer are more distinctly differen-
tiated and of a higher type than those of the

124 Instinct and Intelligence

corresponding areas of the reptilian brain.1 If
definite spots of a bird's pallium are stimulated
certain groups of muscles of the animal's limbs
and body are brought into action, thus showing
that the energy released from this part of a
bird's brain passes to motor centres, and thence
through the spinal cord to the contractile ele-
ments of the muscle cells.2 After the complete
removal of a bird's cerebrum, although the
animal may continue to live for some time if
fed artificially, it loses all instinctive powers;
it, however, responds to tactile impressions by
reflex action. But, as Prof. Elliot Smith
observes, birds possess such a highly specialised
and diversely modified cerebrum that they
seem to have left the path leading to the forma-
tion of a true neopallium, such as that which
forms a characteristic feature of the Mammalian
brain.

1 The Nervous System of Vertebrates, by J. B. Johnston,
p. 149, Fig. 74.

2 The Evolution and Function of Living Purposive Matter, by
N. C. Macnamara, p. 100.

CHAPTER V

The Neopallium in Mammalia, extinct and surviving —
The Tasmanian Devil — The Duckbill — Release of
energy in response to stimuli — The folds of the
Mammalian brain — The functions of the cortex —
Cortical areas — Intelligence in dogs — Macaques —
Areas of Neopallium — Learning by imitation —
Baboons — Limits of intelligent action.

BEFORE attempting to explain the evolution
and functions performed by that part of the
brain which is directly concerned in the mani-
festation of intellectual processes, it is well to
observe that, as Professor Elliot Smith re-
marks, in each successive epoch it has become
incumbent upon every mammal either, on the
one hand, to adopt some eminently safe mode
of life or some special protective apparatus to
avoid extinction ; or, on the other hand, to " cul-
tivate " a larger cerebral cortex or that part of
it known as the neopallium which, as the organ
of associative memory, would enable it to

125

126 Instinct and Intelligence

acquire the cunning and skill to evade danger
and yet adequately attend to its needs. In
many of the Eocene Mammalia the neopallium
is reduced to such diminutive proportions that
the brain resembles the reptilian type, and in
each successive generation the neopallium be-
comes larger or the creature in self-defence is
compelled to adopt some safe form of life. The
Hippopotamus and the Sirenia are examples of
animals which have not kept pace in the fierce
race for neopallial supremacy, but survive by
adopting habits of life which are eminently safe.
The condition of the human brain represents
the other extreme. Here the neopallium has
attained its maximum development, and its pos-
sessor has not had to seek refuge either in a
retired mode of life, or by protective specialisa-
tion of structure either for offence or defence,
but has attained the dominant position in the
animal kingdom by means of the development
of his intellectual powers, while retaining his
animal or instinctive nature.1

We have noticed (p. 67) that in animals so

1 Cat. of Comp. Anatomy, Vol. II., p. 465, Roy. Coll. Surgeons
of England.

Development of Neopallium 127

low in the zoological series as worms the effect
of exposure of their nervous system to an in-
crease in the complexity of the stimuli acting
on it, has tended to develop the growth and
organisation of its nerve cells. Under like
conditions the cerebral cortex of some bony
fishes is of a higher order than that possessed
by the lamprey ; in reptiles and birds it becomes
differentiated structurally and functionally.
The brain of some of the Marsupialia or pouch
bearing animals structurally consists of some-
thing between that of reptiles and the more
typical mammals. The " Tasmanian Devil "
affords us an example of this order of beings;
it possesses well-developed basal ganglia, into
which nerve fibres extend from the various sen-
sory organs; from the terminal cells of these
ganglia numerous fibres extend to a rudi-
mentary neopallium, from which lines of com-
munication pass to motor cells controlling the
action of the muscles of the animal's body and
limbs. The behaviour of this, one of the lowest
orders of mammals, is evidently governed by
instinct, its fierce nature, strenuous efforts for
self-preservation, and the fondness it shows for

128 Instinct and Intelligence

its young confirm this idea, and agree with the
anatomical structure of its brain.

The snout of the Duckbill is an extremely
sensitive organ ; from it nerve fibres pass to ter-
minal cells located in the basal ganglia; innu-
merable fibres extend from these ganglia to the
nerve cells of the cerebral cortex, and to motor
cells of the lower brain and spinal cord, so that
impressions made on the animal's snout pass to
its instinctive and cortical centres, and by re-
leasing a part of their potential energy cause a
discharge of combined nerve force which, act-
ing on motor cells, become manifest in the pur-
posive and intelligent movements of the
animal's body and limbs. This point may per-
haps be more clearly understood by reference
to the following diagram :—

FIG. 14.

Course of Sensory Stimuli 129

E represents energy derived from tactile
impressions ; a n, the receiving or sensory tactile
organ from which energy passes to b.g., a ter-
minal tactile nucleus located in the basal
ganglia; a part of the instinctive working
energy attached to the living matter forming
the cells of this nucleus being set free, passes
to mn., a motor centre. At the same time some
of the energy set free by the nucleus b.g. ex-
tends to p., a tactile cortical or neopallial centre
setting free a part of its nervous energy which
extends to the motor cells mn. and infuses a
certain amount of nerve force into that derived
directly from the instinctive elements of the
basal ganglia, the result being manifest in the
skill or cunning of the muscular movements
made by the animal which are represented in
the diagram by the letters VA.

The increase in the size of the cerebral cortex
in the ascending orders of mammals seems to
have outgrown that of the unyielding skull by
which it is enclosed, so that its surface layers
have become crumpled up so as to form a num-
ber of infoldings, or sulci, as they are termed ;
on the exterior of the hemispheres the sulci

i

130 Instinct and Intelligence

show as sharply-cut fissures; the intervening
brain-substance is known as forming its con-
volutions. The pattern which the principal
sulci and convolutions of the brain assume in
the various orders of mammals is fairly con-
stant, so that anatomists, by inspecting the sur-
face of a series of brains, is able to state to
which class of animals each of them has be-
longed.

The upper and lateral surfaces of a dog's
brain present several well-defined infoldings of
its cortex ; on the base of the brain a part of its
basal ganglia is conspicuous; they project into
the lateral ventricles or space which exists in
the brains of all the higher orders of animals.
These ganglia, in fact, as in the lower classes
of animals, constitute the receiving central and
dispatching centres for incoming and outgoing
streams of energy, derived from the animal's
nervous sensory organs.

After a dog has been completely anaesthetised
if certain areas of his cerebral cortex are stimu-
lated by an electric current, contractions of
definite groups of muscles of his body and limbs
take place. At one spot excitation of the

Stimulation of Cerebral Centres 131

cortex is followed by movements of the muscles
of the upper limbs ; and so on with other groups
of muscles. These cortical areas are known as
motor centres; like areas on being stimulated
induce similar action in every species of the
canine family. Stimulation of other areas of
a dog's cerebral cortex leads to movements
which, there seems reason to think, depend on
work performed by the cortical nervous matter
governing the animal's feelings or sensations;
but as it is impossible to arrive at any accurate
conclusions regarding a dog's feelings, it is well
to defer this subject until we come to consider
the functions performed by certain areas of the
neopallium of human beings. There are con-
siderable spaces of the cerebral cortex in a
dog's brain situated between its motor and sen-
sory centres, which make no response to any
form of stimuli applied to them. These regions
of the cortex furnish lines of communication
between the various cortical and other nervous
centres, and transmute the energy it receives
into a form which so acts on motor centres as
to impart an intellectual character to the
animal's movements. These so-called associa-

i 2

132 Instinct and Intelligence

tion areas of a dog's brain as compared with
those of a human being are of a rudimentary
type; nevertheless, dogs certainly possess a
certain amount of intelligence or reasoning
power. For instance, Darwin, when referring
to this subject, gives the following details re-
garding the sagacity displayed by a dog
belonging to a Mr. Colquhoun; this gentleman
when out shooting winged two wild ducks,
which fell on the opposite side of a stream. His
retriever tried to bring over both birds at once,
but could not succeed; she then, though never
before known to ruffle a feather, deliberately
killed one of the ducks, brought over the other,
and returned for the dead bird. Colonel
Hutchinson relates that two partridges were
shot at once, one being killed, the other
wounded; the latter ran away, and was caught
by the retriever, who on her return came across
the dead bird ; she stopped, evidently greatly
puzzled, and after one or two trials finding she
could not take it up without permitting the
escape of the winged bird, she considered a
moment, then deliberately murdered it by giv-
ing it a severe crunch, and afterwards brought

Association Areas of the Brain 133

away both birds together. This was the only
known instance of this dog ever having wilfully
injured any game. Darwin adds : " Here we have
reason, though not quite perfect, for the re-
triever might have brought the wounded bird
first, and then returned for the dead one, as in
the case of the two wild ducks."1

Behaviour such as that displayed by these
dogs certainly indicates something more than
mere automatic or instinctive action, and which
is attributable to work accomplished through
means of the living substance of the association
areas of the animal's brain. We rest this belief
on the fact, that if these parts of the brain are
destroyed while the animal's basal ganglia re-
main, such an animal's intelligence and memory
for all it had previously learnt are abolished ;
but its instinctive powers still continue and
become manifest in instinctive behaviour.

It is impossible to draw a hard and fast line
between instinctive and intelligent processes,
the molecular structure of the living substance
constituting the association areas of the neo-

1 The Descent of Man, by Charles Darwin, Vol. I., p. 48,
edition 1871.

134 Instinct and Intelligence

pallium have been evolved from instinctive
elements, raised as it were to a higher level in
response to the increasing complexity of the
environment imposed on the ascending orders
of animals in their struggle for existence.

Although there is much to interest us in fol-
lowing the evolution of the brain of the Ungu-
lates and Cetacea, it does not enlighten us much
as to the connection which exists between the
organisation and growth of the neopallium,
and the development of an animal's intellectual
powers ; we therefore pass on to the order of the
Primates, including the Macaque, whose brain
has been extensively explored by physiologists,
and its neopallium mapped out into well-
defined motor and other centres which closely
correspond with those of the higher orders of
Primates.

The development of the association areas of
a Macaque's brain do not reach the same plane
as those which characterise the brain of the
baboons ; nevertheless, they are of a higher type
than that possessed by a dog ; consequently the
reasoning powers displayed by some monkeys
are more pronounced than those of a lower class

Macaque's Intelligence 135

of beings. Thanks to Mr. Kinnaman we can
form fairly accurate ideas concerning the in-
stinctive and intellectual capacities possessed
by Macaques. He finds that the animals soon
learn to discriminate between different colours,
and also to appreciate the difference between
the size and form of a vessel containing their
food. Mr. Kinnaman had no difficulty in teach-
ing his Macaques to follow the right path
through a labyrinth constructed on the plan of
the Hampton Court maze. He placed food in
a cage which was closed by means of an ela-
borate set of fastenings, which his monkeys had
to open before they could gain admission to the
cage ; the animals soon learnt how to open the
cage, and evinced no small amount of pleasure
when they had successfully completed their
task. The question then arose as to whether a
Macaque could, by watching its companion
perform certain movements, and observing the
consequence be able to accomplish a similar
set of movements from a desire to effect similar
results. The test used consisted of a closed
box containing food ; this box was fastened by
means of a plug; one of the Macaques failed to

136 Instinct and Intelligence

work the mechanism and gave up trying in de-
spair. Its companion, however, came out of her
cage, the first one following her; number two
went to the box, pulled the fastening about and
ultimately seized the end of the plug with her
teeth and pulled it out of its clasp. The box
was again set ; the first animal made a rush for
it, seized the plug as number two had done, and
got her food. She repeated this act several
times.1

In our opinion the behaviour of this family of
apes is attributable to instinctive processes
fertilised, as it were, by nervous energy derived
from the living substance of the association
areas of their cerebral cortex, and therefore
possessing a tinge of intelligence.2

The neopallium of Baboons and Anthropoid
Apes is largely developed in all directions as
compared with that of their lower brethren, and
with this structural development their instincts
and intellectual powers have risen to a higher
standard. For instance, the author was out with
a shooting expedition among the hills near a

1 The Animal Mind, by M. F. Washburn, pp. 238-10.

2 Psychology, "The Study of Behaviour," by W. McDougall,
p. 164.

Behaviour of Baboons 137

place called Colgong, on the River Ganges. Re-
turning home in the evening we saw a troop of
Baboons seated on a ledge of rocks; among
them was a female with a young one close be-
side her. One of our party, without a moment's
thought, fired and killed the young ape; its
body rolled down the rock, and was instantly
followed by the older ape, evidently the young
one's mother. On reaching the dead body she
took it up in her arms, fondled it, and uttered
the most piteous wail, which attracted a crowd
of her companions, several of whom joined her
in her lamentations. The behaviour of these
apes indicated a distinctly high tone of instinc-
tive action; grief, and, as we have stated, sym-
pathy, being innate qualities common to the
same orders of animals under like conditions in
all parts of the world. Thus, on Darwin's
authority, the traveller Brehm, while in Abys-
sinia, encountered a troop of Baboons which at
the time were crossing a valley. Some of them
had already ascended the opposite rocks, and
some were still in the valley ; these latter were
attacked by some dogs and driven away with
the exception of one young animal, who was left

138 Instinct and Intelligence

behind on a ledge of rock and called loudly to
its companions for help. One of the largest
males of the troop came slowly to the young-
ster's aid and led him to a place of safety. Be-
haviour of this kind seems to imply intelli-
gence, the old ape's instinctive action becom-
ing modified by energy discharged from his
visual and auditory neopallial centres by stimuli
derived from cries, and the apparent peril in
which his young companion was placed. Most
of us have witnessed or heard of the surprising
antics which performing apes go through at a
sign or command of their keepers; but it is
doubtful if they utilise acquired habits of this
kind for their own advantage or to promote the
well-being of their fellow-creatures.

CHAPTER VI

The hereditary qualities of the Neopallium and basal
ganglia contrasted — The brain of Tertiary man- —
The brain of a microcephalous idiot — The arrest of
human intelligence when sense organs are absent —
Education through a single sense organ — Associa-
tion nervous centres — The modus operandi of a
sensation — Memory and sensation — Ideas and im-
pressions— The mechanism of reading — Sensory
cortical centres.

WHILE the ordinary movements of invertebrates
and the three lower classes of vertebrates are
regulated by energy derived from their basal
instinctive nervous substance, a part of this
matter has undergone evolution in consequence
of the constant action on it of the new kinds of
energy to which the ascending orders of animals
have been exposed in their struggle for exist-
ence (see Appendix). In this way a part of the
cerebral cortex has become developed into what
is known as a neopallium, consisting of special-

139

140 Instinct and Intelligence

ised layers of nerve cells and fibres possessing
intellectual properties. The nervous substance
and functions of the instinctive or basal elements
of the brain are. strictly hereditary, having a
pedigree extending over long geological periods
and therefore difficult to alter and almost im-
possible to obliterate.1 On the other hand, the
association or neopallial elements of the brain
are, philogenetically, of recent origin; their
hereditary qualities are not so firmly ingrafted
in its substance as those inherent in the instinc-
tive centres; psychical nervous substance is

1 Mr. W. McDougall is of opinion that modifications of instinc-
tive action may be effected, first, by an animal learning to dis-
criminate by experience gained from success or failure of its
instinctive behaviour. Secondly, an animal may learn to react
with one of its instinctive modes of behaviour to an object of a
kind towards which it at first remained indifferent. The third
type of modification of instinctive behaviour consists of a modifica-
tion of the bodily activities that are directed upon the object of
the instinct. He remarks that "when the behaviour of an animal
exhibits modification of a purely instinctive mode of behaviour of
any one of these kinds, we say that it has profited by experi-
ence and behaves intelligently. All animal behaviour is, then,
either purely instinctive or intelligent ; and when we say intelligent,
we mean that it is such as implies some degree of modification
of the innate structure of the mind through experience of success
or failure, pleasure or pain, in the course of purposive activity.
Intelligent behaviour thus always involves modification of instinc-
tive modes of behaviour, and intelligence presupposes instinct, for
unless a creature possessed instinct of some kind, all basis for the
play of intelligence would be lacking, there would be no tendencies
to be modified, and modification of pre-existing tendencies is the
essence of intelligent activity." — (Psychology, "The Study of Be-
haviour," pp. 163, 164.)

Man's Large Neopallium 141

therefore more amenable to training than that
which constitutes the basal ganglia.

Our knowledge of the functions performed
by different areas of the living substance of the
neopallium is based on a study of its structure,
and on experiments made on the brains of apes
and other animals. As regards human beings,
it is derived mainly from the destruction of
definite areas of the brain as the result of
disease or injury. The cerebral cortex, or neo-
pallium, in man consists of five layers of nerve
cells, and a subjacent mass of nerve fibres which
connect together the whole of the complex
structures forming the central nervous system.

The convoluted cerebral cortex of the exist-
ing races of human beings is far more extensive
in proportion to the rest of the brain, and the
surface of their bodies than that of any of the
lower animals. In this respect the nearest
approach to the human brain is that of the
gorilla, which, although much inferior to man's
brain in superficial area, and especially as re-
gards its motor centre of speech, otherwise con-
forms structurally to the type of the human brain.
With a well-developed neopallium these man-

142 Instinct and Intelligence

like apes show a considerable amount of intelli-
gence and capacity for education, although their
behaviour as a whole is markedly governed by
their hereditary instinctive centres. There can
be no doubt that between the type of brain
possessed by apes and human beings there are
missing links, which might possibly have been
filled in to some extent, if we possessed the
skull of a Dryopithecus as well as the animal's
lower jaw.1 One of these missing links is, how-
ever, supplied by the skull, and some of the
bones of an ape-like human being (the Pithe-
canthrop^ls erectus] discovered by Dr. Dubois in
Java in a Tertiary geological stratum. These
bones were found close to one another in the
same geological formation, and were all in a
similar condition of fossilisation, and therefore
in all probability were part of one skeleton. Dr.
Dubois brought these bones to Europe and sub-
mitted them for examination to our leading
anatomists. After much controversy it is now
generally admitted that they are part of an ape-

1 The Dryopithecus of Lartet, which was closely allied to
the anthropomorphous Hylobates, existed in Europe during the
Upper Niocene period ; it was nearly as large as a man. — The
Descent of Man, by C. Darwin, Vol. I., p. 199, First Edition, 1871.

Pithecanthropus erectus 143

like human being who lived in the later Tertiary
period. Dr. Dubois holds the opinion, from
impressions he finds on the inner surface of
this skull, that the brain it once contained pos-
sessed that portion of the cerebral hemispheres
in which Broca's organ of speech is located.
He holds that this area of the brain, in the Ter-
tiary period human being was less than half the
size of the corresponding portion of the brain
of existing Europeans.

This statement suggests the idea that this
being possessed to some degree the power of
articulate language, but from the capacity of
his brain as a whole we feel convinced that his
intellectual powers were of a rudimentary
character, as compared with those of civilised
human beings of the present day.1 We make
this statement on the estimated capacity of the
Java skull, which amounts to 950 c.c. as com-
pared with that of average educated English-
men, who have an average cranial capacity of
1,500 c.c. The capacity of a full-grown male
gorilla's skull is some 600 c.c., the weight of

1 The capacity of the skull is commonly expressed in cubic
centimetres.

144 Instinct and Intelligence

this animal's body being about the same as
that of an average adult human being; this
great difference in the capacity of a human and
a gorilla's skull represents the difference that
exists between the size of their brains.1 (Fig.

15.)

Although it is impossible to ascertain the
exact form of the brain possessed by Tertiary
human beings, the brains of a certain class of
idiots are of such a size and form as would fit
well into the Java skull-cap. We published
some years ago a case of this kind, in order to
show what the probable habits and behaviour
of primitive human beings would have been,
possessing, as we may presume was the case,
brains having about the same superficial area
and configuration as the class of idiots to which
we refer.2

In the case which came under our notice the
individual was four feet eight and a half inches
in height, and broad in proportion to his stature ;

1 Prof. T. H. Huxley, Evidence of Man's Place in Nature,
p. 136. See also The Origin and Character of the British People,
by N. C. Macnamara, p. 28.

2 Journal of Anatomy and Physiology, January, 1903, Vol.
XXXVIII., p. 258. See also Scientific Transactions of the Royal
Dublin Society, Vol. V., Series II.; "The Brain of Microcephalic
Idiots," by Prof. D. J. Cunningham.

FIG. 15. — A, Skull-cap of a Chimpanzee. B, Skull-cap of a
Neanderthaler. C, Skull-cap of the Java skull. D, Skull-cap of
an existing European. E, Skull of a native of Australia. See
The Hunterian Oration for the year 1901, by N. C. Macnamara.

145

146 Instinct and Intelligence

his features were large, coarse, and devoid of
expression. His long arms and small head with
its receding forehead gave him an ape-like
appearance. (Fig. 16.)

This poor lad had never been able to speak,
but expressed such wants, and any ideas he
could formulate by signs and inarticulate
sounds. He attached himself to persons who
were kind to him and followed them about
from place to place. His power of sight, hear-
ing, touch, and taste were all good ; but it was
impossible, notwithstanding the most patient
efforts to teach him to speak or do such work
as that of sweeping out a room. The intellectual
power possessed by this individual was inferior
to that of some of the lower animals. His
habits were dirty, and he was very passionate;
when out of temper he became violent, throw-
ing himself on the ground and uttering loud
inarticulate sounds. His general health was
good until he reached the age of twenty-one,
when he contracted disease of the lungs, from
which he died some twelve months later.

After death it was found that the weight of
this youth's brain was under 20 ounces (the

Idiot's Brain

average weight of adult Englishmen's brains
being from 48 to 50 ounces), and that the part

FIG. 16.

of the frontal lobe in which the "organ of
speech " is located had not been developed, so
that the part of the brain (Island of Reil) which

K 2

148 Instinct and Intelligence

in man is covered by the posterior part of the
third frontal convolution, was, in the case of this
idiot, exposed. It is unnecessary for us to enter
into a further anatomical description of this
brain, which has been elsewhere fully described.
But we may observe, that the form and size of
this idiot's brain differs less from that of the
brain of an anthropoid ape, than it does from
the cerebrum of a normal adult European. We
may go beyond this, and state that the brain of
this individual was more nearly allied struc-
turally to that of an adult male chimpanzee than
to that of an average human cerebrum.1

Our object in drawing attention to the form
and dimensions of the skull and so of the brain
of anthropoid apes, as compared with that of
our human progenitors and existing races of
men, is in order to show that, with about the
same weight of body their intellectual capacities
have advanced in proportion to the increase in
the size of their cerebral hemispheres; for it is
owing to the growth of this part of their brain
that its bulk has advanced from that of a chim-
panzee of 600 to 1,500 c.c. This increase of

1 Human Speech, by N. C. Macnamara, pp. 226-7.

Intellectual Processes 149

man's neopallium has probably resulted to a
considerable extent from the development of
his motor cerebral area of speech, and the power
he has thus gained of expressing his thoughts in
intelligent language. If, as in the case of the
idiot we have referred to, the motor area of the
brain regulating the action of the muscles of
articulation has not been developed, and the
cerebral hemispheres as a whole are imperfect,
the intellectual powers of such an individual
are of a low order, and he is unable to express
his thoughts in articulate language. The size
of the brain, however, is by no means the only
thing which determines the standard of an
individual's intellectual powers; its inherited
qualities, state of nourishment, and the training
its nervous substance has undergone in early
childhood are factors which influence the kind of
work it is able to perform. To appreciate this
fact at its true value we must endeavour to
understand the nature of the mechanism, the
orderly working of which is the essential
requisite for the occurrence of intellectual pro-
cesses.1

1 The Brain in Health and Disease, by Dr. J. Shaw Bolton,
pp. 51-123.

150 Instinct and Intelligence

On referring to Fig. 17 it will be seen that
considerable intervals exist between the sensory
and motor cortical centres; in the brains of
ordinary human beings these spaces are occu-
pied by nerve fibres and cells which constitute

Broca's Convolution
or senso- motor
speech Cfnlrt.

FIG. 17. — Diagram of left cerebral hemisphere (outer surface) of

human brain. (From Halliburton 's Handbook of Physiology,

p. 688.)

its psychical or association areas. It is in these
parts of the cerebrum that energy passing from
sensory to motor cortical centres is transmuted
into intellectual processes, and in that form
stimulates the motor centres which control

Association Areas of Brain 151

the action of the muscles of our bodies and
limbs.

In order to comprehend the working of this
system, it is well in the first place to remember
the part taken by the sensory organs of our
bodies as receptors, and modifiers of energy
derived from external and internal sources, by
which energy the system we have above referred
to is ordinarily kept in action. To illustrate this
point we can hardly do better than study the
effects produced on the normal development of
a child's intellectual powers when, in his early
life, the principal portals by which energy
passes to his brain are destroyed.

Laura Bridgeman was a healthy infant, and
grew in body and in intelligence until she had
reached her second year of age, when she was
attacked by fever which completely destroyed
her eyesight and her power of hearing. Laura's
mother, in spite of all her efforts, was unable
to teach her child to speak or to notice any
sound. Laura Bridgeman, in fact, from her
second until between her seventh and eighth
year of age was dumb as well as deaf and blind.
Dr. Howe states, -that until Laura was over

152 Instinct and Intelligence

seven years of age she "occupied a place in
her home no higher than that of an intelligent
animal upon whose instruction much labour
had been bestowed." Her intellectual capacity,
so far as an opinion could be formed, remained
undeveloped ; her sense of touch, however, was
unimpaired, and she was thus able by the use
of her hands to feel her way about the house
in which she lived. Before entering the institu-
tion for the blind, which she did when seven
years of age, L. Bridgeman had been taught by
means of her sense of touch — that is, through
moving the tips of her fingers over raised
letters — to recognise words which were attached
to a number of articles in common use, such as
knives, forks, spoons, and so on. She had,
however, no conception of anything beyond
this mechanical form of knowledge, the result
of which, Dr. Howe observes, " was about as
great as if one had taught a number of tricks
to a clever dog." After long and patient
teaching, so as to exercise her sense of touch as
highly as possible, Dr. Howe states, Laura B.
seemed to have gained ideas that the symbols
she was employing meant definite things.

Sensory Organs and Intelligence 153

" Immediately she realised this her counte-
nance beamed with human reason ; she could no
longer be compared to a parrot or a dog."

Another remarkable case of a similar kind to
the above is reported by Mr. E. Chamberlain,
and subsequently by H. Keller herself.1

H. Keller when she was nineteen months
old was seized with a fever, through the effects
of which she completely lost her sight and
hearing. Her other special senses were un-
impaired. From the time, of this illness until
she reached the age of seven years, H. Keller
states that her life was a blank, meaningless,
and concerning the events which took place
before she reached the age when her regular
education commenced she remembers little or
nothing; she lived during this period, as she
expresses it, in a condition of mental fog.
Those who knew H. Keller during these years
state that the predominant features in her char-
acter were her excitable, passionate nature and
love of mischief. When she was rather over
seven years of age she came under the influence
of a wise and experienced teacher, and under

1 The Story of the Life of Helen Keller, by H. Keller, 1903.

154 Instinct and Intelligence

her instruction she passed through a preliminary
course similar to that followed by Laura
Bridgeman. As her sense of touch became
more delicate, her tutor, by signs made with her
fingers in the palms of her pupil's hands spelt
the names of things in common use. Referring,
however, to this period of her life, H. Keller
remarks that " in the still, dark world in which
I lived there was no sentiment, no tenderness."
The signs made and received were, as in the
case of Laura Bridgeman, mechanical, the out-
come of work done by the living matter of her
basal ganglia; the hemispheres of her brain
were as yet hardly brought into play through
the cerebral centres of touch. This condition
of things continued for a considerable time.
One day, however, H. Keller and her tutor
came to a stream of water, into which the latter
placed her pupil's hands, and while there traced
on the palms of them the letters w-a-t-e-r.
H. Keller states: "My whole attention being
fixed upon the motion of the water and the
motion of my instructor's fingers, I recognised
a connection between the two, and that water
meant something that was flowing over my

Sensory Organs and Intelligence 155

hands, the thing had a name." From this
beginning H. Keller's knowledge of things
rapidly increased, and in the course of time she
acquired the power of lip-reading and of
articulation.1

From the history of these individuals we
learn, that from their second to their eighth
year of age they were unable to name things
either in silent or articulate language. Their
power of memory or of forming ideas was
rudimentary. H. Keller states that for six
years before her education commenced her
intellectual faculties were in a condition which
she likens to that of a dense fog. We conclude
that after these children had lost their sight
and hearing, and consequently their power to
receive impressions and gain ideas regarding
external objects through their eyes and ears,
their intellectual powers had ceased to develop.
We say ceased to develop, because until they
lost their sight and hearing they were as intel-
ligent as most other children of the same age.

1 From The Story of the Life of II. Keller, written by herself,
we learn much that is most interesting regarding her mental
development, which attained to so high a standard as to enable
her to gain a university degree.

156 Instinct and Intelligence

Taking this fact, and also that of their subse-
quent histories into consideration, we conclude
that the brains of these beings possessed the
mechanism by which they might have expressed
their thoughts in intelligent speech, but that the
machine failed to work. Their sensory, motor,
auditory, visual, and tactile centres were, in
conjunction with the association areas of their
cerebral hemispheres, capable of performing
their ordinary functions, but the two former
important receptors of energy had been de-
stroyed, so that the sensations and ideas which
children usually acquire through these sense-
organs were not formed; the consequence was
that the functions of the association areas of
these children's brains remained undeveloped,
until they had been brought into action by the
skilful training of their tactile sense-organs, and
corresponding sensori-motor nervous centres.
This training consisted in the persevering
exercise of the nervous matter forming the
tactile sense-organs of their fingers, and thus
in bringing their corresponding sensori-motor
cerebral centres into a high state of physio-
logical perfection. By a process of this kind

Sensory Organs and Intelligence 157

the dormant intellectual powers of these
children were brought into play, and they
gradually came to comprehend that external
things could be specified by definite symbols
or movements made with their fingers, i.e., that
it was possible to express their thoughts in
manual signs.

It was the exercise of their sense organs of
touch, and the motion of their fingers which
brought the inherent power of their association
nervous centres into healthy action.

Passing from the eyes, ears, and the other
sensory organs of our bodies, ingoing or
afferent fibres may be traced which extend to,
and terminate in relation with aggregations of
nerve cells known as the sensory cortical
centres, located in definite areas of the cerebral
hemispheres ; in their passage to these centres
the fibres give off branches to the basal ganglia.
(See Fig. 14.) The nerve cells forming the
sensory centres are brought into relation with
motor cortical centres by means of association
fibres. From the motor centres fibres extend to
the lower brain and spinal cord, and in their
passage give off branches to the nuclei of nerves

158 Instinct and Intelligence

terminating in effective muscular and other
organs, by which energy is distributed to the
contractile elements of muscles, and to gland
cells.

Energy derived from any object, such for
instance as a rose, passing to our retina releases
a part of the energy attached to its nervous
elements; the energy thus set free extends
along fibres to corresponding sensory cortical
centres, and is followed by a visual sensation
or feeling; at the same time the incoming
stream of energy makes an impression on some
of the mnemic elements of the sensory centre,
in the form of a visual image of the colour and
form of the flower.

The visual, auditory, tactile, and other cor-
tical centres, however, are constituent parts of
the cerebral hemispheres which possess psychical
functions. When the potential energy of a
sensory centre is liberated by the re-excitation
of its charged or impressed elements, part of
its energy is liberated and sets free from sur-
rounding association centres a certain amount
of nerve force which gives reality to the sensa-
tion, that is to an idea of the form and colour

Psychical Processes 159

of the rose. There is reason to believe that a
sensation is a purely automatic process; it is
only when the potential energy attached to its
nervous elements in the form of an impression
is released by a fresh stimulus of its mnemic
elements, and passes to surrounding association
nervous matter that an idea or intelligent image
of the constituent parts of the object which has
caused the impression becomes a reality.

For instance, when we first saw a rose we
may have smelt it and have plucked it from
its stem. In this way, at the same time as our
visual mnemic elements received an impression
of the form and colour of the flower, our olfac-
tory and tactile sensory centres also became
impressed by its odour and feel. Energy dis-
charged from any one of these charged centres
releases energy from the other centres, and
leads to a real and complete idea of the rose.
The sensation imparted by a rose that we have
once seen is not totally lost after the flower has
disappeared, for if we again see a similar flower
we recognise it as one we have seen.

Take another example. We see a friend and
greet him. In this case the form of our friend

160 Instinct and Intelligence

produces a visual sensation and impression;
the salutation is the result of its action on motor
centres -plus an intercurrent stream of released
psychical nervous force. (See Fig. 14.) It is
evident the sensation produced by the external
stimulus is not alone a sufficient cause for the
salutation, because if in place of a friend we
had met someone we disliked we should not
have saluted him. It is plain that a latent
image of our friend had been re-excited when
we met him; a psychical image stored in our
brain had been brought into action, and the
contents of the idea thus produced has assumed
an intelligent form in the association areas of
our cerebral cortex, and, guided by the result
of experience, is followed by the contraction
of definite groups of muscles.1

An idea, therefore, means the thing or
movement which has produced the sensation,
and the contents of the idea consist of energy
derived from the characteristic features pos-
sessed by the object or movement which has
caused the sensation. Latent impressions thus

1 Introduction to the Study of Physiological Psychology, by
Prof. Theodor Ziehen, pp. 20, 285.

The Contents of Ideas 161

formed remains dormant until the elements
upon which they have been established are re-
excited, when their potential energy being set
free, is transmuted into nerve force and be-
comes manifest in a real image of the object
or of the movement which has caused the im-
pression. In order, therefore, that an idea
should assume the form of a real image of the
object or movement which has caused the
sensation, the elements on which the principal
features of the object have been established
must be re-stimulated by a similar or kindred
form of energy to that which produced the sen-
sation. Prof. Ziehen illustrates this point by
comparing the living matter of the impressed
nervous centres to the wheels, stars, etc., formed
out of gas-pipes as we see them in illumina-
tions. Unlit, they resemble the so-called latent
ideas; the charged materials are there, but a
spark must first light the gas that escapes from
many holes of the pipe in order that the latent
form may become a reality.

The act of reading aloud illustrates our
meaning as regards the association of ideas in
operation. Energy derived from the concen-

L

1 62 Instinct and Intelligence

tration of our eyes on printed words passes to
our visual and auditory word centres; a part
of their mnemic energy is thus released and
excites neighbouring association nervous ele-
ments, followed by the discharge of nerve force
which by practice travels along association
fibres offering the least resistance to psycho-
motor centres, and leads to the utterance of
word sounds corresponding to those from which
the original visual impression was derived.1
The efficient working of a system of this kind
is gained by its exercise ; any fault in the
sensory organs or in the nervous apparatus
hinders its perfection, but under favourable
conditions the more regular the exercise of the
materials involved the more readily do they
respond to the energy acting on them ; physio-
logical and pathological science corroborates
this statement. It has been proved that after
the excision of the association nervous sub-
stance surrounding a dog's visual centres, or
the destruction of the corresponding part of
the cortex by disease in human beings, the dog

1 Halliburton 's Plandbook of Physiology (eleventh edition), p.
741 ; also A Text-book of Physiology, by Landois and Stirling,
Vol. II., pp. 962, 988, 996.

Psychical Nerve Force 163

or the individual becomes mentally blind; that
is, he can still see, as appears from his fol-
lowing objects moved in front of his eyes
and avoiding obstacles placed in his path,
but he no longer recognises what he sees.
The dog no longer crouches when threatened
with a whip or attempts to avoid a stone thrown
at him ; the man stares at the most familiar
objects as if they were wholly unknown to him,
and recognises them only when he touches
them. Again, the auditory sensory cortical
centres are located in well-defined areas of the
cerebral hemispheres (Fig. 17). The func-
tions performed by a part of their living sub-
stance is to retain the impression made on them
by word sounds spoken by another person ; this
part is recognised as constituting our auditory
word centres. When these charged centres are
re-excited, part of their energy is released, and
extends to the motor centres which order the
action of muscles controlling the vocal ap-
paratus. If, however, these auditory word
centres are destroyed by disease, the latent
word sounds established upon them perish and
cannot be replaced, and a person affected in

164 Instinct and Intelligence

this way is therefore dumb, not because he is
unable to articulate, but because he has no
words at his command ; he may still be able
to see, feel, and smell, and, as far as possible
without the help of words, think and reason.1

Dr. J. Shaw Bolton gives an excellent
account, in the eighth chapter of his book on
" The Brain in Health and Disease," as to the
probable mechanism of the cerebral association
processes which, in human beings, result in the
elaboration of articular language and thought.
The employment of words as articulate symbols
to express the contents of impressions made on
cortical sensori-motor centres must release a
form of energy peculiar to human beings
which probably tends to aid in the evolution of
the psychical elements of their brains.

1 The Evolution and Functions of Living Purposive Matter, by
N. C. Macnamara, p. 140.

CHAPTER VII

The cerebral cortex and insanity — The inherited instinc-
tive powers of the new-born — Development of
cerebral hemispheres and formation of conceptions
of space, etc., due to stimulation from without —
The nervous element in reflex action — Acquired
reflexes — Their seat in the Neopallium — Develop-
ment of this and basal ganglia the physical basis
of education — Hereditary development of basal
ganglia cells — Emotional expression in children
born blind and deaf — Heredity in an Andaman
tracker — Hereditary qualities capable of being
modified — Training of animals — Iristinctive qualities
to be cultivated or repressed — Instinct usually more
to be relied on than intellect — Early training essen-
tial— Free play to children's actions advocated —
Training of association areas of the brain — The
Montessori system — Misdirected education of to-day
— Aim of education — Classification of pupils —
Cadet courses with technical training.

WE have shown that energy, after passing
through sensory organs exerts a powerful influ-
ence on the development of those parts of the
brain whose function it is to associate the con-
tents of ideas and to transmute them into intel-

165

1 66 Instinct and Intelligence

lectual processes. The following pages will
further show, that the neopallium also consti-
tutes the organ by which the movements of the
higher orders of animals become speedily ad-
justed to changes of their environment. In
conclusion, we indicate the lines on which the
results of a study of the nature and functions
of the brain may be applied in forming sound
ideas as to the education of children.

It is found that the nerve cells of the neo-
pallium of imbeciles are structurally defective
when compared with those of right-minded
people; in fact, in proportion to the deficiency
of the cerebral cortex in this respect so is the
intellectual deficiency.1 One of the earliest
symptoms of a disease known as the general
paralysis of the insane, which depends on the
degeneration of the nerve cells and fibres of
the cerebral cortex, is a peculiar hesitation and
irregular movement of the lips and other
muscles concerned in the production of articu-
late speech, which indicates an impaired action
of the terminal nerve cells constituting the

1 The Brain in Health and Disease, by Dr. J. Shaw Bolton,
PP- 37» 86.

Neopallium and Intelligence 167

sensori-motor cortical centres of speech. At
the same time an individual suffering from this
disease unconsciously drops syllables in the
attempt to form spoken sentences or in writing.
In like manner, when trying to think he finds
that his memory for certain words is defective,
so that even in the early stages of general
paralysis a person may be incapable of manag-
ing his own affairs. We thus have proof that
there is a corresponding loss of the individual's
intellectual powers in persons born with a de-
fectively developed neopallium, or in those
whose nerve cells and fibres, of this part of the
brain, degenerate.1

If we turn to the other side of the picture
we find that the intellectual capacity of a
healthy child is in proportion to the perfection
of the structural development of the nerve cells
and fibres of his cerebral cortex.

Those of us who, as medical practitioners,
have had an opportunity of watching the move-
ments of a new-born infant, can have arrived at
no other conclusion than that a child imme-
diately after birth possesses inherited instinc-

1 The Brain in Health and Disease, by Dr. J. Shaw Bolton,
P- 37$-

1 68 Instinct and Intelligence

tive and emotional powers ; for if the infant is
brought within reach of his mother's breast he
seizes the nipple, directs it to his mouth, and
begins to suck; if thwarted in this action the
child gives vent to his emotional feelings by
crying. (See foot-note, p. 185.) When a lighted
candle is brought near an infant's face it acts
as a stimulus to his visual nervous centres, and
leads to reflex contractions of groups of
muscles as shown by his outstretched arms to-
wards the flame regardless of the consequences ;
a young infant fails to make any reasonable at-
tempt to remove anything which may be causing
him pain.1 The reason for this is, that the ner-
vous structures entering into the formation of
an infant's spinal and basal system are more
fully developed (myelinated), at the time of his
birth than his cortical cerebral substances; so
that reflex and automatic instinctive movements
are then possible through the base and stem of
the brain, while at this early age the structures
forming the association areas of the child's
cerebrum are immature, and consequently his
intellectual powers are defective.

1 The Dawn of Character, by E. R. Mumford, pp. 27, 29, 43.
See also p. 21.

Psychical Processes 169

A healthy infant will lie for hours moving his
limbs about in an aimless manner. These
movements, however, tend to promote the
growth, not only of the child's bones and
muscles, but also of the nervous substance of
his cerebral hemispheres, because the constant
movements bring numerous muscular sense-
organs into action, thus leading to a discharge
of energy which passes to sensori-motor centres,
and by exercising their elements promotes their
organisation and also that of the cerebral cortex
as a whole. That this is the case is shown by
the fact, that an infant four or five months
old not infrequently ceases crying to be fed
when he hears his nurse's voice, showing that
he has come to associate the sound of her voice
with the relief of the cause of his distress.1

Infants when about six months old, as a rule,
make persistent but ill-directed efforts with
their arms and hands to reach any near object,
especially if it happens to be of a bright colour ;
movements such as these depend to a large ex-
tent on reflex automatic action. When a child
is a little older he guides his hands so as to seize

1 Instinct and Experience, by C. Lloyd Morgan, pp. 20, 33.

170 Instinct and Intelligence

a near object; no sooner, however, does he
grasp it than the muscles of his hands and arms
contract, and the object is carried to his mouth.
Action of this description depends on the
stimulation of the tactile sense-organs of the
child's fingers and hands when grasping the
object. At first the combined action of both
visual and tactile impressions is necessary to
effect these movements ; but when a system of
this kind has been constantly exercised, it is
only necessary that the tactile sense-organs
should be stimulated to bring the muscles of the
child's hands and arms into co-ordinated action,
the movement has become a habit. The child
is henceforward occupied in attempting to exe-
cute new movements, which lay the foundation
for processes of selection or choice, and ideas
of the greater and the less.1 The young child
as yet cannot distinguish the difference between
his woolly ball and his wooden bricks, but he
comes by experience to contrast the sensations
derived from soft and hard things ; he stretches
out his hands, but there is nothing to feel or

1 Physiological Psychology, by Prof. Ziehen (Third Edition),
PP. 58, 273.

Origin of " Ego Ideas" 171

which he can pull towards himself; repeated
movements such as these lead to the adaptation
of the nervous substance of tactile and other
centres to impressions made on them through
the sense organs; in this way a child begins to
appreciate distance and space, and to recognise
the fact that his body is something apart from
the rest of the world. These rudimentary con-
ceptions of his own being, or " Ego ideas," by
a child develop rapidly, especially during that
period of his existence when he is passing from
crawling to walking in the erect position. This
fact is confirmed by microscopic examination of
sections of the brain at this period of child-life ;
the nerve cells and fibres of its cortical sub-
stance will then be seen to be more completely
developed than they are at an earlier period of
life.1 We conclude that a child's intellectual
powers come into effective operation simul-
taneously with the development of the struc-

1 Halliburton 's Handbook of Physiology (Tenth Edition), p. 734.
See Quain's Anatomy, p. 178. "A man can think of those things
only of which he has learned to think ; and this learning to think
of an object is a process of gradual building up of that capacity
by successive efforts to think of the object more adequately ; and
that which endures between the successive acts of thinking of this
object is a potentiality (disposition) of thinking of it again." —
Psvchology the Study of Behaviour, by William McDougall,
p. 81.

172 Instinct and Intelligence

tures which form his cerebral cortex; and that
the effective working of his brain, like that of
other organs of his body, depends on the struc-
tural arrangement of the elements which form
its underlying basic substance ; while any im-
provement of its functions implies a similar
improvement in the structures which minister to
their performance. Sensations derived from
the outer world or else from internal sources
form the material from which intellectual pro-
cesses are derived ; as Aristotle long ago stated,
" Nihil in intellectu quod non fuerit prius in
sensu " ; we know, and learn from what we see,
feel, hear, taste, and smell.1

We may now pass on to consider the evidence
on which we base the opinion that, in addition
to the above stated functions, specialised areas
of the neopallium control the movements of
animals so as speedily to adapt them to their
environment.2

Nervous action is reflex; that is, it depends
on the effect produced by energy applied to a

1 See The Nineteenth Century and After, " A Physiological Basis
of Education," by N. C. Macnamara.

2 A " Lecture on the Investigation of the Higher Nervous
Functions," by Prof. T. Pawlow, Brit. Med. Journ., p. 973,
October, 1913.

Conditional Reflexes 173

system of living matter. This system consists
of a sensory organ from which ingoing
(efferent) nerve fibres pass to end in a central
nerve cell; from this cell (afferent) outgoing
fibres extend to effective organs such as muscle
fibres and secreting cells. Stimuli derived from
sensory organs travel to a central cell, and thus
release a part of its potential energy, which is
conducted along afferent nerve fibres to an
effective organ. For instance, a particle of dust
falls into our eye, it acts as a local source of
irritation, and thus excites corresponding cen-
tral nerve cells, from which energy is dis-
charged which, passing to the muscles of the
eyelids and to its lachrymal gland, sets up
spasm of the lids and a flow of tears.

Professor Pawlow, of Petrograd, has for
many years been engaged in studying what he
terms acquired or " conditional " reflexes ; while
movements of the lower classes of animals are
controlled by innate, simple, or " uncondi-
tional " reflexes ; under the influence of evolu-
tion and the adaptability of living matter to its
surroundings, the higher orders of beings have
acquired the power of forming new reflexes by

174 Instinct and Intelligence

which they become adapted to the ever-
increasing complexity of their environment,
new relations being thus established under
new conditions to the advantage of the
organism.

As an example of a simple reflex action we
may refer to the increased flow of saliva which
accompanies the stimulus of food taken into an
animal's mouth; there is no difficulty in col-
lecting the saliva which ordinarily finds its way
into the mouth, so that the quantity of fluid
secreted by the salivary glands can be measured
under varying conditions. While a dog is
eating his food there is, by reflex action, an
increased flow of his saliva. While this is
taking place we may proceed to pinch or other-
wise stimulate the skin of a definite part of the
dog's body. If, when the dog has finished
eating and the increased flow of saliva ceases,
we then irritate the previously stimulated skin,
a fresh flow of saliva takes place, produced
this time by a tactile impression made on
sensory organs of the skin, in place of one
caused by the contact of food with the mucous
membrane of the mouth. Again if, while a dog

Conditional Reflexes 175

is being fed and his salivary glands thus stimu-
lated, we prick or otherwise painfully stimulate
the animal's skin, he naturally shrinks from
our treatment; after a time, when the dog has
ceased eating, if we again apply a painful
stimulus to his skin he no longer shrinks from
it, but there is a marked increase in the
secretion poured out from his salivary
glands.

From these and many other like experiments
it seems clear, that a nervous impulse resulting
from a stimulus which naturally passes to cor-
responding central nerve cells may, under new
conditions, be diverted to another centre — that
is, it is easy by changing the conditions to
divert an impulse from one to another path.
It can be shown that processes of this kind
depend on the action of the living substance of
certain areas of the neopallium ; for if these
parts of the brain are removed during life, no
new or conditional reflexes can be established,
but if at the same time the basal and spinal
systems have been preserved, the animal
responds to stimuli by simple, or it may be
automatic, reflexes.

176 Instinct and Intelligence

Professor Pawlow has also shown that certain
areas of the neopallium form a " fundamental
mechanism," whereby new reflexes are ana-
lysed. Such analysers are, he believes, inces-
santly at work controlling the reactions of
living beings to their ever-changing environ-
ment. He finds that if the anterior half of the
cerebrum is removed all the conditional reflexes
which may have been previously established
are obliterated; the animal appears to have
lost all its normal relations with the outer
world; from a psychological point of view
such an animal is a perfect idiot. After
work on these lines extending over a quar-
ter of a century Professor Pawlow has
arrived at the conclusion that, "the cerebrum
is the organ for the analysis of sensations
and for the construction of new reflexes and
new movements." l

If the evidence referred to in this and the
preceding chapters is trustworthy, and the hypo-

1 Dr J. B. Johnston, in his exhaustive work on the Nervous
System of Vertebrates, p. 292, remarks that the evolution of the
cerebral hemispheres is associated with the mode of life of the
animal ; and the greater its size and internal complexity, so in
proportion is the perfection of the organism's adjustment to its
environment.

The Education of Children 177

theses founded on it reasonable, it follows that
any effort made to develop the moral and intel-
lectual capacities of young people should be
directed towards the efficient training, and nur-
ture of the nervous substance upon which the
manifestation of these faculties depend; to be
more precise, our efforts should be directed
towards developing the nervous instinctive
basic substance of the basal ganglia, and of the
association areas of the neopallium.

The development of a child's character may
be conveniently considered, firstly, with refer-
ence to the training of his hereditary instinctive
qualities, which depend on work performed by
the nervous substance of his lower or spinal
system, including the basal ganglia (see Chap.
IV.); secondly, with reference to the develop-
ment of his intellectual powers, the result we
conceive of work performed by the higher or
association areas of his cerebral hemispheres
(Chaps. V. and VI.). It is, however, to be borne
in mind that when we refer to higher and lower
centres, these, together with all the other parts
of the central nervous system constitute a
single organ which in health work in unison.

178 Instinct and Intelligence

If from one part of this system energy is set
free, an equivalent amount replaces it from
some other part by a process of irradiation or
overflow, by means of which the system is
maintained in a state of equipartition of
energy.

We cannot obtain the same kind of evidence
regarding the functions performed by the
human basal ganglia as that procurable in the
lower animals, (see p. 133) but the clinical
evidence we possess on this subject tends to
confirm the idea, that specific forms of energy
on arriving at this part of the brain are trans-
muted into instinctive and emotional action,
and that this form of matter is passed on from
one to succeeding generations of beings through
the medium of germ cells. This fact is illus-
trated by the histories of the blind and deaf
children we have referred to, whose psychical
capacities remained dormant from infancy until
they had reached their tenth or eleventh years
of age; their hereditary dispositions during
this period of their lives dominated their be-
haviour, and led to frequent outbursts of uncon-
trolled passion, at other times to fits of meaning-

Heredity and Instincts 179

less laughter. Having been blind and deaf
from infancy, these children could not have
learnt from seeing or hearing other people how
to give expression to their feelings by muscular
movements of the kind referred to ; it is evident
their behaviour was the result of inherited
qualities brought into action probably by
stimuli derived from their tactile sensory
organs.

As an example of the inheritance of heredi-
tary instinctive qualities we may refer to an
account in the Westminster Review (December,
1900) of an Andamanese lad who, in the year
1872, came under our observation. The primi-
tive inhabitants of the Andaman Islands, in
order to find their way about the dense jungles
they inhabited, were in the habit of forming a
trail marking certain trees, and carefully noting
irregularities and objects on the paths they tra-
versed. Their power of observation was thus
cultivated, and in the course of many genera-
tions had become extremely keen. An Anda-
manese infant, having been deserted by his
parents, was reared on the premises of the
Chaplain residing at the central station of the

M 2

180 Instinct and Intelligence

Andaman Islands. When this lad was ten
years old he was brought to Calcutta; the day
after his arrival, while walking with him and
his master over the open plain (maidan), we
were suddenly enveloped in one of the dense
fogs common to Calcutta; our party halted,
and were discussing the advisability of remain-
ing where we were until the fog cleared; the
Andamanese lad, hearing what we were dis-
cussing, said he thought he could show us the
way home along the path we had traversed.
He pointed to a stone a few feet from us and
said we had passed it, and a little further on a
clump of grass; and so, like a dog on scent,
he followed on until we came to the public road
which led to our house. The lad said he had
paid no particular attention to the various
objects he recognised on the ground, but that
he must have seen them and had no difficulty
in recognising them again. It seemed to us
that this boy had inherited a sense of observa-
tion similar to that possessed by his progenitors

—a development, in fact, of the instinctive
power possessed by many of the lower animals

—which had remained dormant in his case, until

Instinctive Behaviour 181

surrounding conditions brought these faculties
into play.

The instinctive powers displayed by this lad,
in conjunction with the previous histories of
the deaf and dumb children, strengthens the
idea we have advocated, that the brain of human
beings contains a nervous mechanism possess-
ing innate qualities which, when stimulated by
appropriate energy, become manifest in instinc-
tive action. The evolution of this mechanism
can be traced upwards through the ascending
classes of animals, and constitutes a prominent
feature of the human brain. We thus come to
realise the fact that the animal side of man's
nature results from a specific arrangement of
elements entering into the formation of his
central nervous system which he has inherited
from his. progenitors, and cannot therefore get
rid of or permanently alter. Nevertheless, it
seems possible to modify the kind of work
which the nervous substance of the basal
ganglia performs by educating or influencing
its action through means of the sensory organs,
and still more directly, by energy derived from
association areas of the brain. We know that

1 82 Instinct and Intelligence

the instinctive behaviour of many animals
under the influence of selective breeding and
domestication becomes greatly modified, and
that even wild beasts, if taken in hand when
young, may by the exercise of patient and
kindly treatment have their inherited disposi-
tions much altered, although their savage
natures can never be altogether abolished.
Probably no one ever had a larger experience
as to what can be done in training wild animals
than Carl Hagenbeck, who, when referring to
this subject, observes that all carnivorous
animals " when they are caught young and are
properly treated are capable of being brought
up as domestic pets"; he adds that among
animals, as among men, good and bad are
mixed, and that while the good will develop
itself, the bad can be suppressed.1 With regard

1 Beasts and Man, an abridged translation, by H. S. R. Elliot,
of Carl Hagenbeck 's experience of half a century among wild
animals. Like human beings, animals differ much in their
capacities to be influenced by training. Thus Mr. Bartlett informs
us that having some monkeys for sale, a trainer came to him to
offer a certain price for the lot ; but he said : " If you will permit
me to have them for a week or ten days, I will keep two or three
of the animals and send you back the remainder, for it is only
those who are attentive that T can train ; the inattentive animals
whose eyes are constantly watching a fly or anything moving
about the room are of no use to me ; no amount of teaching will
induce them to learn the tricks I require them to perform."

The Training of Instincts 183

to domestic animals, believing as we do that
our instincts and emotional expressions have
been derived from animal progenitors, it seems
reasonable to suppose that the method employed
by many generations of sportsmen to train
pointers, for instance, might give us an idea of
the kind of treatment likely to succeed in
developing the living nervous matter of our
basal centres. In the year A.D. 1621 a well-
known sportsman, Gervase Markham, observes
regarding the training of pointers that no one
should attempt to take this business in hand
unless he has a real pleasure in the work, and
a natural liking for dogs. He writes as follows :
" You shall beginne to handle and instruct your
dogge at four months old; if deferred longer
it will make the labour greater; make him most
loving and familiar with you, taking a delight
in your company, also mix with this familiarity
a kindly awe and obedience which you shall
procure rather by tenderness than by terrefieing
him, which only maketh him sly. When you
have got thus far in his training you may begin
to teach him the work you desire him to per-
form." Markham is quite clear in his instruc-

184. Instinct and Intelligence

tions regarding the necessity for patience on
the part of a trainer; he observes that it is
wrong "ever to hurry your young dogge,
give him time to fix himself and much
liberty of movement, handle him firmly but
tenderly." 1

It would be difficult to lay down in general
terms principles better adapted for the training
of a young child's instinctive powers than those
given by Markham for the training of pointers.
In other words, a system of education pursued
on these lines is calculated to develop and im-
prove the working of the nervous substance on
which the individual's character depends.2

If commenced in early childhood it is pos-
sible by careful training habitually to curb the
instinctive and emotional activities displayed
by young people. But teachers who have had
large experience in educating children, and who
have lived sufficiently long to see their pupils
grow up to middle age, assure us that children
whose character they had fondly hoped to have

1 The Pointer and his Predecessors, by W. Arkwright, p. 154.

2 This principle is applicable alike to individuals and to the
various races of men. Origin and Character of the British People,
by N. C. Macnamara. Also by the same author, The Evolution
of Purposive blatter, p. 191.

Hereditary Nature of Instincts 185

moulded into all that could be desired showed
by their subsequent behaviour that their heredi-
tary instinctive qualities had only been subdued
when children, and by no means eliminated.
The unreliable, sly child, when he reached the
prime of life, in too many instances was an un-
trustworthy and scheming individual, and so on
with the other instinctive faculties.1

In spite, however, of these somewhat pessi-
mistic views as to the permanent results to be
obtained by the ordinary means employed to
educate young children, we are convinced that
if a healthy child is adequately fed and placed
in a fairly favourable environment, many of his
more desirable instinctive qualities may be de-
veloped, such, for instance, as those of parental
affection, respect for superiors, sympathy, and
disinterestedness, out of which an individual's
moral sensibilities are derived. In like manner
we can regulate, but cannot abolish, an indi-
vidual's undesirable hereditary tendencies, such

1 The branch of science known as bio-chemistry has within
recent years shown that effective states of mentality depend much
on the circulation in the blood of certain materials derived from
the ductless glands of our bodies, the destruction of one or other
of the glands being followed by various abnormal conditions of
the nervous system. See also p. 21.

1 86 Instinct and Intelligence

as those of fear, jealousy, envy, hatred, and
malice, qualities which ancient philosophers
fully recognised as forming a part of human
nature which no device of man could wholly
eradicate, a residuum of the wild beast, liable
at any moment to assert itself, a fact of every-
day experience, and one which history has over
and over again proved to be true.1

Before undertaking the care and training of
a child it is desirable, as far as possible, to gain
sound ideas concerning his hereditary qualities
or natural disposition. There are two main
sources from which to obtain information on
this subject; we know the child inherits many
of the qualities possessed by his immediate pro-
genitors; and from about the third year of child-
life his hereditary qualities will be recognisable
from his behaviour, which we can study without
difficulty.

Most people belonging to the upper and
middle classes of society are capable of forming
fairly correct ideas regarding their own heredi-
tary qualities which, if they understood the im-

1 When making use of the term "young children" we mean
children from some three t' five or six years of age, the psychical
nervous substance of whose brains is gradually being matured.

Instinctive Actions 187

portance of the subject, they would utilise in
the training of their own children and in guiding
those to whom they entrust their care.1 It has
been our aim to show that instinctive action is
phylogenetically both older, and often to be
relied on with greater confidence, in the common
affairs of life than conclusions reached by in-
tellectual processes. In the case of many
women their instincts have been, and always
will be, their true and unconscious guide to
action; it is this which confers on them the
exasperating sway of often being in the

1 In an article published in the Westminster Review for
December, 1900, p. 638, on the importance, from an educational
point of view, of rightly understanding .the development of the
innate character of young people, we endeavoured to show that
parents, guided by their own experience, can comprehend the
nature of the inherited mental qualities of their own children, and
are bound to make use of this knowledge in their home training.
The same principle, in our opinion, applies with even greater force
to the case of schoolmasters, many of whom receive lads from
eight to ten years of age under their charge. A master has seldom
any real knowledge as to the innate qualities of the lads he under-
takes to educate; he may make inquiries from a boy's parents as
to the infantile diseases from which his pupil has suffered, but it
rarely occurs to him to inquire concerning the boy's disposition.
If any thought is given to the subject, it is taken for granted that
the lad's character will soon make itself manifest by his conduct.
There is much truth in this idea. Nevertheless, we are convinced
that if parents and masters came to an understanding as to the
real innate and fixed character of the boys they have to deal with,
it would assist much in right education. Not a few self-respecting
natures are in early life driven into habits of sullenness, deceit,
and untold anguish by treatment and punishment misapplied from
ignorance and want of appreciation of a lad's character.

1 88 Instinct and Intelligence

right in matters which reason fails to solve
correctly.

As it is with the lower animals, so
also in the training of young children ; it
should be commenced early in life — that
is, when the child has reached his third
year of age — and to be effective the nurse
or any other person entrusted with the care
of a child ought to possess an innate love for
children. Such a person would soon acquire,
from a child's ordinary behaviour, a fairly
accurate idea of his hereditary instinctive quali-
ties; this knowledge should be fortified by in-
formation on this subject derived from the
child's parents, and, if possible, supplemented
by an acquaintance with the elements of the
physiology of the central nervous system, such,
for instance, as that to be found in Huxley's
small work on this subject; the object being to
enable those entrusted with the training of a
young child's character to realise the nature of
the living matter with which he has to deal, and
the importance of employing appropriate stimuli
to his various sensory organs in order to develop
what is good and suppress any evil qualities

The Training of Instincts 189

possessed by the child. Armed with knowledge
such as this, a nurse or teacher will soon gain
by the exercise of patience, justice, and unfail-
ing kindness, the affection and confidence of a
child, and may then proceed to guide his innate
qualities into correct modes of action.

A young child should be allowed freedom of
action in order to give full play to his natural
tendencies, guided as they ought to be by the
kindly precepts and example of those entrusted
with his management; through liberty a child
comes to recognise the extent of his own
strength and weakness, and thus learns a self-
discipline and consideration for the feelings of
other people which by practice become habitual,
and constitute a sound foundation on which to
rear a satisfactory moral character.

Parental affection is a strongly developed
instinctive faculty. It is the greatest possible
help to a child to feel that his parents take a
genuine interest in him, being at all times ready
to help him in his real or imaginary troubles, and
to participate in his pleasures. The simple
prayers learnt by a child at his mother's knees
are for him no mere repetition of words, but the

i go Instinct and Intelligence

means of developing his innate striving for
communion with a Being upon whose love and
tender care he unconsciously relies, and in
after-life transfers to a supremely wise and lov-
ing spirit — his God. Reserve on the part of
parents, or on the other hand of children, is
often attributed to shyness, but in truth as a rule
depends on the play of a far more difficult in-
stinct to deal with successfully — that is, pride.
It is, however, beyond our province to attempt
to enter into details concerning the training of
young children, the more so as it is within our
power to recommend to the reader an excellent
work on this subject written by Edith Reed
Mumford, under the title of The Dawn of
Character i a Study of Child Life}

Having given the reasons which lead us to
conclude, that the basal ganglia constitute the
basic substance on the working of which instinc-
tive character or behaviour of an individual
mainly depends, we pass on to consider that
part of education which is principally con-

1 M. A. Wood's book, Thoughts of the Training of Your
Children, is the result of five-and-twenty years' experience ; it
contains much valuable information on the subject and may be
highly recommended.

Development of Psychical Cortex 191

cerned in instructing, or influencing from with-
out the development, and working of the asso-
ciation areas of the neopallium on which we
conceive the occurrence of an individual's intel-
lectual processes depend. This part of the
brain, being of later philogenetic evolution than
its more stable instinctive elements, under the
action of appropriate stimuli more readily
undergoes variations and mutations of struc-
ture; it has developed nervous centres which
not only possess psychical properties, but also
motor centres which control the muscles of
the vocal apparatus, enabling men to think
and to express their thoughts in intelligent
speech.

Whether Froebel's Kindergarten, or the
Montessori system is best adapted for training
the intellectual powers of children attending
our elementary State-supported schools is an
open question ; there can be no doubt as to the
value, especially of the latter system, in helping
to increase the intellectual and physical powers
of children ; the freedom of action inculcated is
of great value, and the employment of the
didactic materials recommended by Madame

i g2 Instinct and Intelligence

Montessori are well devised to promote the de-
velopment of the instinctive and the association
areas of a child's brain.1

The structure and quality of the nervous
substance of all classes of Englishmen are de-
rived from a common Anglo-Celtic stock, and
are therefore amenable to the same kind of
training. The difference between the intellec-
tual qualities of the children of the manual
labouring classes, and their more prosperous
neighbours is not in the innate quality of their
nervous systems, but depends on the difference
in the conditions under which their nervous
matter, and that of their immediate progenitors
has been reared ; in other words, on the environ-
ment in which from infancy to childhood and
adult age most of these people have had to
live.

At the age of fourteen years a lad belonging
to the labouring classes is obliged to leave
school, and endeavour to earn his own living.
Not having been trained how to think or to do
any useful kind of work, he finds it difficult to
get any permanent occupation, and probably

1 The Montessori Method, by Maria Montessori, M.D., p. 216.

Boy Life and Labour 193

wanders from one employer to another during
the following three years of his life, learning
little, if anything, likely to advance his future
career. His earnings are insufficient to enable
him to feed or clothe himself properly, conse-
quently many a lad drifts into the ranks of the
unemployable class.1 That this is not an over-
drawn picture of the career of many town-bred
lads is proved by the result of Mr. Arnold Free-
man's history of seventy- one typical examples
of boy-workers between their fourteenth and
nineteenth years of age. He seems to have had
no great difficulty in obtaining sufficient details
concerning the career of these lads at school,
and of their parentage and home conditions to
enable him to form a fairly accurate opinion as
to their hereditary qualities. Mr. Freeman be-
lieves that the life-history of these seventy-one
individuals is representative of well above a
half of the juvenile population of the City of
Birmingham after they had passed through a
ten years' course of instruction in elementary
State-supported schools. But he rightly lays
stress on the fact that throughout their school-

1 The Nineteenth Certury and After, 1912, p. 962.

N

194 Instinct and Intelligence

days the majority of these young people had
lived in houses defective from a sanitary point
of view, and in an extremely unsatisfactory
environment. The extent and depth of the
home-life differed, of course, from one dwelling
to another, but in none of them was there any
real assistance given to forward the work of the
school.

Mr. Freeman found that three years after
leaving school only six of these seventy-one
lads had emerged into the position of skilled
workmen; forty-four of them were doing un-
skilled work, and twenty-one were unemploy-
able on account of physical or intellectual
inefficiency.1 Much of the physical weakness
under which many of these young people suffer
results from the premature decay of their teeth,
a state of things we conceive, to be mainly due
to the pernicious practice which has sprung up
during recent times, of mothers rearing their
children on various kinds of artificial food and
adulterated cow's milk, in place of feeding
them as nature intended from their own
breasts.

1 Boy Life and Labour, by Arnold Freeman, p. 13.

Boy Life and Labour 195

With regard to farm labourers, we learn
from a report issued by the Board of
Agriculture that many of these men assert,
apart from reading, writing, and arith-
metic, that the education they received at
school had proved to be of no possible use to
them.1

From evidence such as that above given it
appears, that a large percentage of the youths
of this country are at present living under social
and industrial conditions which render them
incapable ; when they have reached the age of
manhood of earning sufficient to support a
wife and family in a clean and comfortable
home.

A certain class of politicians, some fifty years
ago were intent on persuading people that if
the nation would supply the necessary funds to
build school-rooms, and provide the teachers
necessary to give free education to every one of
the children of our labouring classes, poverty
and crime would disappear from the country;
they went so far as to assert that, under a system
of compulsory free education, if any man re-

1 The National Review, August, 1910, p. 937.

N 2

196 Instinct and Intelligence

mained poor he would have only himself to
blame for it. These "radical philosophers"
gained their object, and board schools were
established throughout England, conducted on
the principles advocated by those who brought
them into existence. The system of instruction
thus established, with certain modifications, has
now been at work for forty years, with a result
such as that above indicated. We cannot, how-
ever, altogether agree with those who blame the
teaching provided in the board schools as being
mainly responsible for the existing state of
things ; nor does it seem to us that a system of
" compulsory continuation of education " after
a lad has passed through an elementary school
is likely to improve matters, so long as these
young people are obliged to live in homes such
as those in which a large majority of our labour-
ing classes are, from economical and other
causes compelled to reside. The home and its
environment is at the root of much of the evil
complained of ; let the training followed in ele-
mentary schools be ever so perfect, but little
can be done, so long as most of the children
have to dwell in filthy sunless houses, towards

Education of Labouring Classes 197

moulding them into beings other than such as
those described by Mr. Freeman in his admir-
able work on Boy Life and Labour. What we
require at present is a Government which will
carry through measures calculated to improve
the housing of the poor, to amend our
poor laws, including boy labour; when
this work is accomplished it will be time
to take seriously into consideration the
kind, and scope of instruction to be given
in State-supported elementary schools through-
out the country.

The main object to be kept in view in
educating the children of our labouring classes,
is to mould the instinctive and association
areas of their brains into a form which, under
proper stimuli, will become manifest in a self-
reliant, loyal character, steadfast in honest
good work, in whatever state of life the indi-
vidual may be placed. This purpose, as we
have endeavoured to show, may be accom-
plished by the continued employment in early
childhood of appropriate stimuli through
sensory organs, and thus of securing the co-
ordinate working of the higher and lower

198 Instinct and Intelligence

nervous centres of the brain. The efforts of
our elementary school teachers should be
directed, not so much towards cramming their
pupils with bookwork, but in fitting them to
carry on with satisfaction to themselves and
their future employers, the various kinds of
work they are likely to have to perform during
their subsequent lives. The test of efficiency
on leaving school should be to demonstrate
what a lad or girl can do rather than what he
knows. We are told that the ancient Irish
people were in the habit of handing their
children over for instruction to foster-parents,
who had legal charge of their pupils until they
were seventeen years of age, when a lad was
compelled to return home ; and if it was then
found that he had not become efficient in his
calling, obedient, and otherwise properly in-
structed, the foster-father was heavily fined;
the amount of the fine was given to the pupil,
because, as the Brehon Law states, it was " upon
the pupil the injury of want of learning
has been inflicted." This practice is never
likely to be revived, but there is something
very refreshing in the idea of making the

Classification of Pupils 199

teacher responsible, for the shortcomings of
his pupils.1

In every elementary school a certain number
of the pupils respond readily to the instruction
given them; these lads in after-life will prob-
ably become skilled workmen and earn a fairly
competent living wage. A much larger propor-
tion of the lads attending the school are more
or less inattentive, slow to learn, their instinc-
tive qualities dominating their behaviour; in
after-life they take to various kinds of low-
class labour which, if they are physically strong,
enables them to earn fairly good wages during
prosperous times; otherwise, especially in un-
seasonable weather, they have great difficulty
in making both ends meet. Then we have a
third class of lads who are slow to learn, stupid,
and troublesome to manage; these are those
who in after-life drift from one job to another,
too many of them passing sooner or later into
the class of the unemployed, with all its atten-
dant misery. Of the seventy-one boy labourers
whose histories Mr. Freeman records, twenty-

1 The Story of an Irish Sept, by a Member of the Sept (N. C.
Macnamara), p. 13. See also The Ancient Laws of Ireland,
Vol. II., p. 155.

2OO Instinct and Intelligence

one belonged to this latter class. He states
that they were so deficient in mental, moral, or
physical capacity, and sometimes in all three,
as to make it exceedingly probable that at man-
hood in competition with other adult workers
they would tend to be rejected for regular em-
ployment.

Uninteresting and difficult to teach as the
latter class of pupils is, they form a class which
requires the special attention of their teachers.
An inquiry should be instituted regarding the
parents, and hereditary instincts of each one of
such lads, and also into the homes and environ-
ment in which they live ; their teachers, armed
with knowledge of this kind, should, in con-
sultation with the school's medical officer, then
recommend the course of treatment to be
adopted in each case. If insufficient food, a
filthy home, want of sunlight and fresh air are
at the root of the evil, they can only be over-
come by removing a lad into a more salubrious
atmosphere, or by forcing his parents to take
better care of him ; it is hardly likely that con-
finement in a board school for five or six hours
a day would tend to promote the development

Military Training 201

of either his mental or moral powers. It may,
we believe, be safely stated that if in childhood
a boy or girl belonging to the class referred to is
placed under fairly favourable hygienic condi-
tions and properly trained, he or she would
grow up to be a useful member of the working
classes.

By far the majority of lads attending our
elementary State-supported schools are thrown
on their own resources to gain their living after
they have reached the age of fourteen years.
As Mr. Freeman has shown, it is during the fol-
lowing three years that, having no settled
employment, and frequently unwholesome
wretched homes, they too often fall into bad
company and lazy habits, thus as they grow up
to manhood becoming unprofitable members of
society. To avoid this state of things it seems
to us that if within a year of leaving school a
boy has not obtained some fixed and fairly
remunerative employment, he should be com-
pelled to undergo a course of training as a
military cadet or be sent to a training ship;
during these years he should be taught a trade
or some other occupation which would enable

2O2 Instinct and Intelligence

him subsequently to gain a living By treat-
ment of this kind a healthy, well-ordered, and
useful labouring population could be secured,
who, in time of emergency would be ready to
defend their country and in all probability
save it from even the threat of invasion by an
enemy.

APPENDIX

The origin of structural variations in living organisms,
and their adaptability to the environment.

DURING the first half of the nineteenth century
naturalists had become dissatisfied with the then
current ideas regarding the origin of species.
Lamarck completed his well-known work
"Philosophic Zoologique " in the year 1809.
He believed in the spontaneous generation of
living organism from inorganic matter; that
life consists of an order, and state of things
which permit of organic movements, and that
these movements are the result of the action
of a stimulus which excites them. He held that
a progressive change from lower to higher
orders of beings had been and was constantly
taking place, and that to effect these changes
" time and favourable conditions are the two

204 Instinct and Intelligence

principal means which nature has employed in
giving existence to all her productions."

Towards the middle of the last century biolo-
gists, working with improved lenses, advanced
beyond the knowledge (possessed by Tre-
viranus) of the structure and functions of the
cells which, either separately or collectively con-
stitute the bodies of living beings, and came to
recognise the fact, that however complicated the
conditions may be under which vital phenomena
become manifest, they may be split up into pro-
cesses which are identical in their nature with
those taking place in non-living matter.

Sir Charles Lyell, in 1836, although declin-
ing to accept Lamarck's theories regarding the
descent of human beings from anthropoid
ancestors, held that new species originated
through the development of pre-existing
ones.1

Alfred R. Wallace, after spending four years
in South America and some eight years in the
Malay Archipelago in collecting specimens,
and studying the distribution of plants and

1 The Coming of Evolution, by John W. Judd, C.B., LL.D.,
F.R.S., p. 109, Vol. I. of the Cambridge Manuals of Science and
Literature.

The Origin of Species 205

animals, was, in the year 1858, attacked by fever
and confined to his bed. His thoughts wan-
dered to the problem he was engaged in solving
when, as he writes, " in a sudden flash of in-
sight the idea of natural selection presented
itself to my mind.'3 After a few hours' thought
he noted down the views he had formed on the
subject, and forwarded them by the next mail
to C. Darwin, requesting him to show this com-
munication to Sir C. Lyell. Darwin at once
complied with this request, although realising
to the full that this paper of Wallace's fore-
stalled the ideas contained in a work on " The
Origin of Species " he had in hand, and which
he published in the year 1859. In this work
Darwin proved from facts of the most varied
kind, the truth of the idea he had formed regard-
ing natural selection or the survival of the
fittest. He held that animals have descended
from at most only four or five progenitors, and
plants from an equal or lesser number, which
were gradually modified in structure in response
to changes in their environment caused by
geological, climatic, and other influences-
beneficial or harmful. This led him to the

206 Instinct and Intelligence

belief that all animals and plants have
descended from some one prototype. He
states that in consequence of the struggle for
existence any variation however slight, and from
whatever cause it proceeds, if it be in any
degree profitable to an individual of any species
in its complex relation to its environment,
it will tend to protect that individual, and
generally will be inherited by its offspring.
Darwin calls the principle by which each
slight useful variation of an organism is
preserved the principle of natural selection, in
order to emphasise its relation to man's power
of selective breeding. For it is well known
that by careful selection of the stock we can
adapt organic beings to our own use through
the accumulation of slight but useful variations.
Natural selection, however, is a power con-
stantly ready for action, and is as immeasurably
superior to man's efforts as the work of nature
is to that of art.1

Darwin repeatedly insists on the fact, that
natural selection could not be effective unless

1 The Origin of Species by Means of Natural Selection, by
Charles Darwin, M.A., 1859, p. 63.

The Origin of Species 207

very long periods of time were allowed for its
complete action. It is evident that time must
have been an all-important factor if we are to
suppose, that by the interaction of the inherent
properties possessed by the elements of living
matter its structural arrangement became gradu-
ally modified in such a way, that existing classes
of animals and plants have been evolved out
of it.

Charles Darwin's great work on the Origin
of Species was published in 1859, and was fol-
lowed by the first part of Herbert Spencer's
Principles of Biology and Huxley's Man's
Place in Nature, both of which appeared in the
year 1863; the evidence and opinions set forth
in the writings of these three Englishmen gave
a great impetus to scientists engaged in experi-
ment on the influence of mechanical, and other
forms of energy in modifying the character of
plants and animals.

In the sixth edition of the Origin of Species,
published in 1872, Darwin had arrived at the
opinion, that the physical condition of organisms
lead to new sub-varieties without the aid of
selection. In a letter to a friend, dated 1876,

208 Instinct and Intelligence

he observes, "that in my opinion the greatest
error which I have committed has been not
allowing sufficient weight to the direct action of
the environment, i.e., food, climate, etc., inde-
pendently of natural selection. When I wrote
the 'Origin,' and for some years afterwards,
I could find little good evidence of the direct
action of the environment. Now there is a large
body of evidence." In this opinion we fully
concur.

Professor E. Warming, referring to the xero-
philous character of desert plants, observes :
''' The question arises whether these adaptations
to the medium should be regarded as a result
of natural selection, or whether they owe their
origin to the action of the conditions of the
medium in modifying forms exercised directly ;
I adopt the latter view. The character of
adaptation thus directly acquired has become
fixed and hereditary."1

Professor G. Henslow has bestowed many
years of careful study on this subject and
arrived at the conclusion that, we have now
abundant proof both by induction and ex-

1 /Ecology of Plants, p. 373.

The Mutation of Structure 209

periment, that the form and structure of
the organs of plants are due to the immediate
response of living protoplasm to the influence
of the environment, and that it, or rather the
nucleus, builds up just those cells and tissues
which are conformable to the conditions of life.
Then after a few years they become hereditary,
and so fix the varietal or specific characters by
which they are distinguished.1

Mr. R. Ruggles Gates, when referring to this
subject, remarks that " it seems clear that the
plasticity and adaptability of organisms is one
of their main properties which has made evolu-
tion possible ; on the other hand, the ' tenacity '
of heredity in perpetuating even small differ-
ences for long periods is essential if evolution
is to have any cumulative effect." !

The most reliable evidence as to the progres-
sive evolution of the animal kingdom is derived
from a study of their fossil remains in the vari-
ous geological strata of our own and other parts
of the world. The length of time these strata
have taken to form is an open question, but we

1 The Journal of the Horticultural Society, August, 1915.

2 The Mutation Factor in Evolution, pp. 221-321, by R. Ruggles
Gates.

2io Instinct and Intelligence

may be sure that our chalk rocks, for instance,
consist of the shells of marine species of
animals, and that these remains of once living
beings must have taken long periods of time to
have been deposited layer upon layer at the
bottom of the sea. Darwin states that the fine-
ness of gradation in the shells of successive sub-
stages of the chalk formations led him to main-
tain the gradual, as against the sudden evolu-
tion of species. The fossil shells of these rocks
have been thoroughly investigated by Mr.
A. W. Rowe, who observes that "the white
chalk of England offers an almost unique field
for observation on account of its thickness (con-
siderably over 1,000 feet), its slow, uniform, and
continuous deposit in a sea of moderate depth,
with no closely adjacent land, the abundance
and wonderful state of preservation of its
fossils, together with the facility with which
they can be cleared of their chalky covering."
Among the most common chalk fossils is the

o

flattened heart-shaped Sea-Urchin. These are
first found in their shelled sparsely ornamented
forms, from which spring as we ascend the
zone all the other species of the genus. The

Adaptability of Organisms 211

progression is unbroken and minute in the last
degree. We can connect together into con-
tinuous series each minute variation, and each
species of a gradation of structure so insensible
that not a link in the chain of evidence is want-
ing. The bearing of this evidence upon the
question of continuity or discontinuity in evolu-
tion is of paramount importance. Nowhere has
evidence been collected so fully as in the case
of the white chalk; nowhere have such con-
clusive proofs of continuity in evolution been
established.

Prof. W. B. Scott, referring to the evolution
of the existing species of horses, states that
in the Lower Tertiary deposits of North
America each one of the different Eocene and
Oligocene horizons has its characteristic genus
of horses, showing a slow, steady progress in
a definite direction. This series of fossils
points to the fact that existing species of horses
are derived from individuals less highly cap-
able of evading enemies and obtaining food ;
that is, they point to progressive improvement
through long periods of time in the structural
arrangement of this species of animals.

2 1 2 Instinct and Intelligence

Again, the well-known fossil of Archaeopteryx
found in a series of slates in Germany, seems to
constitute a link between groups now widely
separated by divergence in evolution from the
same ancestors. This animal is at once a
feathered flying reptile and a primitive bird
with many reptilian structures. Although
Achaeopteryx was a primitive bird, it is in a
true sense a " link " between reptiles and the
group of modern birds; the gap between these
types is filled up by fossil forms like Hesper-
crnis, whose remains are found in strata of a
later date. That these links are not alone is
proved by the numerous other examples known
to science, such as those which connect
amphibia and reptiles, ancient reptiles and
primitive mammals, as well as those which
come between the different orders of certain
vertebrate classes. The important element in
these examples of evolution is, first, their
adaptation; secondly, the origination of new
parts ; and, thirdly, the retention of the better
invention.

Another kind of evidence favouring the idea
of the progressive evolution of human beings

Mutation of Organisms 213

from simpler orders of animals is the presence
of what are known as non-functional vestigial
structures, relics of past phases of existence
such, for instance, as the unused external
muscles of our ears and rudimentary third eye-
lids, the gill clefts of reptiles, birds, and
mammals, and the hind limbs in whales. The
study of these vestigial structures is of import-
ance in showing that ancestral features have a
great power of hereditary persistence. Our
firm conviction is, that the origin of variations
in the structure of organisms is, in every case,
due to the power which their protoplasmic basic
substance possesses of responding to the action
of the environment. Those organisms which
thus become most perfectly adapted to external
and internal stimuli, are those which survive in
the struggle for existence.

INDEX

Afferent and efferent nerve fibres,
98

Amoeba, their instinctive be-
haviour, 22

Amphioxus, its nervous system,
100

Ants, their instinctive behaviour,

85

Articulate language, 143, 163, 191
Association areas of the brain,
131, 133, 150, 158,
162, 171, 191
of human beings, 148
their development, 98,

105, 109, 119, 141
of monkeys, 141, 148
processes, 158
Associative memory, 159
Atom and molecules, arrangement

of elements, 10
Auditory sensory organs, 63
Automatic action suffices for life

of lower animals, 94
Basal ganglia, their origin, 76,

82, 98, 103, 104, 115
instinctive function of, 104,

106, 113, 117, 133
effect of removal in frogs,

114, 117
effect of removal in dogs,

133
constitute the root and stem

of cerebrum, 98
of birds, 123
fish, 114

human beings, 103, 141
influence of training on, 183
hereditary nature of, 113
relation of to neopallium, 119
Birds and their instinctive be-
haviour, 123, 124
Boy-life and labour, A. Freeman's

account of, 193

Brain, development of from ecto-
derm in worms, 68

Brain, development of in crayfish,

. 77

its construction, 99, 103
Bridgeman, Laura, history of, 151
instinctive behaviour of, 152
influence of defective sensory

organs, 155

Cerebral cortex of birds, 123
hemispheres, effect of removal

in frogs, 117

effect of removal in dogs, 133
impairment of in human

beings, 141

in prehistoric man, 143
their sulci, 129

their development in reptiles,

120 ; in human beings, 139

Character, depending on action of

basal ganglia, 78, 82, 104, 133

influence of neopallium on, 133

environment on, 200
Children and effective training,

186, 197

their hereditary instincts, de-
velopment of, 188
freedom of action, importance

of, 189

Chlorophyll, 16
Cnidocils, 36

Conservation of energy, 13
Corpus striatum,its functions, 10371
Darwin, on origin of species, 205
Sir Francis, on mnemic im-
pressions, 26
Duckbills' sensory impressions,

128
Education (see Preface)

of instinctive processes, 177
of intellectual processes, 158,

162, 164
depends on training of basic

cerebral substance, 176
of animals, 182

applied to human beings,
184

Ind

ex

215

Kducation of young children, 177
of boys of the labouring classes,

influence of environment on, 201
Knergy, 12

Fish, their central nervous sys-
tem, 97
mid-brain and basal ganglia,

103
behaviour in relation to basal

ganglia, 104
possess rudimentary neopallia,

105, 107

their nest-building and instinc-
tive powers, no

Forel, on the senses of insects, 87
Freeman, Arnold, on boy-life and

labour, 197
Germ cells, 29
Hereditary qualities in reference

to education, 167, 184, 186
Home life, influence on educa-
tion, 194

Hormones, 21, 185 n.
Human beings and hereditary in-

instincts, 186

Huxley on metabolic changes, 17
on physical basis of memory, 26
Hydroids, their structure, 34

development of tactile organs,

35

development of nerve cells, 36
behaviour under action of

stimuli, 43

movements are instinctive, 46
Ideas, nature of, 158
their contents, 160
association of, 162
of personality, 171
Idiots, defective nerve cells of

their brains, 144, 146
cerebral hemispheres, 147
Insects, sensory organs of, 83
their reflex nervous system, 89
memory of, 89
Instinct, a fundamental property

of living matter, 21
Instinctive behaviour defined, 19
of ants, 89

Instinctive behaviour of star-fish,

61

of worms, 71
of higher animals, 136
suffices for existence of lower

animals, 93
insufficient existence of higher

animals, 124

Lloyd Morgan's opinion re-
garding, 20, 51, 122, 123
W. McDougalPs opinion re-
garding, 81, 140 n.
in young children, 167
depends on action of basal

ganglia, 168
inherent in human beings,

170, 179

modified by training, 185
elements of nerve cells, 36, 51-2
Intellectual processes, 155, 157, 159
modifies instinctive action,

162, 172, 177
Intelligence in relation to cerebral

cortex, 108, 158
in relation to perfection of neo-

pallium, 148
of human beings, 150
Jennings (Prof.) on behaviour of

amoeba, 24
Keller, M., History of, 155

new instinctive and intellectual

processes, 157
Kinetic energy, 13
Living matter acts as a trans-
former of energy, 15, 17
its fundamental properties, 26
its metabolic changes, 17
of nerve cells, 51
of sensory organs, £53
McDougall, A., on instinctive be-
haviour, 140 n.
Medusoids, their structure, 30

nervous system and sensory

organs, 40, 41
behaviour under actions of

stimuli, 47
action of their sensory organs,

47
their rhythmical movements, 50

2l6

Index

Memory, its physical basic sub-
stance, 26
of insects, 89
in relation to cerebral centres,

133- 159

Metabolism, its meaning, 17
Mid-brain of lower animals, 82,

98, 103, 106
Molecules and atoms, effect of

change in their elements, 10
Mumford, E. R., on the dawn of

character, 108, 190
Ncopallium, defective in idiots,

146
effect of degeneration of, 162,

167

imperfect in infants, 186
a reflex analyser, 176
its origin and development, 105,

109, 119, 130
functions of basic matter, 104,

141

rudimentary in lower verte-
brates, 106

development of in reptiles, 120
association areas of, 150, 157
large size of in human beings,

141, 148
developed through exercise of

sensory organs, 149
and memory, 117
Nerve cells in hydroids, 35, 36

description of, 96
Nervous system of medusoids, 40,
48 ; of worms, 68 ; of starfish
and crayfish, 58, 77 ; of insects,
81 ; of fishes and lower animals,
98, 102 ; of primates, 148
Pithecanthropus erectus, 142
Potential energy, 14
Prof. Pawlow on higher nervous

functions, 176

Protoplasm, its inherent proper-
ties, 17, 25 ^

tesponse to stimuli, 20, 26, 28
response to environment, 27, 36,
37

Protoplasm, physical basis of

memory, 26

a transformer of energy, 14
of nerve cells, 51

possesses mnemic and in-
stinctive elements, 52
Purposive movements of insects,

89

Reflex action in hydroids, 60, 64
in insects, 89

"conditional" of Pawlow, 174
Sensory org'ans in hydroids, 35 ;
in medusoids, 40 ; in crus-
tacea, 75 ; in insects, 86 ;
their relation to cerebral de-
velopment, 151 ; training
through means of, 155, 184
impressions and psycho-instinc-
tive processes, 152
Shaw Bolton on association pro-
cesses, 164

Skulls of prehistoric men, 142
Soddy, F. (Prof.), on energy, 12
on development of eyes of

human beings, 56
Spinal cord and nerves, 97
Starfish, their structure, 58
nervous system, 59
instinctive behaviour, 61
Stentor caeruleus, movements of,

under stimuli, 27
Stimuli in reference to reflex

action, 20

Training of young children, 186
E. R. Mumford on, 190
M. A. Wood on, 190 n.
boys of the labouring classes,

195

Volvocinse and their germ cells, 29
Washburn, M. F., on the animal

mind, 80, 1 16, 121
Worms, the development of brain

from the ectoderm, 68
their nervous system, 69

instinctive behaviour, 71
Yerkes (Prof.), his labyrinth
method, 79, 115

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