28. If, then, certain alterations in the organic conditions are

accompanied by a suppression or perversion of some modes of

Sensibility, without suppressing the rest, it is but rational to

suppose that profound disturbances of the organic mechanism, such

as must result from the removal of the brain, will also suppress or

pervert several modes of Sensibility, and yet leave intact those

modes which belong to the intact parts of the mechanism. Assuming

that the spinal centres with the organs they innervate are capable of

reacting under certain modes of sensation, these will not necessarily

be suppressed by removal of the brain--all that will thereby be

suppressed is their co-operation with the brain. I know it will be

said that precisely this co-operation is necessary for sensation; and

that the spinal reactions are simple reflexions in which sensation has

no part. This, however, is the position I hope to turn. Meanwhile my

assumption is that sensation necessarily plays a part in the reflex

actions _of the organism_, and when that organism is truncated, its

actions are proportionately limited, its sensations less complex. The

spinal cord, separated from encephalic connections, cannot react in the

special forms of Sensation known as color, scent, taste, sound, etc.,

because it does not innervate the organs of these special senses, nor

co-operate with their centres. But it can, and does, react in other

modes: it innervates skin and muscles; and the sensibilities, thus

excited, it can also _combine_ and _co-ordinate_. It has its Memory,

and its Logic, just as the brain has: both no longer than they are

integral parts of an active living organism: neither when the organism

is inactive or dead. We do not expect the retina to respond in sounds,

nor the ear to respond in colors: we expect each organ to have its

special mode of reaction. What is common to both is Sensibility.

What is common to brain and cord is Sensibility--and the laws of

Grouping. Instead of marvelling at the disappearance of so many modes

of Sensibility when the brain is removed, our surprise should be to

find so many evidences of Sensibility remaining after so profound a

mutilation of the mechanism.

29. The current hypothesis, which assumes that the brain is the sole

organ of the mind, the sole seat of sensation, is a remnant of the

ancient hypothesis respecting the Soul and its seat; and on the whole

I think the ancient hypothesis is the more rational of the two. If the

Soul inhabits the organism, using it as an instrument, playing on its

organs as a musician plays on his instrument, we are not called upon

to explain the mode of operation of this mysterious agent; but if the

Soul be the subjective side of the Life, the spiritual aspect of the

material organism, then since it is a synthesis of all the organic

forces, the consensus of all the sentient phenomena, no one part can

usurp the prerogatives of all, but all are requisite for each. And

this indeed is what few physiologists would nowadays dispute. In spite

of their localizing sensation in the cerebral cells, they would not

maintain that the cerebral cells, nor even the whole brain, could

produce sensation--if _detached_ from the organism; the cheek of the

guillotined victim may have blushed when struck, but who believes that

the brain felt the insult, or the blow? Obviously, therefore, when we

read that thought is “a property of the gray substance of the brain, as

gravitation is of matter,” or that the brain is the exclusive organ of

Sensation, the writers cannot consistently carry out their hypothesis

unless they silently reintroduce other organs as co-operating agents;

for a neural process in the cerebrum is _in itself_ no more a

sensation than it is a muscular contraction, or a glandular secretion:

the muscles must co-operate for the contraction, the gland for the

secretion, the neural process being simply the exciting cause. In

like manner the Sensorium is necessary for the sensation, the neural

process--in cerebrum, or elsewhere--being simply the exciting cause.

30. And what is the Sensorium? A long chapter would be required

to state the various opinions which have been held respecting its

_seat_, although amid all the disputes as to the organ, there has been

unanimity as to the function, which is that of converting stimulations

into sensations. I cannot pause here to examine the contending

arguments, but must content myself with expounding the opinion I hold,

namely, that the Sensorium is the _whole_ of the sensitive organism,

and not any one isolated portion of it. When light falls on the optic

organ, or air pulses on the auditory organ, the reaction of each organ

determines the _specific_ character of the sensation, _but no such

sensation is possible unless there be a reaction of the organism_;

and the nature of the product will of course vary with the varying

factors which co-operate--a simple organism, a truncated organism, an

exhausted or otherwise occupied organism, will react differently from

a complex, a normal, or an unoccupied organism. Detach the optic organ

with its centre from the rest of the organism, and no normal sensation

of Sight will result from its stimulation; and in a lesser degree this

is equally true of a stimulation of the optic organ when the sensorium

is exhausted, or powerfully affected by other stimuli. Because of the

great importance of the cerebrum, and its predominance in the nervous

system, it has been supposed to constitute the whole of the sensorium,

in spite of the evidence of varied Sensibility after the cerebrum has

been removed. I do not wish to understate the cerebral importance (see

p. 166), yet I must say that the modern phrase _cerebration_, when

employed as more than a shorthand expression of the complex processes

which a cerebral process initiates, and when taken as the objective

equivalent of Consciousness or of Thought, seems to me not more

justifiable than to speak of Combustion as the equivalent of Railway

Transport. The railway wagons will not move unless the fuel which

supplies the boiler be ignited; the organism will not think unless the

cerebrum excites this peculiar mode of Sensibility by its action on

the organs. _It is the man, and not the brain, that thinks_: it is the

organism as a whole, and not one organ, that feels and acts.

31. Consciousness, or Sensation, is a complex product not to be

recognized in any _one_ of its factors. Cerebral processes and spinal

processes are the elements we analytically separate, as muscular

contractions are the elements of limb-movements. The synthetic unity

of these elements is a reflex; this we analytically decompose into

a sensation and a movement; and then we speak of sensation as the

reaction of the sensory organ, the movement as the reaction of the

muscular organ. By a similar procedure we separate the stimulation of

a sensory nerve from the reaction of the sensory organ, and that from

the reaction of the sensorium; and in this way we may come to regard

Cerebration as Thought. But those who employ this artifice should

remember that the organism is not an assemblage of organs, made up of

parts put together like a machine. The organs are differentiations of

the organism, each evolved from those which preceded it, all sharing in

a common activity, all _inter_-dependent.

32. That co-operation of the Personality which is conspicuous in

conscious actions is also inductively to be inferred in sub-conscious

and unconscious actions. We know that a man reacts on an impression

according to his physical and mental state at the moment--that through

his individuality he feels differently, and thinks differently from

other men, and from himself at other epochs, and in other states.

Because he resembles other men in many and essential points we

conclude that he will resemble them in all; but observation proves

this conclusion to be precipitate. Other men see a blue color in the

sky, or feel awe at sight of the setting sun; but he has perhaps

not learned to discriminate this sensation, is not conscious of the

blue; nor has he learned to feel awe at the setting sun. Why--having

normally constructed eyes--does he not see the blue of the sky? For the

same reason that a dog, or an infant, fails to see it. The color has

no _interest_ for him (and all cognition is primarily emotion), nor

has this want of personal interest been rectified from an impersonal

source: he has never been taught to distinguish the color of the sky;

and his eye wanders over it with the indifferent gaze with which a

savage would regard a Greek codex.

33. The point here insisted on, namely, that every reaction on an

impression is indirectly the reaction of the whole organism, and that

no organ detached from the organism has more significance than a word

detached from a sentence, is of far-reaching importance, and peculiarly

worthy of attention in considering the Reflex Theory, because almost

all the evidence urged in support of that theory presupposes the

legitimacy of concluding what takes place in the organism from what

is observed in an organ detached from its normal connections. No

experimental proof is necessary to show that many actions take place

unconsciously; the fact is undisputed. But does unconsciously mean

insentiently? It is certain that the unconscious actions take place in

a sentient organism, and involve organic processes of the same _order_

as the actions which are conscious. It is also certain that many

sentient processes take place unconsciously. For thousands of years men

used their eyes, and saw as their descendants see, yet were unconscious

of the blue sky and green of the grass. Were their visual reactions

not of the same _order_ as our own? So far as the optic apparatus

is concerned, there cannot be a doubt on the point; yet in them the

sensorium having a somewhat different disposition--the neural elements

being differently combined--their reactions correspondingly differed.

They too had optical Sensibility, and visual sensations; but they did

not feel precisely what we feel.

34. I have chosen these somewhat remote illustrations for the sake of

their psychological interest; but I might have confined myself to more

familiar examples. Thus the contents of the consciousness of a man born

blind cannot be _the same_ as the contents of one who has had visual

experiences, which will enter into the complex of every conscious

state, because the visual organs will have affected his sensorium;

nevertheless in the organism of the blind man there are conditions

so similar to those of other men, and his experiences will have been

so similar, that in spite of the modifications due to the absence of

visual experiences, his consciousness will in the main resemble theirs.

But now let us in imagination pursue this kind of modification, let us

take away hearing, taste, and smell, and we shall have proportionately

simplified the contents of consciousness--the reactions of the

sensorium--in thus simplifying the organism. There still will remain

Touch, Temperature, Pain, and the Systemic Sensations. There will still

remain an organism to react on impressions. So long as there is a

living organism, however truncated, there is a sentient mechanism. When

the brain has been removed, the removal causes both a _disturbance_ of

function and a _loss_ of function; the mechanism has been seriously

interfered with; yet all those parts of the mechanism which still

co-operate manifest their physiological aptitudes. The animal can live

without its brain, _ergo_ it can feel without its brain. Observation

proves this, for it discovers the brainless animal manifesting various

sensibilities, and combining various movements. The vision of the

brainless animal is greatly impaired, but it nevertheless persists.

The intelligence is greatly impaired, the spontaneity is reduced to a

minimum; but still both intelligence and spontaneity are manifested.

35. The physiologist has only two conclusions open to him. Either

he holds Sensation to be a _property_ of nerve-tissue--and in that

case he must assign it to the spinal cord as to the brain; or else

he holds Sensation to be a _function_ of an organ--and in that case,

although analytically he may decompose the organism into separate

organs, assigning special sensations to the reactions of each, he must

still admit that in reality these organs only yield sensations as

component parts of the organism. The notion of a separate organ, such

as the brain, being the exclusive seat of sensation is thus seen to be

untenable.

In popular phrase, “it is not the eye which sees, but the mind behind

the eye.” It is not the stimulus which is the _object_ felt--it is the

change in consciousness--the reaction of the sensorium. No one would

propound the absurdity that the retinal cells _see_, or the auditory

cells _hear_ (although by a conventional ellipsis these cells are said

to be “percipient” of colors and sounds), yet many writers have no

hesitation in asserting that the cerebral cells are the seats of these

and all other sensations. In a hundred treatises may be read the most

precise description of the transformation of molecular changes in the

retinal cells into molecular changes in the cerebral cells, where, it

is said, “we know that the stimulations become sensations.” Now who

knows this? How can it be known? Nay, who, on reflection, fails to see

that this cannot be so? If a sensation of sight were not much _more_

than a molecular change in the cerebrum stimulated by a molecular

change in the optic tract, three conclusions would follow, each of

which is demonstrably erroneous:--

I. The cerebrum in a decapitated animal would respond by a sensation of

sight to a retinal stimulation.

II. The animal deprived of its cerebrum could not respond by a

sensation of sight to a retinal stimulation.

III. The same retinal stimulation would always produce the same

cerebral process and the same sensation; whereas the sensation depends

on the condition of the sensorium at the time.

36. The difference between the Reflex Theory and that here upheld is

important in its general relations, and yet turns on a point which may

easily appear insignificant. The Reflex Theory asserts that when a

sensory nerve is stimulated, the excitation of the centre may either

subdivide into two waves, one of which passes directly to the brain

and there awakens sensation, the other passes over to the motor-roots

and causes muscular contractions; or, instead of thus subdividing, the

wave may pass at once to the motor-nerves, and then there is movement

without sensation. This is obviously a restatement in anatomical terms

of the observed fact that some reflexes take place consciously and

some unconsciously. But what evidence is there for this anatomical

statement? We have seen that there is none. According to all we

actually know, and reasonably infer, the continuity of tissue and the

irradiation of excitation are such that the stimulus wave must always

affect the whole system, so that brain and cord being structurally

united, their reactions must co-operate with varying energy dependent

on their statical conditions at the time.[243]

37. The physiological fact that the irradiation is _restricted_ to

certain paths, and therefore only certain portions of the whole system

are excited to discharge--the fact that stimulation takes effect along

the lines of least resistance--is that which gives the Reflex Theory

its plausible aspect. But this fact of restriction is not dependent on

an _anatomical_ disposition of structure, it is, as we have already

seen (PROBLEM II. § 166), dependent on a fluctuating physiological

disposition--a temporary statical condition of the centres. And it

enables us to understand why the reflex action which is at one moment

a distinctly conscious or even a volitional action, is at another

sub-conscious or unconscious. When an object is placed in the hand of

an infant the fingers close over it by a simple reflex. This having

also been observed in the case of an infant born without a brain,[244]

one might interpret it as normally taking place without brain

co-operation, were there not good grounds for concluding that normally

the brain must co-operate. Thus if the object be placed in the hand of

a boy, or a man, the fingers will close, or not close--not according to

an anatomical mechanism, but according to a physiological condition:

if the attention preoccupy his sensorium elsewhere, his fingers will

probably close, probably not; if his sensorium be directed towards the

object, either by the urgency of the sensitive impression, or by some

one’s pointing to the object, the fingers will close or not close,

just as he chooses--perhaps the hand will be suddenly drawn away. The

centre of innervation for the fingers is in the cord, and from this

comes the final discharge of the sensitive stimulation; but the neural

processes which preceded this discharge, and were consequent on the

stimulation, were in each case somewhat different. In each case the

impression on the skin was carried to the cord, and thence irradiated

throughout the continuous neural axis, restricted to certain paths by

the resistance it met with, but blending with waves of simultaneous

excitations from other sources, the final discharge being the resultant

of these component forces. We may suppose the brain to be the seat

of consciousness, and yet not conclude that the brain was unaffected

because the fingers closed unconsciously; any more than we conclude

that the retina of the unoccupied eye is unaffected by light when with

the other we are looking through a microscope, and only _see_ objects

with this eye--though directly we attend to the impressions on the

other eye we see the objects which before were unseen. We know that the

muscles of the back are all involved in walking, standing, etc., but we

are seldom conscious of their co-operation till rheumatism or lumbago

makes us painfully alive to it.

38. The two main positions of the Reflex Theory are, 1°, that

reflex actions take place without brain co-operation,--as proved by

observation of decapitated animals; 2°, that they take place without

brain co-operation,--as proved by our being unconscious of them.

To these the answers are: 1°. The proof drawn from observation of

decapitated animals is defective, because the conditions of the

organism are then abnormal--there is a disturbance of the mechanism,

and a loss of some of its components. The fact that a reflex occurs

in the absence of the brain is no proof that reflexes when the brain

is present occur without its participation. 2°. The absence of

consciousness cannot be accepted as proof of the brain not being in

action, because much brain-work is known to pass unconsciously, and

there are cerebral reflexes which have the same characters as spinal

reflexes.

39. A prick on the great toe traverses the whole length of the spinal

axis with effects manifested in various organs--the muscles of the

limb, the heart, the chest, the eyes, etc. The leg is withdrawn,

the heart momently arrested, the eyes turned towards the source of

irritation, the thoughts directed towards relief. These effects can

be observed--there are others which lie beyond our observation, and

can only be revealed by delicate experimental tests. But even the

observable effects are very fluctuating, because they depend on

fluctuating conditions. All we can say is, that so long as there is

continuity of structure, there must be continuity of excitation;

and the brain structurally connected with the centre of a sensory

impression, must necessarily co-operate more or less in the reactions

of that centre. In other words, the brain, although not the exclusive

seat of sensation, plays a part in every particular sensation, so long

as it forms a part of the stimulated organism.

40. This view being so widely opposed to the views current in

physiological schools, I was gratified to find Dr. Crichton Browne led

by his researches to a conclusion not unlike it in essential features.

In his essay on the Functions of the Optic Thalami[245] (well worthy

of attention on other grounds) he says: “Allowing the spinal cord a

power of independent action, it may still be that it generally acts

reflexly through, or in association with, a superior centre. The

sensorial ganglia can undoubtedly act alone in a reflex manner, but

they almost invariably consult the cerebrum before dealing with the

impressions which they receive; so it may be that the spinal cord,

though capable of spontaneous reaction, may yet commonly refer to some

higher seat of compound co-ordination before sending forth an answer

to any message brought to it.” What is here stated as a possible and

occasional process, I consider to be a necessary and universal process.

Dr. Browne acutely remarks that if “what may be termed the encephalic

loop were an integral part of every reflex act, then the influence of

an intracranial lesion in checking reflex action would not be difficult

to understand”--and we may add the notorious influence of the brain in

arresting reflex actions, and modifying them by the will, which is only

explicable on the supposition that the cerebral and spinal centres are

functionally associated. Dr. Browne further remarks: “In experimenting

upon myself I have sometimes thought that when the toe is pricked the

sensation of pain actually precedes the movement of withdrawal; and

in experimenting upon patients with sluggish nervous systems I have

certainly noticed that after the pricking of the toe the little cry of

pain has anticipated the muscular contractions of the leg. Now this cry

of pain is a secondary reflex act through the sensorial centre; it is

the result of a discharge from efferent nerves from the summit of what

we have spoken of as the encephalic loop line; and we should certainly

not expect that it would be developed earlier than the primary

reflexion upon the motor apparatus, unless indeed what we have regarded

as the primary reflexion really itself took place by way of the loop

line.”

41. The difference between a voluntary and involuntary act is not, I

conceive, that in the one case the brain co-operates and in the other

is inactive, but that while in both the brain co-operates, the state

of the sensorium known as mental prevision or ideal stimulation, is

present in the one, and absent or less conspicuous in the other. So

likewise the difference between a normal reflex action accompanied, and

the same action unaccompanied by consciousness, is not that the brain

co-operates in the one and is inactive in the other, but that the state

of the sensorium is somewhat different in the two cases. Movements

which originally were voluntary and difficult of execution--accompanied

therefore by brain co-operation--become by frequent repetition

automatic, easy of execution, and unconscious--they are then said to

depend on the direct action of the established mechanism. Granted. But

what are the components of this mechanism? Are they not just those

centres and organs which at first effected the movements? In becoming

easy and automatic, the movements do not _change their mechanism_--the

moving organs and the motor conditions remain what they were; all that

is changed is the degree of consciousness, i. e. the _state_ of the

sensorium which precedes and succeeds the movement. It is this which

constitutes the difficulty of the question. Some readers may consider

that all is conceded when unconsciousness is admitted. But this is

not so. My present argument is the physiological one that the brain

co-operates in reflex actions whenever the brain is structurally united

with the reflex centres; the psychological question as to whether

consciousness is also involved in this brain co-operation must be

debated on other grounds; and we have already seen that consciousness

operates in gradations of infinite delicacy.

Observe a man performing some automatic action, such as planing a

deal board, or cutting out a pattern, which he has done so often that

he is now able to do it “mechanically.” It is certain that his brain

co-operates, and that he could not act thus with an injured brain;

yet he is said to act unconsciously, his brain occupied elsewhere as

he whistles, talks to bystanders, or thinks of his wife and children.

Yet the brain is acting as an overseer of his work, attentive to every

stroke of the plane, every snip of the scissors; and this becomes

evident directly his attention is otherwise absorbed by an interesting

question addressed to him, or an interesting object meeting his eye:

then the work pauses, his hands are arrested, and the automatic action

will only be resumed when his attention is released--when he has

answered your question, or satisfied himself about the object.

42. This is a step towards understanding the co-operation of the brain

even in those connate reflexes which were not originally voluntary

acts, but were from the first organized tendencies, and are capable

of being realized in the absence of the brain. I admit that it is

difficult to find proof of brain co-operation here, though I think

the anatomical and physiological evidence render it highly probable.

But distinct proof to the contrary would not suffice for the Reflex

Theory--would not prove that reflex actions were insentient--unless

there had previously been proved that which seems to me contradicted

by the clearest and most massive evidence, namely, that the brain is

the sole seat of sentience. This contradictory evidence we will now

furnish.

CHAPTER III.

INDUCTIONS FROM PARTICULAR OBSERVATIONS.

43. In the last chapter we surveyed the deductive evidence, from which

the conclusion was that Reflexion necessarily involves Sensibility,

but not necessarily any one particular _mode_ of Sensibility, such

as Consciousness, Pain, Discomfort, Attention, or the reaction of

any one of the special Senses. Although each or all of these modes

may be involved in the sensorial process which determines a reflex

act, each or all may be absent. Such is the fact of observation. This

fact is interpreted on the hypothesis that Reflexion is the exclusive

property of the spinal cord, as Sensation is of the brain. When we

come to examine the evidence for this hypothesis, we find it to move

in a circle: the brain is said to be the exclusive seat of sensation,

because reflex actions can be effected after its removal; and reflex

actions are said to be insentient because they take place in the

absence of the brain.

A gentleman was one day stoutly asserting that there were no

gold-fields except in Mexico and Peru. A nugget, dug up in California,

was presented to him, as evidence against his positive assertion.

He was not in the least disconcerted. “This metal, sir, is, I own,

extremely _like_ gold; and you tell me that it passes as such in the

market, having been declared by the assayers to be undistinguishable

from the precious metal. All this I will not dispute. Nevertheless,

the metal is not gold, but _auruminium_; it cannot be gold, _because_

gold comes only from Mexico and Peru.” In vain was he informed that

the geological formation was similar in California and Peru, and the

metals similar; he had fixed in his mind the conclusion that gold

existed _only_ in Mexico and Peru: this was a law of nature; he had no

reasons to give why it should be so; but such had been the admitted

fact for many years, and from it he would not swerve. He was not fond

of new-fangled notions, which, after all, would only lead us back to

the exploded errors of the past. To accept the statement that gold was

to be found elsewhere than in Mexico and Peru, would be to return to

the opinion of the ancients, who thought there was gold in the upper

regions of Tartary!

Sensation is not tangible, assayable, like gold. We can understand,

therefore, that the very men who would make merry with the

_auruminium_, would accept easily such a phrase as “reflex action.”

The decapitated animal defends itself against injury, gets out of

the way of annoyances, cleans itself, performs many of its ordinary

actions, but is said to do these things without that Sensibility which,

if its head were on, would guide them. Even before the Reflex Theory

was invented this line of argument was used. Gall, referring to the

experiments of Sue, previously noticed, says that “Sue confounds the

effects of Irritability with those of Sensibility.”[246] Not gold, dear

sir, but _auruminium_!

44. On investigating the phenomena we soon come upon two classes which

must cause hesitation. We find that the brain has its reflex processes,

of the same order as those of the cord; we find that these processes

may be conscious or unconscious, voluntary or involuntary; so that we

can no longer separate brain from cord on the ground of Reflexion. In

this respect, at least, the two are mechanisms with similar powers.

Turning now to the other class of phenomena, we find that precisely as

the brain is an organ of Reflexion, the cord is an organ of Sensation.

All the evidence we can have, from which to infer the presence of

sensation, is furnished by the sensorial processes in the cord. Remove

the brain, and the animal still manifests Sensibility, and this in

degrees of energy and complexity proportional to the mechanisms still

intact: some of these manifestations have the character of volitional

actions, some of automatic actions, some of Memory, Judgment, and

selective Adaptation. These we observe not indeed with the energy and

variety of such manifestations when the brain co-operates, since the

disturbance of the organism which is the consequence of the brain’s

removal--or the meagreness of the organism which is the correlative

of the brain never having been developed--must of course involve a

corresponding difference in the observed phenomena; but the point here

brought forward is that phenomena of the same _order_ are manifested by

organisms with or without a brain.

45. Let us go seriatim through the evidence of these two classes:--

CEREBRAL REFLEXES.

While Theory separated the actions of the cord from those of the brain

on the ground of their being at times unconscious and involuntary,

Observation disclosed that this distinction could not be maintained.

This step was taken by Dr. Laycock in 1840. In a striking paper[247]

read by him at the British Association in 1844, he brought together the

evidence on which his view was founded. The idea has been adopted and

illustrated in the writings of Dr. Carpenter, who now calls the action

“unconscious cerebration.”

“I was led to this opinion,” Dr. Laycock says in announcing his view,

“by the general principle that the ganglia within the cranium, being

a continuation of the spinal cord, must necessarily be regulated as

to their reaction on external agencies by laws identical with those

governing the spinal ganglia and their analogues in the lower animals.

If, therefore, the spinal cord is a centre of reflexion, the brain must

also be one.” It is a matter of regret that Dr. Laycock did not extend

this principle, and declare that whatever was true of the _properties_

of the cranial centres must also be true of the spinal centres; if the

brain have Sensibility, the spinal cord must also have it.

Dr. Laycock refers to the curious phenomena of Hydrophobia in proof

that reflex actions may be excited by the optic nerves, or by a mere

idea of water. When a mirror was presented to a patient, the reflexion

of the light acting on his retina, in the manner of a reflexion

from the surface of water, produced a convulsive sobbing, as in the

attempt to swallow water, and the patient turned aside his head with

expressions of terror. Money was given him to induce him to look a

second time, but before he had looked a minute the same effect was

produced.

The _idea_ of water excited similar convulsions. No sooner was it

suggested that the patient should swallow a little water than he seemed

frightened, and began to cry out. By kindly encouragements he was

brought to express his willingness to drink, but the _sound_ of the

water, as it was poured out again, brought on convulsions. In another

case, “on our proposing to him to drink, he started up, and recovered

his breath by a deep convulsive inspiration. On being urged to try,

he took a cup of water in one hand and a spoon in the other. With as

expression of terror, yet with great resolution, he filled the spoon

and proceeded to carry it to his lips; but before it reached his mouth

his courage forsook him, and he was forced to desist. He repeatedly

renewed the attempt, but with no more success. His arm became rigid and

immovable whenever he tried to raise it to his mouth, and he struggled

in vain against this spasmodic resistance.”

In 1843 Griesinger--who appears to have known nothing of Dr. Laycock’s

paper--published his remarkably suggestive memoir on Psychical

Reflexes,[248] in which he extends the principle of Reflexion to all

the cerebro-spinal centres. The whole course of subsequent research

has confirmed this view; so that we may say with Landry, “L’existence

du pouvoir réflexe dans l’encéphale ou dans quelques unes de ses

parties établit une nouvelle analogie entre le centre nerveux cranien

et la moelle épinière.”[249] Indeed we have only to consider the

Laughter which follows a ludicrous idea, or the Terror which follows

a suggestion of danger,--the varying and involuntary expression of

Emotion,--and the curious phenomena of Imitation and Contagion,--to see

how large a place cerebral reflexion occupies.

46. The existence of cerebral reflexion having been thus made manifest,

Dr. Carpenter classed all reflex actions under three heads: 1°, the

excito-motor, determined by the spinal cord; 2°, the sensori-motor,

determined by the ganglia at the base of the brain; 3°, ideo-motor,

determined by the brain. From all these Consciousness is absent. From

the first, he supposes Sensation to be absent. As an artifice, such

a classification may have its value, but it is physiologically and

psychologically misleading. It sustains the hypothesis of an imaginary

excito-motor mechanism. It restricts Sensibility to one of its many

modes. It fails altogether to connect Sensation with Thought, the Logic

of Feeling with the Logic of Signs.

47. The view of Sensibility as common to the whole cerebro-spinal axis

is by no means new. Robert Whytt maintained it. Prochaska held that

the spinal cord formed the greater part of the _sensorium commune_;

and he adduced, in proof, the familiar facts of sensibility manifested

by headless animals. The next writer whom I can discover to have

held this opinion is J. J. Sue,--the father of the celebrated French

romance-writer,--who, in 1803, conceived that his experiments proved

the spinal cord to be capable of replacing, to a certain extent, the

functions of the brain.[250] Next came Legallois,[251] who undertook

to show, by a series of experiments, that the principle of sensation

and movement, in the trunk and extremities, has its seat in the spinal

cord. The mere division of the cord, he said, produces “the astonishing

result of an animal, in which the head and the body enjoy separate

vitality, the head living as if the body did not exist, and the body

living as if the head did not exist. Guinea-pigs, after decapitation,

seem very sensitive to the pain caused by the wound in the neck; they

alternately carry first one hind-leg and then the other, to the spot,

as if to scratch it. Kittens also do the same.”

A few years afterwards, 1817, Dr. Wilson Philip concluded that “the

spinal marrow possesses sensorial power, as appears from very simple

experiments”; but he held the brain to be the _chief_ source of

sensorial power.[252] The following year, Lallemand supported this

opinion by the very curious phenomena exhibited by infants born without

brains: these infants breathed, swallowed, sucked, squalled, and gave

very unequivocal signs of sensibility. The value of such observations

consists in disproving the objection frequently urged against the

evidence of decapitated animals, namely, that in these animals the

spinal cord preserves the remains of a sensibility endowed by the brain.

Longet here places an observation recorded by Beyer. A new-born infant,

whose brain, during the birth, had been completely extirpated (to save

the mother’s life), was wrapped in a towel, and placed in the corner

of the room, as a lifeless mass. While the surgeon was giving all his

care to the mother, he heard with horror a kind of murmur proceeding

from the spot where the body had been placed. In three minutes a

distinct _cry_ was heard. The towel was removed, and, to the surprise

of all, this brainless infant was seen struggling with rapid movement

of its arms and legs. It cried, and gave other signs of sensibility for

several minutes.[253]

In 1828 Calmeil arrived at the same conclusion as that reached by

Legallois, Wilson Philip, and Lallemand. Indeed when, in 1833, the

Reflex Theory appeared, this opinion was so firmly rooted, that

we find Mr. Grainger combating it as the established error of the

day. He takes as much pains to show that physiologists are wrong in

attributing sensation to the spinal cord, as I am here taking to show

that they were right.[254] “It is, indeed, apparent,” he says, “that

the whole question concerning the truth or falsehood of the theory

which attributes the reflex power to the spinal cord hinges upon the

correctness or incorrectness of the received doctrines respecting the

seat of sensation and volition; so that until those doctrines are

proved to be false, it is impossible to establish the hypothesis of Dr.

Hall.”[255]

The reader is requested to take note of this, because when we come to

the evidence which proves the spinal cord to be a centre of sensation,

we shall find that the _only_ ground for rejecting that evidence is the

assumed truth of the Reflex Theory, coupled with the assumption of the

brain being the exclusive seat of sensation. Whereas if the evidence

proves that the spinal cord _is_ a sensational centre, then the Reflex

Theory is destroyed, and cannot be urged against such evidence.

48. Thus many of the facts which prove the sensational function of

the spinal cord were known, and even a vague conception of their real

significance was general, until the Reflex Theory came to explain

all such facts as the results of mechanical adjustment, and of a new

nervous principle called “Reflexion.” For many years this theory has

reigned, and met with but little opposition. Yet the true doctrine has

not wanted defenders in Germany. Nasse[256] denied that decapitated

animals showed no spontaneity; he asserted that they exhibited clear

signs of mental activity. Carus sarcastically pointed out that the

_word_ “reflex” was replacing “irritability,” as a key to unlock all

puzzles; and he took up a position which is very similar to the one

occupied in these pages, namely, that the spinal cord being formed of

gray matter as well as of fibres, it must have sensibility and power of

reacting on nervous stimulus, no less than conductibility; that, in

fact, it is a centre, and must act like all other nerve-centres.[257]

J. W. Arnold opposed the Reflex Theory in a very remarkable little

work, in which he vindicates the claim of the spinal cord as a sensory

and motor centre, although denying to its actions any volitional

character.[258] This was in 1844. Eleven years elapsed without any

further opposition, when Edward Pflüger, in 1853, published his work

on the Sensorial Functions of the spinal cord.[259] In this work he

recurred to the old views of Prochaska and Legallois; but although he

attacked Marshall Hall with merciless severity, he did not point out

the fundamental error of the Reflex Theory, which theory he seems to

accept. Nor did he give his views that philosophical and anatomical

basis which could alone render his interpretations acceptable. Added to

this, the tone of asperity in which his work was written, created some

prejudice against him; and thus, while many admitted his facts, they

rejected his conclusions.[260]

In 1858 Professor Owen read a paper of mine at the Leeds meeting of

the British Association, on “The spinal cord as a centre of Sensation

and Volition,” in which a rapid indication of my point of view, and

an account of some experiments to illustrate it, were given--_not_, I

believe, conclusive to any of the audience. Indeed, the subject was

too vast to be discussed in such a paper; and my object was rather to

excite new inquiry, than to make converts to a view which could only be

embraced after a thorough reinvestigation of the dominant theories.

In 1859 appeared Schiff’s work;[261] and here we find a large space

allotted to the discussion of Pflüger’s doctrine. Schiff, whose

immense experience as an experimentalist, and whose acuteness and

caution every one will highly estimate, frankly pronounces in favor

of the sensational character of spinal actions; but he denies that

they are volitional, and objects strongly to the introduction of

any such idea as that of “psychical activity.” He thinks it utterly

untenable to suppose that impressions have reactions in the brain

which they have not in the spinal cord:--if one has sensibility, the

other must have it; and he thinks that, so far from the actions of the

cord being distinguishable from those of the brain by the character

of “reflexion,” and depending on a mechanical arrangement--_all_

actions, cerebral or spinal, are reflex; _all_ depend on a mechanical

arrangement.[262]

Since that time there has been the remarkable work of Goltz, so

often cited in these pages,[263] and his subsequent experiments on

dogs, which (although he does not decisively adopt the views of

Pflüger) furnish ample evidence that sensation and volition cannot be

exclusively localised in the brain.

49. Heubel’s interesting experiments[264] show that a frog may be

thrown into a state of profound sleep by the withdrawal of all external

stimulation, and in this state will remain lying on its back for hours.

Now this position is one so very uncomfortable that, when awake, the

frog will not retain it a moment, if free to turn round; and when

asleep, a prick on the toe, a sudden noise, or a beam of light will

awaken it, causing it to turn. That is to say, the withdrawal of the

normal stimuli so lowers the sensibility of the frog’s nerve-centres,

that he does not feel the effects of the unusual position, but feels

them directly the centres are stimulated into activity. All this is

intelligible enough on the supposition of the state of sleep being

dependent on a lowering of the cerebral activity. But what shall we

say on learning that precisely the same phenomena are manifested by a

brainless frog? Every one knows that the brainless frog is intolerant

of lying on its back, and immediately turns round, if placed on it. Yet

the brainless frog may be thrown into deep sleep by the same exclusion

of external stimuli; from which he also will be awakened by a prick,

a noise, or a beam of light; and no sooner is he awakened than he at

once turns round. Were the brainless frog incapable of sensation, a

prick on his toe would cause a simple reflex withdrawal of the leg;

but this is not the effect; on the contrary, the stimulus excites the

whole spinal cord, and whatever sensation of discomfort may be caused

by the abnormal position of the limbs in an uninjured awakened frog, is

excited in the brainless frog.

50. I need not swell this chapter with examples of Sensibility in

animals deprived of the brain; many have already been given, and

any text-book of Physiology will supply more. No one disputes the

observations, only the inference that these manifestations were

sentient: they are said to have been merely mechanical reflexes. If,

however, we can detect in them _some_ evidence of what all recognize as

peculiarly characteristic of Mind, the mechanical interpretation will

be less plausible.

At the outset the reader must be warned against exaggerating and

distorting the bearing of my remarks, and must not suppose that I

disregard the vast differences between the Logic of Signs which

belongs to Thought, and the Logic of Feeling which belongs to

Sensation, nor suppose that I look upon the spinal cord as a mental

organ having the _same_ functions as the brain. All that I wish to

establish is the common character of spinal and cerebral processes,

modified as each is by the character of the actions initiated by the

process.

51. This premised, let us begin with the evidence of

DISCRIMINATION.

Although this process is usually regarded as purely psychological, it

must obviously have its physiological side; we find it in Sensation as

in Ideation, and may expect to find it in unconscious as in conscious

processes--in a word, in all sensorial processes whatever. Place a

bit of marble on your tongue, and it will be touched, but not tasted:

the sensations of contact and temperature will excite reflexes, but

little or no reflexes from parotid and salivary glands. A difference in

sensation has a corresponding difference in reflex action; which may be

made evident by removing the tasteless marble, and replacing it by a

pinch of carbonate of lime, i. e. the marble in another state reduced

to a powder: this will excite a sensation of taste, and a secretion

from the glands. In both cases your sentient organism was affected, but

it reacted differently because the difference of the stimulation was

discriminated: consciously or unconsciously, you _felt_ differently.

Again: touch the back of your mouth with your finger, or a feather, and

a convulsive contraction of the gullet responds, followed by vomiting,

if the excitation be renewed. Yet these same nerves and muscles respond

by the totally opposite action of swallowing, if instead of the

stimulation coming from your finger, it come from the pressure of food

or drink.

Analogous experiments on animals without their brains yield similar

results.[265] The salivary secretion and the ordinary reactions of

Taste are provoked by sapid substances. Still more conclusive are the

observations made on a dog whose spinal cord has been divided, and

who therefore according to the reigning ideas is incapable of feeling

any impression made on parts below the section. A pencil inserted in

the rectum causes a reaction of the muscles energetically resisting

the entrance of this foreign body; yet this rectum so sensitive in

its reaction on the stimulus of the pencil, responds by the totally

different reaction--the relaxation of the muscles--on the stimulus of

fæcal matters.

52. “This is all mechanical,” you say? Mechanical, no doubt, as all

actions are; but the question here is whether among the conditions of

the mechanical action Sensibility has a place? The answer can only be

grounded on induction. The actions of the dog are analogous to the

actions which you know were sentient in yourself. There was in both a

discrimination, in both a corresponding reaction. I admit that what is

here called “discrimination” is the application of a logical term to a

mechanical process; I admit that if the spinal mechanism is insentient,

the fact of discrimination may still be manifested; but I conceive

that the many and coercive grounds for admitting that the mechanism is

sentient gain further support in the evidence of discrimination. Every

particular sensation has its corresponding reaction; and although this

has been acquired during ancestral or individual experiences, so that

in the majority of cases there is no consciousness accompanying the

operation, this, as we have seen, is not a valid argument against the

existence of a sensorial process. We have only to lower the Sensibility

of the cord by anæsthetics, or to _preoccupy_ its energies by some

other excitation, and the reaction fails.

MEMORY.

53. “But discrimination, if not a purely physical process, implies

Memory?” No doubt. And what is Memory--on its physiological side--but

an organized tendency to react on lines previously traversed? As

Griesinger truly says: “There is Memory in all the functions of the

central organs, including the spinal cord. There is one for reflex

actions, no less than for sense-images, words, and ideas.” Gratiolet

makes a similar assertion.[266] Indeed if, as we have seen, reflex

actions are partly connate, and partly acquired, it is obvious that the

second class must involve that very reproduction of experiences, which

in the sphere of Intellect is called Memory.

There is assuredly something paradoxical at first in this application

of the terms of the Logic of Signs, yet the psychologist will find

it of great service. But if the terms discrimination and memory

be objected to, they may be replaced by some such phrase as the

“adaptation of the mechanism to varying impulses.” On its objective

side, Discrimination is Neural Grouping; on its subjective side, it is

Association of experiences.

INSTINCT.

54. If we can detect evidences of Volition and Instinct in the

absence of the brain, our thesis may be considered less questionable.

And such evidence there is. Goltz decapitated a male frog (in the

pairing season), and observed that it not only sought, grasped, and

energetically embraced a female, but could always discriminate a

female from a male. Thus when a male frog closely resembling a female

in size and shape was presented to this decapitated animal, he clasped

it, but rapidly let it go again, whereas even the dead body of a

female was held as in a vice. Goltz tried to _delude_ this brainless

animal in various ways, always in vain. Only a female would be held

in his embrace. Goltz then presented a female in a reversed position,

so that the head was grasped by the male. Now here, had there been

simply a reflex machine, incapable of sentient discrimination, the

clutched female would have been held in this position, just like any

other object which excited the reflex; there would have been no “sense

of incongruity,” such as Goltz noticed in his frog, who at once began

a series of movements by which he was enabled, without letting the

female escape, to bring her into the proper position. To render this

observation still more significant, I may add that Goltz did not find

all male frogs act thus--many relinquished the female thus improperly

presented to them. Such phenomena observed in frogs possessing brains,

would be accepted as evidence of sexual instinct and volition.

Further: Goltz removed the brain from a frog, which he then held

under water, gently pressing the body so as to drive the air out of

its lungs; the body being then heavier than the water sank to the

bottom, where it remained motionless. He repeated this procedure with

another frog, not brainless but blinded. This one sank also, but in a

few minutes rose to the surface to breathe. This difference naturally

suggests that the brainless frog was insensible of the condition which

in the other caused a movement of relief. The one felt impending

suffocation, the other felt nothing. Such was the interpretation of a

German friend in whose presence I repeated the experiment. But I had

been instructed by Goltz, and bade my friend wait awhile. He did so,

and saw the brainless frog slowly rise to the surface and breathe there

like his blinded companion. So that the only difference observable was

in the lessened sensibility of the brainless frog.

55. But Goltz records a still more conclusive case. In a large vessel

of water he inverted a glass jar also containing water, which could

then only be retained in the jar by atmospheric pressure. Through the

neck of this inverted jar he thrust a blinded frog, not having pressed

the air out of its lungs. It rose at once in the jar, touching the

inverted bottom with its nose, and when the necessity of fresh air

was felt, the frog began restlessly feeling about the surface of its

prison till an issue was found in the neck of the jar, through which it

dashed into the vessel, and at once rose to the surface of the water

to breathe. In this observation are plainly manifested the stimulation

of uneasy sensation, the volition of seeking relief, and the

discrimination of it when found. If this frog was a sentient mechanism,

what shall we say to the fact that a brainless frog was observed to

go through precisely the same series of actions? Goltz pertinently

remarks: “So long as physiologists satisfied themselves that the

brain was the sole organ of sensation, it was easy to declare all the

actions of the brainless animal to be merely reflex. But now we must

ask whether the greater part of these actions are not due to the _power

of adaptation_ in the central organs, and are therefore to be struck

out of the class of simple reflexes? If I bind one leg of a brainless

frog and observe that he not only sees an obstacle, but crawls aside

from it, I must regard these movements as regulated by his central

power of adaptation; but now suppose I unbind the leg and remove the

obstacle, then if I prick the frog he hops forward. Must I now declare

this hop to have been a simple reflex? Not at all. In both cases the

physiological processes have been similar.”

* * * * *

56. There are no doubt readers who will dismiss all evidence drawn

from experiments on frogs, as irrelevant to mammals and man. Let us

therefore see how the evidence stands with respect to animals higher

in the scale, endowed with less questionable mental faculties. In a

former chapter (PROBLEM II. § 29) we recorded the marked results of

removing the cerebral hemispheres; and at the same time suggested that

these by no means justified the conclusion usually drawn respecting

the hemispheres as the exclusive seat of sensation. And this on two

grounds: First, because the absence of some sensitive phenomena does

not prevent the presence of others: the mutilated organism is still

capable of manifesting Sensibility in those organs which remain intact.

Secondly, because were the mutilation followed by total destruction of

Sensibility, this would not prove Sensibility in the normal organism to

have its seat in the part injured. If the removal of a pin will destroy

the chronometric action of a watch, we do not thence infer that the

chronometric action was the function of this pin. And this objection

has the greater force when we remember that one hemisphere may be

removed without the consequent loss of a single function, and both may

be removed without the loss of several functions usually ascribed to

cerebral influence.[267]

57. Consider the analogous effects of injuries to or removal of

the Cerebellum, in causing disturbance of locomotion, whence the

conclusion has been drawn that the Cerebellum is the exclusive organ

of muscular co-ordination, in spite of the unquestionable evidence

that very many muscular co-ordinations still persist after this organ

is removed. What is the part played by the Cerebellum I do not pause

here to examine.[268] I only say that the movements of swimming,

sucking, swallowing, breathing, crying, micturition, defecation,

etc., are co-ordinated as well after removal of the Cerebellum as

they were before, and that consequently _their_ co-ordination has not

its seat in the Cerebellum. The parallelism is obvious. Removal of

the Cerebrum causes a disturbance in the combination of sensations,

and the execution of certain sense-guided actions, but causes little

appreciable disturbance in others. Removal of the Cerebellum causes

a disturbance in the combination of certain muscular sensations, and

the execution of certain co-ordinated actions, with little appreciable

disturbance in others.

58. So little have the facts been surveyed and estimated in their

entirety that there is perhaps no subject on which physiologists are

more agreed than on the function of the Cerebellum being that of

co-ordination. Yet consider this decisive experiment. I etherized

three healthy frogs, from one I removed the entire cranial centres;

from another I removed only the cerebellum; and, leaving the third

in possession of an intact encephalon, I made two sections of the

posterior columns of the spinal cord. The two first hopped, swam,

used their legs in defence, and exhibited a variety of muscular

co-ordinations, although in both the supposed organ of co-ordination

was absent. Whereas the third, which had this organ intact, and

was capable of moving each limb separately, and each pair of limbs

separately, was utterly incapable of moving all four simultaneously.

Why was this? Obviously because in the first two frogs the motor

mechanism remained intact, and only the cerebral and cerebellar

influence was removed; in the third frog the sensory part of the

motor mechanism had been divided, and no combination of the limbs was

possible.

59. Physiological induction agrees with anatomical induction in

assigning to the cerebrum and cerebellum the office of _incitation_

and _regulation_ rather than of _innervation_; for, as we have seen,

no nerve issues directly from them (PROBLEM II. § 7). Consequently the

effects of injuries to these centres are losses of spontaneity and of

complexity in the manifestations. Inasmuch as in the intact organism

all sensory impressions are propagated throughout the nervous centres,

the reactions of these highest centres will enter into the complex of

every adjusted movement; so the abolition of these centres will be the

dropping of a link in the chain, the abolition of a special element

in the complex group. The organs which are still intact will react,

each in its own way, on being stimulated; but the reaction will be

without the modifying influence of the absent centres. For instance,

the retinal stimulation from a luminous impression normally calls up a

cluster of associated feelings derived originally from other senses,

and a perception of the object is associated with emotions of desire,

terror, etc., according to the past history of the organism, and its

organized reactions, due to hereditary or acquired experiences. It

is these which form the complex feeling discharged in the particular

movement of prehension, or flight. Remove the brain, and there can be

no longer _this_ cluster of associated neural groups excited; there

will be therefore no emotion, simply the visual sensation, and such a

movement as is directly associated with it. The brainless dog moans

when hurt, it does not bark at the cat which it nevertheless sees,

and avoids as a mere obstacle in its path; the cat will cry, it will

not mew. The present pain moves the vocal organs, but does not revive

associated experiences. All those combinations by which a series of

dependent actions result from a single stimulation are frustrated when

the mechanism is disturbed, so that the mutilated animal can no longer

recognize its prey or its enemy, to feed on the one and fly from the

other; no longer builds its habitation, or rears its offspring. It

can still live, feed, sleep, move, and defend itself against present

discomfort; it cannot find its food, or protect itself against

prospective discomfort. We must supply the place of its Intelligence.

We must give it the food, and protect it from injuries.

There is therefore ample evidence to show that what is specially known

as Intelligence is very imperfect after the cerebral influence has been

abolished; but this does not prove the Cerebrum to be the exclusive

seat of Intelligence, it only proves it to be an indispensable factor

in a complex of factors. Still less does it prove the Cerebrum to be

the exclusive seat of Sensation, Instinct, Volition; for these may be

manifested after its removal, although of course even these will be

impaired by the loss of one factor.

60. And here an objection must be anticipated. In spite of the

familiar experience that one mode of Sensibility may be destroyed

without involving the destruction of other modes, there is a

general belief--derived from a mistaken conception of what is really

represented by the unity of Consciousness--that Consciousness

disappears altogether when it disappears at all; and hence, since

Sensation is supposed to imply Consciousness, it also cannot be

divisible, but must vanish altogether if it vanish at all. The first

answer is that Sensation as an abstraction is neither divisible nor

indivisible; but as a generalized expression of concrete sensorial

processes it is reducible to these processes, and divisible as

they are. No one doubts that we may lose a whole class of special

sensations--sight, hearing, pain, temperature, etc.--yet retain all

the others. No one doubts that we may lose a whole class of registered

experiences--forget a language, or lose memory of places so familiar as

the streets of the small town we inhabit, or of faces so familiar as

those of friends and relatives, while the names of these streets and

friends are still remembered when the sounds are heard. Yet sensation

and intelligence are not wholly lost. The mind is still erect amid

these ruins.[269]

61. This premised, let us consider the experimental evidence. Flourens

declares that when he removed the whole of the Cerebrum from pigeons

and fowls, they lost _all_ sensation, _all_ perception, _all_ instinct,

and _all_ volition. They lived perfectly well for months after the

operation, if the food were placed in their mouths; but they never

_sought_ their food; they never _took_ it, even when their beaks were

plunged into it: they could swallow, and digest the grains; but they

had no instinct to make them seek, no volition to make them pick up

the grains. They _saw_ nothing, although the iris remained irritable;

they heard nothing; they could not smell. A state of stupor came on,

resembling that of deep sleep. All voluntary action ceased. If they

were thrown into the air, they flew; if irritated, they moved away; but

if left to themselves, they remained motionless, with the head under

the wing, as in sleep. Now, inasmuch as these effects always ensue

when the Cerebrum is removed, and _never_ when only the Cerebellum is

removed, he concludes that all instincts, volitions, and sensations

“belong exclusively to the cerebral lobes.”

But all experimenters do not agree in other points named by Flourens;

nor in the conclusions he has drawn. On the contrary, it is very

certain, and we find evidence even in Flourens himself, that all

instincts and all sensations are _not_ destroyed by the removal of the

cerebral lobes.

62. Let us hear Bouillaud on this subject.[270] He repeated the

experiment of Flourens, removing the whole of the Cerebrum from

the Brain of a fowl; and he thus records his observations: “This

fowl passes the greater part of her time asleep, but she awakes at

intervals, and _spontaneously_. When she goes to sleep, she turns her

head on one side and buries it in the feathers of the wing; when she

awakes, she shakes herself, flaps her wings, and opens her eyes. In

this respect there is no difference observable between the mutilated

and the perfect bird. She does not seem to be moved at all by the

noise made round about her, but a very slight irritation of the skin

suffices to awaken her instantaneously. When the irritation ceases,

she relapses into sleep. When awake, she is often seen to cast stupid

glances here and there, _to change her place, and walk spontaneously_.

If put into a cage, _she tries to escape_; but she comes and goes

without any purpose, or rational design. When either foot, wing,

or head is pinched, she withdraws it; when she is laid hold of, she

_struggles to escape, and screams_; but no sooner is she liberated than

she rests motionless. If severely irritated, she screams loudly; but

it is not only to express pain that she uses her voice, for it is by

no means rare to _hear her cackle and cluck a little spontaneously_;

that is to say, when no external irritation affects her. Her stupidity

is profound; she knows neither objects nor places, nor persons, and is

completely divested of memory in this respect: not only does she not

know how to seek or take food, she does not even know how to swallow it

when placed in her beak--it must be pushed to the throat. Nevertheless

her indocility, her movements, her agitation, attest that she _feels_

the presence of a strange body. Inasmuch as external objects excite in

her no idea, no desire, she pays no attention to them; but she is not

absolutely deprived of the power of attention, for if much irritated

her attention is awakened. She knows not how to escape an enemy, nor

how to defend herself. All her actions, in a word, are blind, without

reflexion, without knowledge.”

In this recital, the evidence both of _sensation_ and _instinct_ is

incontestable, to any unprejudiced mind. Bouillaud, in commenting

on his observations, remarks, that assuredly _all_ sensation was

not destroyed, since the sensibilities of touch and pain were very

manifest. Nor is it certain, he says, that the fowl heard nothing, saw

nothing. It is true that she stumbled against objects, and knew not how

to avoid them. She opened her eyes on awaking, looked about, and showed

a sensibility in the pupil to light; which, he thinks, is incompatible

with the absence of all sensation of sight

63. The experiments of Longet[271] seem decisive on this latter point.

Having removed the whole of the Cerebrum from a pigeon, he observed

that whenever he approached a light brusquely to its eyes, there was

contraction of the pupil, and even winking; but, what was still more

remarkable, “when I gave a rotatory motion to the candle, and at such

a distance that there could be no sensation of heat, the pigeon made

a similar movement with its head. These observations, renewed several

times in the presence of persons who were at my lectures, left no

doubt of the persistence of sensibility to light after removal of the

cerebral lobes.” We have only to think of the baby following with its

eyes the light moved before it, to understand the kind of impression

produced by the candle on the pigeon. Longet also declares that his

experiments prove the existence of sensations of sound, after removal

of the whole cerebrum.

64. Dr. Dalton, giving the results of numerous experiments he

performed, says that removal of the Cerebrum plunges the animal in

“a profound stupor, in which he is _almost_ entirely inattentive to

surrounding objects.... Occasionally the bird opens its eyes with a

vacant stare, stretches his neck, perhaps shakes his bill once or

twice, or smoothes down the feathers upon his shoulders, and then

relapses into his former apathetic condition. This state of immobility,

however, is _not_ accompanied by the loss of sight, of hearing, or of

ordinary sensibility. _All these functions remain, as well as that

of voluntary motion._ If a pistol be discharged behind the back of

the animal, he at once opens his eyes, moves his head half round, and

gives evident signs of having heard the report; but he immediately

becomes quiet again, and pays no further attention to it. Sight is also

retained, since the bird will sometimes fix its eye on a particular

object, and watch it for several seconds together.”[272]

While, therefore, Flourens concludes from his experiments that the

Cerebrum is the seat of _all_ sensation and all volition; and Bouillaud

concludes that it is most probably the seat of _none_; Dr. Dalton

concludes that the functions of the Cerebrum are restricted to those

usually classed as intellectual. “The animal,” he says, “is still

capable, after removal of the hemispheres, of receiving sensations

from external objects. But these sensations appear to make upon

him no lasting impression. He is incapable of connecting with his

perceptions any distinct succession of ideas. He hears, for example,

the report of a pistol, but he is not alarmed by it; for the sound,

although distinctly perceived, does not suggest any idea of danger or

injury. The memory is altogether destroyed, and the recollection of

sensations is not retained from one moment to another. The limbs and

muscles are still under the control of the will; but the will itself

is inactive, because apparently it lacks its usual mental stimulus and

direction.”[273]

Dr. Dalton reminds us how disturbance of the cerebral functions in

human beings recalls these observations on animals. “In cases of

impending apoplexy, or of softening of the cerebral substance, among

the earliest and most common phenomena is a loss or impairment of

the memory. The patient forgets the names of particular objects, or

particular persons; or he is unable to calculate numbers with his usual

facility. His mental derangement is often shown in the undue estimate

which he forms of passing events. He is no longer able to appreciate

the true relation between different objects and different phenomena.

Thus he will show an exaggerated degree of solicitude about a trivial

occurrence, and will pay no attention to other matters of importance.

As the difficulty increases, he becomes careless of the directions and

advice of his attendants, and must be watched and managed like a child

or an imbecile. After a certain period he no longer appreciates the

lapse of time, and even loses the distinction between day and night.

Finally, when the injury to the hemispheres is complete, the senses may

still remain active and impressible, while the patient is completely

deprived of intelligence and judgment.”[274]

65. Having seen how far other experimenters are from confirming the

conclusions of Flourens, let us glance at his record of observations,

and we shall find there evidence that _all_ sensation and _all_

volition cannot be localized in the Cerebrum. Speaking of a fowl whose

Cerebrum was removed the day before, he says: “She shakes her head

and feathers, sometimes even she cleans and sharpens them with her

beak; sometimes she changes the leg on which she sleeps, for, like

other birds, she sleeps habitually resting upon one leg. In all these

cases she seems like a man asleep, who, without quite waking, changes

his place, and reposes in another, from the _fatigue_ occasioned by

the previous posture: he selects one more _comfortable_, stretches

himself, yawns, shakes himself a little, and falls asleep again.... On

the third day the fowl is no longer so calm; she comes and goes, but

without motive and without an aim; and if she encounters an obstacle

on her path, she knows not how to avoid it.”[275] In his second work

he remarks of a Duck operated on in the same way: “As I mentioned last

year _à propos_ of fowls, the duck walks about oftener, and for a

longer time together, when it is fasting, than when it is fed.”

Here he observes the unmistakable evidence of feelings of Hunger,

Fatigue, and Discomfort in animals which, according to him, have lost

_all_ sensation. He also observes the operation of instinct (cleaning

the feathers), and of spontaneous activity (walking about), in animals

said to have lost _all_ instinct and _all_ volition.

66. Still more decisive are the observations recorded by other

experimenters. Leyden removed the hemispheres _and_ the ganglia at

their base from a hen; yet this hen moved about and clucked. Meissner

noticed that a pigeon whose hemispheres had been removed always uttered

its _coo_, and showed restlessness at the usual feeding-time.[276]

Voit carefully extirpated the cerebrum from some pigeons, and kept

them for many months in health. For the first few weeks they exhibited

the well-known stupor. Then they began to shake this off, open their

eyes, walk, and fly about _spontaneously_. They gave unmistakable

signs of seeing and hearing. But the chief defect was in the inability

to feed themselves, and the complete insensibility to danger. They

also manifested signs of sexual feeling with lively cooings; though

quite unable to gratify their desires.[277] Vulpian having removed

the cerebrum, optic thalami, and corpora striata from a young rabbit,

found that on pinching its tail it cried out and struggled to

escape; and a rat thus mutilated not only struggled and cried when

pinched, but manifested strong emotion. “Il est très craintif, très

impressionable; il bondit pour peu qu’on le touche; le moindre bruit le

fait tressaillir. Un certain bruit d’appel fait avec les lèvres, ou un

soufflet brusque imitant celui qu’emettent les chats en colère excitent

chez le rat une vive émotion.”[278]

67. There are several well-authenticated cases on record of children

born without a vestige of brain, and others with only a vestige, who

nevertheless manifested the ordinary signs of sensation. I will cite

but one, and it shall be one for which an illustrious physiologist,

Panizza, is the guarantee. A male infant, one of twins, who lived but

eighteen hours, during that period manifested such unquestionable signs

of Sensibility as the following: the pupils contracted under light,

sharp sounds caused flutterings, and a bitter solution when placed in

the mouth was instantly rejected. This infant had not a vestige of

cerebrum, cerebellum, or cerebral ganglia. The medulla oblongata was

normal. There were no olfactory nerves, and the optic nerves terminated

in a little mass of membrane.[279]

68. The observations of Lussana and Lemoigne are both extensive and

precise, and the conclusion at which they arrive is that the removal

of the Cerebrum is the abolition of Intelligence and Instinct, but is

not the abolition of Sensation. Whereas Rolando, and after him Renzi,

consider that only the Intelligence is abolished, the supposed loss

of Instinct being really nothing more than the loss of the directive

influence which makes the Instinct to be executed.

69. Here it becomes needful to understand

THE MECHANISM OF INSTINCT.

Were we dealing with an ordinary mechanism, and the disturbances

produced in its actions by the removal of any part, we should attribute

all observed effects to _interference with the conditions of dependent

sequence_: we should infer that the actions were imperfectly performed,

or wholly abolished, because their requisite mechanical conditions were

disturbed. Let us be equally precise in dealing with the physiological

mechanism. If we have deprived it of an organ in which certain

combinations are effected, we must expect to find all actions which

were dependent on such combinations to be now impossible; but all the

actions which are not directly dependent on these combinations may

still be possible. The actions of feeding, for example, are determined

by certain sensations, when these are present in a particular sequence,

but not otherwise; the sensation of sight does not suffice, because

the animal must not only _see_ the food, he must _perceive_ it. The

action of defence and flight are also determined by certain sensations,

but only when these are connected in a certain sequence: the brainless

animal will defend itself, or move out of the way, under the stimulus

of unpleasant sensation; but will not be moved by a _prospective_

injury, because he fails to associate it with the sight of the

threatening object. In the same way a blind man shrinks at the actual

contact of the heated poker, but does not shrink at the approach of

that poker which he does not see. We do not deny him the possession

of the so-called instinct of Self-preservation on this ground; why

deny it to the brainless animal? The brainless fish or frog swims when

placed in the water, because the sensation from the _moving_ water[280]

sets going the swimming mechanism. To call this a “swimming instinct”

may seem extravagant; yet it is as fully entitled to the name as

Self-defence is, or the Alimentary Instinct. In all three cases there

is a connate mechanism set going by appropriate feelings.

70. Since all admit that there is an Alimentary Instinct, let us see

what kind of mechanism it implies. There must be a state of feeling

called Hunger, which--combined with other feelings--determines certain

muscular adjustments in the search, recognition, capture, and finally

the swallowing of the food:--a very complex series of actions, which

lead to and sustain one another until the desire is gratified. On the

mental side there are three constituents, all indispensable: the

hunger must be felt, the food must be discriminated, the desire must

be gratified; on the physical side there are also the indispensable

arrangements of the motor mechanism. Now it is obvious that the

_entire_ mechanism of this instinct cannot be localized in the brain,

even if its mental elements are localized there; and there is reason

to believe that even the mental elements--the feelings of hunger,

discrimination, and gratification--are not exclusively localized there.

The brainless animal manifests if not the feeling of Hunger, at any

rate that feeling of discomfort which is the basis of Hunger. The

restlessness is that of a hungry animal. Now we know that some of the

Systemic Sensibility is preserved, for we see the animal breathing,

swallowing, urinating, sleeping, preening its feathers, changing its

attitude, resting on one leg after the fatigue of the other, etc. We

may therefore infer that other systemic sensations, such as Hunger and

Thirst, arise under the usual conditions.

71. We have noted an indication of Hunger; but on further observation

we discover that although the food is eaten, if brought within reach

of that portion of the feeding mechanism which is still intact, yet

the second step--the feeling of recognition--is wanting. The animal

fails to perceive the food brought under his eyes, or even placed in

his mouth; unless the back part of the mouth be touched, no swallowing

takes place. Hence the animal can no longer feed himself, and is

therefore said to have lost his instinct. But although the mechanism

of the instinct has been _disturbed_, its action is not wholly

abolished. The brain is necessary for that combination of adjustments

which normally accompany the perception of food through sight and

scent; and its absence of course frustrates such combination; but we

shall presently see that although certain sensible marks by which a

perception is guided are absent, others may still be present, and

suffice.

72. Before adducing examples let me say that we cannot legitimately

attribute the abeyance of an instinct solely to the absence of the

brain, 1°, because we observe a similar abeyance of the instinct and

frustration of perception, even when the brain is present, and the

animal is in its normal state. 2°. On the other hand, some instincts

are unmistakably manifested, and some perceptions excited, after the

brain has been removed. In fact, all that is needful is that some of

the mental elements of such perception and such instinct be preserved;

and this is the case so long as the leading element is present.

73. On the first point consider this unequivocal example. A healthy,

hungry frog may be placed in a vessel in which lie a quantity of dead

flies. He sees these flies, but sight is not enough; to him they are

only so many black spots, in which he does not recognize his food,

because the flies do not move, and the _leading element_ in his

perception of food is not a _colored_ form, but a _moving_ form. Hence

this frog, in spite of brain and an intact organism, will starve amidst

appropriate food. Whereas the frog that will not snap at motionless

flies snaps at any other small moving object, though it be not his

food. Goltz observed one incessantly snapping at the moving tentacles

of a slug which was in the vessel--as if that were possible food! Not

only the stupid frog, but the more intelligent carnivora will starve

in the presence of appropriate food which is unrecognized, because the

leading element in the recognition is absent. The cat will not eat a

dead mouse, unless she has killed it herself. Predatory animals must

capture their food--unless the scent of blood excites their alimentary

instinct. So intimately is this sensation of a moving object connected

with the predatory impulse, that the cat which is unexcited by the dead

mouse cannot resist springing on a moving ball. We need not suppose the

cat to mistake this ball for food; but we must suppose that, accustomed

to pounce upon moving food, it is unable to resist the impulse of this

leading sensation.

74. The _presence_ of the brain not sufficing, in the absence of the

leading sensation, we shall now see that the _absence_ of the brain

will not prevent the execution of the instinctive action, if the

leading sensation be present. The brainless bird sees a heap of grain,

or a pan of water, but no more recognizes them by sight alone than the

frog recognizes the dead flies; yet if the bird’s feet be placed in

the water, _this_ sensation will suffice to make him drink; if placed

amid the grain, this sensation will (sometimes) suffice to make him

feed. Lussana and Lemoigne state that their brainless pigeons ate and

drank with avidity when their feet were placed in grain and water.[281]

M. Krishaber removed the hemispheres from a pigeon, and observed that

when his beak was thrust into a heap of hempseed the head was quickly

withdrawn, whereas when the beak was plunged into water the bird drank

eagerly. Every day he was forced to feed the bird by pouring the seed

into its throat, but every day it drank when the beak was thrust into

the pan of water.[282] Brücke noticed that his brainless hen, which

made no attempt to peck at the grain under her very eyes, began pecking

if the grain were thrown on the ground with force, so as to produce a

rattling sound. The sensation of hearing was here more perfect than

that of vision, and sufficed to awaken the state of feeling necessary

to initiate the pecking movement.[283]

75. Somewhat analogous phenomena are observed in Aphasia. The patient

can see printed or written letters, and even copy them; but he cannot

read, i. e. interpret, these symbols; as the birds see the grain, but

cannot connect this sensation with others. These letters and words,

which the patient cannot interpret when _seen_, he can interpret when

_heard_; he can not only understand them when spoken, but write them

if they are dictated to him. The birds recognize the grain and water

(or act as if they did) when other sensations than those of sight

are excited. Sound is the leading element in Language, both spoken

and written. We hear the words even when we see them, but we do not

see them when we hear them. The visible symbols are accessory and

subordinate. But to the born deaf the visible symbols dominate. How one

sensation will determine a particular group of movements which cannot

be effected by any other stimulus is abundantly illustrated in disease

no less than in experiment. Here is a very luminous example: Gratiolet

had a patient for six months under his eye incapable of articulating a

single word, owing to the incoherence of her incessant utterance--she

babbled sounds, but could not group the syllables into a recognizable

word. Yet she could sing the words of any song she knew, the musical

sensations being sufficient to guide her vocal organs. “Ainsi la

mémoire, infidèle dans le cas où les mots étaient des idées, devenait

claire et précise quand les mots étaient des chansons.”[284]

76. These illustrations plainly tell how the brainless animal may

starve amid his food, failing to perceive it because the leading

sensation is not excited; and how the same animal may manifest his

feeding instinct if the mechanism be set going by a leading sensation.

We are told, indeed, that in the absence of the brain the actions are

mechanical reflexes from impressions, and not comparable with the

complex processes determined by perception. I think, however, that the

only difference is in degree of complexity: a combination of touch,

temperature, and muscular movement will be simpler than one which also

combines sight, smell, and the revived images of associated sensations.

The sight of a sheep affects the instinctive mechanism of a wolf _only_

when combined with the leading element of smell. Place a stuffed sheep

in a field, and no wolf will approach and spring on it, whereas the

blind wolf will find and capture the real sheep; and I believe that

were it practicable to remove the brain without injury to the organ of

scent and the powers of locomotion, the wolf would track and capture

the living sheep.

77. The outcome of this discussion is that the mechanism of each

instinct is the adjustment of the organs which effect the instinctive

action; and this adjustment is not simply a cerebral process, but

a complex of _many_ sensorial processes; consequently the instinct

cannot be exclusively localized in the brain, although the cerebral

process may be a very important element in the adjustment. This is

true even on the supposition that in speaking of Instinct we refer

only to the state of feeling which originates the action--separating

the psychological from the physiological aspect of the phenomenon. For

the brain _minus_ the organism is obviously incapable of feelings;

whereas the organism _minus_ the brain is obviously capable of

sensibilities adequate to determine the actions. Thus the feeling

of hunger which prompts the alimentary actions does not arise if

the animal is satiated, nor does the sexual feeling which prompts

generative actions arise when the animal is castrated; but each arises

when the organism is in a particular state. In vain will food be placed

before the satiated animal, or a female before the castrated male;

food and female are seen and recognized, but no desires are excited,

in spite of the brain and its supposed instincts. On the contrary,

when the brain is removed, the need of the organism for food is felt,

and this need determines restless movements, which are directed by

certain other sensations, and the instinctive action of feeding is

finally effected; although, of course, the removal of the brain has

so disturbed the normal mechanism of the instinct that the action is

imperfect. Renzi says that an animal deprived of its brain has lost

the intelligence which enables it to seek and seize its food, but not

the instinct, since it still has the desire for food. The following

experiment may illustrate this. Renzi wounded superficially one optic

thalamus of a frog without injuring the external margin, or optic

tract. The frog showed no appreciable loss of sight, but hopped timidly

away whenever approached. Then both thalami were divided transversely,

the optic tract still being spared. This frog remained motionless

under every threat. It manifested no alarm, and even when directly

irritated, only crawled or hopped away like a brainless frog. Sight

still so far remained that obstacles were avoided.[285] Now since this

animal’s brain was intact, and its organs of movement were capable

of responding to stimulation, how are we to explain the loss of its

instinct of self-preservation? The frog perceived no danger in a

threatening approach, yet perceived an obstacle and avoided it, getting

under it if there were room enough, crawling beside it if that was

the easier escape. Why did one vision prompt the movements of escape,

and another fail? Was it not that in the one case the normal pathway

was still open, in the other closed? We know that one injury will

destroy the perception of color without destroying that of light and

shadow; so one injury may destroy the combination of neural processes

necessary for the perception of a _danger_, without destroying those

necessary for the perception of a _hindrance_. If all actions depend

on their mechanical conditions, they must be disturbed according to

the disturbance of the conditions. Nothnagel found that after removing

the _nucleus lentiformis_ on both sides of a rabbit, leaving all the

rest of the encephalon intact, the rabbit hopped when its tail was

pinched; yet although starting at the sound when hands were loudly

clapped, did not hop as a normal rabbit does; nor although closing his

eyes when a light was brought near them, did he ever move aside. No

feeling of danger was excited by sound or sight. In striking contrast

are the phenomena manifested by a rabbit whose _corpora striata_ have

been removed: it is with difficulty made to hop by pinching its skin,

whereas noises and sights cause it to make terrified bounds.[286]

78. No sooner do we analyze the conditions of an instinct than we

see the error of regarding instincts as localized in the brain. The

cerebral process is only one factor in the product--an important

factor, no doubt, since the cerebrum is the supreme centre of

incitation and regulation; but its absence does not wholly carry

away the activity of the mechanism, sentient and motor, on which the

instincts depend, it only carries away one source of stimulation and

regulation.

79. An instinct depends on a connate mechanism. Let us glance for a

moment at a parallel case of an ordinary reflex action, also dependent

on a connate mechanism, say that of sneezing. When the inner surface

of the nose is stimulated by snuff, or other irritant, the nasal

branch of the trigeminus is excited, and the effects are first a deep

inspiration, then a closure of the respiratory orifices by the tongue,

which in turn excites a spasmodic expiration. But the same effects

are producible from quite different stimulations--namely, that of the

ciliary nerves on sudden exposure to a glare of sunshine--or of the

skin nerves on a sudden draught of cold air. Brücke remarks that there

is perhaps no spot on the surface of the body from which this reflex

may not be excited in very sensitive people. He knew a gentleman who

always sneezed when in winter he laid hold of a cold door-bell; and the

fit of sneezing was only arrested by giving him a crust of bread or

something hard to gnaw. Now just as the connate mechanism of sneezing

may be set in action by a variety of stimulations, so may the connate

mechanism of an instinct.

ACQUISITION.

80. Not only may Discrimination and Instinct be manifested in the

absence of the brain, but even the acquisition of new modes of

reaction, such as are classed under Learning through Experience.

The objection is sometimes urged that animals without their brains

only manifest single reactions on stimulation--the pinched foot

is withdrawn, and then remains motionless until again pinched.

But although the stimulation does not excite a consecutive series

of movements, because there is no cerebrum to react in successive

stimulation, this does not prove the absence of sensation in the one

movement which is excited. If my hand be lying on the table, and

something irritates it, my hand is withdrawn, and then remains as

motionless as the limb of the brainless animal, _until_ some fresh

stimulation, external or internal, moves it. Although removal of

the brain causes a manifest reduction in the variety and succession

of the movements, all experimenters are agreed that animals acquire

a certain dexterity in executing actions which they had previously

failed to carry out after removal of their brains. “There is,” says

Freusberg, “a decided improvement acquired in the reactions of the

motor centres after division of the spinal cord, not indeed in vigor,

but in delicacy. Removed from the regulating influence of the brain,

the legs acquired through practice a power of self-regulation.” Nor

is this wonderful: pathways are made easy by repetition of impulses,

and new adaptations form new adjustments. It is thus all learning is

effected--intelligent, and automatic. Nor is there any force in the

objection that the power thus acquired speedily disappears, so that if

the stimulations are effected at long intervals the reactions do not

manifest their acquired dexterity. The spinal centres forget, as the

cerebral centres forget; but they also remember, i. e. they learn.

Because an animal shows to-day none of the aptitude it acquired three

days ago, we are not to deny that it had once acquired the aptitude it

has now lost. Attempt to teach a child to read by giving it spelling

lessons of two or three minutes at intervals of two or three months,

and little will the acquisition be!

* * * * *

81. Hitherto we have been considering phenomena manifested in the

absence of the cerebral hemispheres, because it is in these that the

majority of writers place the sensorium. There are, indeed, many

authoritative writers who regard the ganglionic masses at the base of

the cerebrum, and even those of the medulla oblongata, as participating

in this sensorial property, which they refuse to the lower ganglia in

the spinal cord. I cannot follow their logic. The cerebrum is by its

position as a centre of centres, and its detachment from all direct

innervation of organs, so different from the rest of the neural axis,

that we can understand how it should be assigned a special function;

although being of the same tissue as the other ganglionic masses, it

must have the same property. And what that special function is I shall

hereafter endeavor to set forth. But that the upper region of the

spinal axis should differ so profoundly from the lower region as to

be the seat of psychical processes, while the lower region is simply

the seat of mechanical processes, is what I cannot understand, so

long as the anatomical structure and physiological properties of the

two regions are seen to be identical. The various centres innervate

various organs, and have consequently various functions. As each centre

is removed, we observe a corresponding loss of function--the organism

is truncated, but continues to manifest such functions as have still

their mechanisms intact. Let us suppose the brain or upper regions of

the cord detached from the lower regions by a section of the cord; the

animal will still live, and perform almost all its functions in the

normal way, but there will be little or no consensus between the lower

and the upper regions. Granting Sensibility to both, we must still see

that the sensation excited in one will not be felt in the other. And

this is the ground on which physiologists deny that the lower regions

have Sensibility. Without pausing here to examine this point, which

will occupy us in the next chapter, I assume that the positive evidence

of Sensibility suffices to discredit that argument; and in furtherance

of that assumption will cite an example of sensation and volition

manifested by the lower portion of the cord when separated from the

brain and upper portion.

82. The function of Urination is one which notoriously belongs to

the voluntary class, in so far as it is initiated or arrested by a

voluntary impulse, and it is one which, according to the classic

teaching, has its centre in the brain. The grounds on which this

cerebral centre is assigned are very similar to those on which other

functions are assigned to cerebral centres, namely, observation of the

suppression of the function when the pathway between certain organs and

the brain is interrupted. But the careful experiments of Goltz[287]

have demonstrated that the “centre” of Urination is not in the brain,

but in the lower region of the cord. When the cord is completely

divided, Urination is performed in the _normal_ way--not passively,

not irregularly, but with all the characters of the active regular

function. And, what is also noticeable, this function is so intimately

dependent on Sensibility that it will be arrested--like any other

function--by a sensation excited from the periphery--to be resumed when

the irritation ceases. Now this arrest from a stimulation of sensory

nerves takes place when the brain is cut off from the spinal centre,

just as when the brain is in connection with it.

The same is true of Defecation, and the still more complex functions

of Generation and Parturition. I can only refer the reader to the

very remarkable case of Goltz’s bitch with the spinal cord divided

in the lumbar region, if evidence be wanted for the performance of

complex functions so long as the spinal centres were intact. It is

true that Goltz considers these functions to have been independent

of _sensation_; but that is because he has not entirely emancipated

himself from the traditional views; for my purpose it is enough that he

admits the functions to be dependent on sensorial processes.

* * * * *

83. To sum up the evidence, we may say that observation discloses a

surprising resemblance in the manifestations of the cord and brain. In

both there are reflex processes, and processes of arrest; in both there

are actions referable to conscious and unconscious processes; in both

depression and exaltation are produced by the same drugs; in both there

are manifestations interpretable, as those of Discrimination, Logic,

Instinct, Volition, Acquisition, Memory; in both there is manifestation

of Sensibility--how then can we deny Sensation to the one if we accord

it to the other?

CHAPTER IV.

NEGATIVE INDUCTIONS.

84. I fancy some reader exclaiming: “All your reasoning, and all your

marshalled facts, are swept away by the irresistible evidence of human

patients with injured spinal cords, whose legs have manifested reflex

actions, and who nevertheless declared they had _no sensation whatever_

in them. We can never be sure of what passes in an animal; but man can

tell us whether he feels an impression, or does not feel it; and since

he tells us that he does not feel it, _cannot_, however he may _try_,

we conclude that reflex action may take place without sensation.”

As this is the one solitary fact which is held to negative the mass of

evidence, anatomical and physiological, in favor of the Sensibility of

the spinal cord, it is necessary that we should candidly examine it.

No reader will suppose that during the twenty years in which I have

advocated the doctrine expounded in this volume, I have not been fully

alive to the one fact which prevented the general acceptance of the

doctrine. From the first it has seemed to me that the fact has been

misinterpreted.

85. Certain injuries to the spinal cord destroy the connection of

the parts below the injury with the parts above it; consequently no

impression made on the limbs below the injured spot is transmitted

to the brain, nor can any cerebral incitation reach those limbs. The

patient has lost all consciousness of these limbs, and all control

over them. Hunter’s patient on being asked if he felt any pain when the

prick caused his leg to kick, answered, “No: but you see my leg does.”

This answer has been regarded as a drollery; I think it expressed

a physiological truth. For on the assumption that the whole of the

cerebro-spinal axis had one uniform _property_, corresponding with

its uniform structure, and various _functions_, corresponding with

the variety of organs it innervates, a division of this axis would

necessarily create two independent seats of Sensibility, and interrupt

the consensus of their functions. In such a case it would be absurd to

expect that the cerebral segment could be affected by, or co-operate

with, what affected the spinal segment.

Now, when a man has a diseased spinal cord, the seat of injury causes,

for the time at least, a division of the whole group of centres into

two independent groups. For all purposes of sensation and volition it

is the same as if he were cut in half; his nervous mechanism _is_ cut

in half. How then can any cerebral control be obeyed by his legs; how

can any impression on his legs be felt by his cerebrum? As well might

we expect the man whose arm has been amputated, to feel the incisions

of the scalpel, when that limb is conveyed to the dissecting-table, as

to feel by his brain impressions made upon parts wholly divorced from

organic connection with the brain.

86. But, it may be objected, this is the very point urged. The man

himself does not feel the impressions on his legs when his spine has

been injured; he is as insensible to them as to the dissection of his

amputated arm. Very true. _He_ does not feel it. But if the amputated

arm were to strike the anatomist who began its dissection, if its

fingers were to grasp the scalpel, and push it away, or with the thumb

to rub off the acid irritating one of the fingers, I do not see how

we could refuse to admit that the _arm_ felt although the _man_ did

not. And this is the case with the extremities of a man whose spine is

injured. _They_ manifest every indication of sensibility. In the frog

and pigeon the legs manifest the unmistakable control which we ascribe

to volition. It is true that the man himself, when interrogated,

declares that he feels nothing; the cerebral segment has attached to

it organs of speech and expressive features, by which _its_ sensations

can be communicated to others; whereas the spinal segment has _no_ such

means of communicating _its_ sensations; but those which it _has_, it

_employs_. You can ask the cerebral segment a question, which can be

heard, understood, and answered; this is not the case with the spinal

segment: yet if you _test_ its sensibility, the result is unequivocal.

You cannot ask an animal whether it feels, but you can test its

sensibility, and that test suffices.

87. The question we have to decide, therefore, is not whether a

patient, with an injured spine, can feel impressions on, or convey

voluntary impulses to, limbs below the seat of injury--for as respects

the nervous mechanism these limbs are separated from him, no less

than if actual amputation had taken place--the question is, whether

these separated limbs have any sensibility? And the answer seems to

me unequivocally affirmative. I assert, therefore, that if there is

ample evidence to show that the spinal centres have sensibility, when

separated from the cerebral centres, such evidence can in no respect be

weakened by the fact that a man with an injured spine is unconscious

of impressions made below the seat of injury; since such a fact

necessarily follows from the establishment of two centres: the parts

above are then not sensitive to impressions on the parts below; nor are

the parts below sensitive to impressions on the parts above; but each

segment is sensitive to its own affections.

88. Every one knows that there are animals, low down in the scale,

which may be cut in two, each half continuing to live, and each capable

of reproducing its lost segments. Would any one, seeing these separated

halves move and manifest ordinary signs of sensibility, venture to say

that the one half was a living, the other an insentient, mechanism?

And since the one half had eyes, mouth, tentacles, etc., while the

other half had none of these, would the observer be surprised that

the functions of the one differed from those of the other in these

respects? Why, then, should he not conclude the same of the two halves

of the human mechanism, when disease had divided them?

89. The man, you urge, does not feel the prick on his leg. This is

true, because “the man” here designates the seeing, hearing, tasting,

smelling, talking, thinking group of organs--to the exclusion of the

limb or limbs which are no longer in sensitive connection with this

group. When a leg is amputated “the man” remains--a truncated man,

indeed, yet still one having all the distinguishing human characters.

Yet obviously in strict language we can no longer say that the man is

the _same_ as he was. “Man” or “animal” means the complex whole; and

each anatomically separable part forms one constituent of that whole.

The medulla oblongata and spinal cord innervate certain parts; the

mesencephalon innervates others; the cerebrum rises above the whole.

If after removing one limb, then another, we continued truncating the

organism till we left only the head, should we call _that_ the man?

Clearly not. Should we even suppose that the intact brain--the supposed

seat of sensation and volition--still felt, and willed? Clearly not.

There is absolutely no evidence, however faint, of the isolated head

manifesting any sensational and volitional phenomena; whereas there

is ample evidence of the truncated spinal cord manifesting some of

these phenomena. And this is intelligible when we understand that the

nerve-centres stimulate into action the organs they innervate, but do

not by themselves play any other part.

90. “The man” then does not feel the prick on his leg, but his leg

feels it. The man has no consciousness of what takes place outside the

sphere of his sensitive mechanism; and the leg is now outside that

sphere. Consciousness--as distinguished from Sentience in general--we

have seen to be a resultant of the composition of forces co-operating

at the moment; the Sensibility of the spinal cord in the regions below

the injury cannot _now_ enter into that composition. It is detached

from the upper organs. But inasmuch as the organs it innervates are

still living and active, the functions of this detached portion are

still displayed. We have seen the dog with divided cord capable of

Urination, Defecation, Generation, etc.; its hinder legs, though not

moving in a consensus with the forelegs, yet moved independently; and

all the normal reflexes of the parts followed on stimulations. To say

that “the dog” showed no signs of Sensibility when its hinder limbs

were irritated, is identifying “the dog” with the anterior half of the

organism which was not in connection with the posterior half. It is

equally true that the posterior half showed no signs of Sensibility

when the anterior was irritated. The two halves were united by the

circulation, nutrition, etc., but disunited as to sensation and

volition.

91. Do I then suppose the separated half of an animal to feel pain and

pleasure, hope and terror? The reader who has attentively followed

the exposition will be at no loss to answer. Pain, pleasure, hope,

and terror, are special modes of Sensibility, dependent on particular

neural combinations. The organs comprised in the anterior half of the

animal furnish the main conditions for these special modes, whereas

the organs comprised in the posterior half furnish few or none of

those--they contain none of the special Senses, and they are without

the chief combining centre, the brain. But since we know that a large

amount of normal Sensation is wholly without the special characters

of pain, pleasure, hope, or terror, we need not hesitate to assign

Sensation to the spinal cord because these characters are absent.

92. All I contend for is that the spinal centres have Sensibility

of the same _order_ as the cerebral centres; and that in the normal

organism this Sensibility enters as a factor into the general

Consciousness--no one portion of the nervous system being really

independent of all the others, all co-operating in every result. Over

and over again I have had to insist that the property of Sensibility

is only the general condition of Sensation; and that each particular

sensation receives its _character_ from the organs innervated, _plus_

the reaction of the whole organism. Obviously, therefore, the peculiar

character of a sensation, or “state of consciousness,” must vary with

the variations in either of these factors. To say that every segment of

the spinal cord has Sensibility, is not saying that an excitation of

that segment will produce a particular sensation of definite character;

because for this definite character there is needed the co-operation of

all those parts of the mechanism which enter into the complex product.

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