When we touch the tentacles of a star-fish, we notice, near the tentacles touched, a sort of agitation set up among the neighbouring tentacles, but this agitation does not extend to the tentacles of the others' arms; so that a general consciousness does not appear to exist, unless it be in a prodigiously rudimentary state, among inferior beings. In certain cla.s.ses of the mollusca there is no head. Thus oysters and mussels, named on that account _acephala_, have in all probability no consciousness. I would have no scruple, therefore, either in eating living oysters, or in experimenting upon living oysters and mussels, since it seems to me evident that the notion of pain does not exist in them.

It is not the same thing with insects; it is here that the first signs of pain begin to appear. Nevertheless, we must be careful to avoid confusing pain with signs of pain. When we take a worm and cut it into three segments, each of these segments will struggle and writhe in a perfect frenzy. It would, therefore, be necessary to admit that pain existed in each of these three segments--in other words, that each fragment possesses a central seat of pain, which is absurd; it is much more rational to suppose that the perturbed movements of the animal are the result of a strong nervous excitation, and that the injury is accompanied by defensive reflex movements but provokes no painful perception.

Among the superior animals however, and especially among the vertebrata, pain exists. There can be no doubt about this, although it is impossible to know exactly in what consists the consciousness of pain in an animal; the most profound obscurity still reigns, and will perhaps always reign, over their consciousness and sensations. It would be ridiculous to deny that a dog suffers when his paw is crushed. Certainly, I fully believe that all pain is much less clearly perceived by the dog than by man. But, after all, it is a phenomenon of the same order and identical, save in intensity.

Now pain, taken in its profoundest sense, consists of two essential elements: a shock to the conscious self, the _ego_, in the first place; and, in the second place, the prolongation of the shock. If the self is not distinctly conscious, if it does not go so far as to a.s.sert itself by the separation of that self from the external world, we cannot say that pain is possible. The _ego_ never a.s.serts itself with so much force as under a very painful impression. So that among beings whose reactions are mechanical, automatic, governed by other forces than by the a.s.sertion of the self and a freely deliberate will, pain becomes so indistinct, so confused, that it probably does not exist in the strict psychological sense at all. The greatest philosopher of modern times, Descartes, imagined a system of machine-animals; this idea has been turned into ridicule by the ignorant, but nevertheless we are almost forced to return to it when we dive to the bottom of reflex movements. Now, if we are able to admit that there is a vague consciousness of the selfhood among superior animals, such as the mammalia and birds, this consciousness, as far as concerns the inferior vertebrata, is most certainly extremely hazy, if, indeed, it exists at all. I have difficulty in conceiving that a frog is able to ponder over its _ego_, a.s.sert its existence in presence of the external world, and say or think, I SUFFER. No being suffers unless he is able to think that he suffers, and meditate on his suffering. To suffer means to have consciousness; and as far as it is permissible for a man to picture to himself the sensations of a frog, I should say that the frog has no consciousness of suffering.

Even as regards the more highly developed vertebrata, such as birds, rabbits, and guinea-pigs, suffering is probably of a very obscure nature.

It is not enough to say that an animal suffers because we see him animated by the contortions and reactions of defence. The new-born infant, which has neither intelligence nor memory nor consciousness, is probably incapable of real conscious suffering, nevertheless it screams and cries when it is hungry or when it is p.r.i.c.ked. But these screams and tears do not suffice to allow us to affirm that the child is suffering real pain. It is a nervous excitation which is translated by the reactions of defence; it is not the conscious a.s.sertion of an _ego_ which has been painfully perturbed.

Further, for pain to exist the impression must be durable and not fugitive. The a.s.sertion of the _ego_ is not enough. It must be prolonged. A pain, however intense we may suppose it to be, which traverses the organism for a second and which leaves no painful echo behind it, is no real pain. I will allow any one to inflict the most excruciating tortures on me if he can a.s.sure me that, at the end of one second, I shall have lost all recollection of the suffering and that no trace of the torture will remain.

The extraction of a tooth lasts perhaps only half a second, but you remember it all your life. In any case, for several minutes the pain continues to be atrocious. Therefore we may certainly consider that pain is a phenomenon of memory. Pain is an empty word for every being that has no memory.

From these facts we may evolve the general conclusion that, under penalty of falling into vulgar anthromorphism, we cannot apply to the pain of animals the data which have been gathered on human pain.[5] With man, the developed intelligence and vivacious memory enable pain to acquire an extreme intensity. But with animals, in proportion as the intelligence lessens and the memory becomes more rudimentary, so does pain diminish, and, without having the right to be very affirmative, as we are in profound darkness concerning the consciousness of animals, it appears to me that, as we descend the scale of the animal kingdom, pain rapidly becomes very hazy, scarcely perceived, and as indistinct as the consciousness of the _ego_.

We have, therefore, the right to perform vivisection on beings which, because they possess no _selfhood_, do not suffer. Now, this absence of memory, consciousness, and intelligence extends a.s.suredly over the whole of the vegetable kingdom, almost certainly over all the groups of the invertebrata, and also probably over all the inferior vertebrata.

Finally, there remain only the mammalia and birds which are capable of real pain. Although this pain may be obscure and indistinct, it is certain; and we must take it into consideration or fall into barbarism; therefore we shall restrict the problem of vivisection to the vivisection of superior animals, who, alone, are capable of suffering.

FOOTNOTES:

[4] The true vegetarian is an extremely rare person. The usual so-called vegetarian ought more properly to be called a non-meat eater, for he does not scruple to consume milk (intended by nature for the calf) and milk products (cream, cheese, and b.u.t.ter) and eggs, nor to wear garments made of wool and leather.--(W. D. H.)

[5] In the little leaflet already referred to, quotation is made of a sentence from Professor Pritchard, which says that the various animals have a skin of different thickness, but that sensibility is the same among all, including man. It seems to me that Professor Pritchard has scarcely looked into the questions of general psychology.

CHAPTER III

CONCERNING ANaeSTHESIA IN VIVISECTION

A few words are first of all necessary to indicate precisely what anaesthesia is.

By definition, an anaesthetic is a substance which, without paralysing the activity of the heart and the respiration, abolishes sensibility. Indeed, whenever general sensibility is abolished, there is, at the same time, abolition of consciousness, of intelligence, and of memory. Another characteristic of an anaesthetic is that its action is of a transient nature. At the end of a certain time, it disappears; and then intelligence, consciousness, and memory return gradually with sensibility.

It is well known that the admirable discovery of general anaesthesia, allowing operations to be performed on man without the accompaniment of pain, was due to chance. It was an American dentist, Horace Wells, and his colleague, Morton (and others also perhaps), who discovered by chance that protoxide of nitrogen (commonly called laughing gas) has the power, when inhaled, of annulling all sensibility to pain for a certain length of time--sufficiently long for a surgical operation (1840). Then they discovered the effects of ether (1842). Since then, many other anaesthetics have been introduced, notably chloroform, prepared by Soubeiran in 1832, but the anaesthetic properties of which were only discovered in 1847 by Flourens and Simpson; so that physiologists and surgeons are now quite familiar with the mode of action of anaesthetics.

Anaesthetics, in appropriate doses, poison the nervous cells, which are the seat of intelligence and sensibility, but leave unimpaired the functions of the cardiac nervous system and of the nervous system governing the respiration. An individual under chloroform breathes regularly; his heart beats rhythmically, but all intelligence has disappeared; he has no longer any will or memory or reflex actions, and the most painful operations can be performed on him without provoking the smallest phenomenon of sensibility.

Further, we have no hesitation in a.s.serting that the anaesthetised animal behaves like the anaesthetised man; that is to say, chloroform given to an animal abolishes all sensibility to pain. Vivisection, therefore, on an anaesthetised animal, does not provoke any pain. Physiologists are so convinced of this that, however humane they may be, they have no scruple in performing lengthy vivisections on an animal which is thoroughly anaesthetised.

If chloroform, for some reason or other, cannot be employed, many other anaesthetics, such as chloral and morphia, may be used. Chloral, in certain doses, produces complete anaesthesia, and it is easier to administer than chloroform. Formerly, chloral was injected, by a small puncture, into the veins of rabbits and dogs. I pointed out another method which allows one to avoid even the puncture; it is sufficient to make a rectal injection of the solution of chloral. In two or three minutes, the dog, the rabbit, or the guinea-pig, is seized with a kind of inebriety; he staggers, falls to the ground, and in about ten minutes he is completely anaesthetised. Large doses of morphia can be injected into animals without causing immediate death.

An animal under a moderate dose of morphia does not absolutely lose all sensibility to pain; but the slight pain which he then feels is very transient. If the animal is submitted to strong excitation, he wakens for a few seconds, but soon falls back again into profound slumber. Morphia in moderate doses is not such a perfect anaesthetic as chloral or chloroform; it is therefore usual under such circ.u.mstances to administer also volatile anaesthetics like chloroform, and quite small quant.i.ties of the latter will then produce perfect anaesthesia. If, however, morphia is given in lethal doses, as is sometimes done for comparatively short experiments, it is an absolutely complete anaesthetic in itself, just as it is when a man takes a fatal dose of morphia, or of its parent substance, opium.

Nevertheless, chloroform, chloral, and ether have a very serious disadvantage for the physiologist. They abolish sensibility, but, at the same time, they abolish the majority of the reflex actions in which voluntary muscles are concerned. Now, in many experiments, it is indispensable to be able to study such reflex movements, that is to say, the fundamental reactions of the nervous system. Thus, physiologists, more preoccupied, it must be said, with a.s.suring the immobility than the insensibility of the animal, have had recourse to another substance, _curare_, the properties of which were investigated by Claude Bernard.

Curare is a poison which the natives on the banks of the Amazon prepare from a bind-weed of the strychnia family. They boil the plant with several ingredients, finally obtaining a sort of blackish resin, or gummy juice, which they place in little gourds, which can be procured also in Europe.

This juice is used by South American Indians for their arrows, and physiologists use it to ensure the immobility of the animal on which they are experimenting. Curare dissolves in water, and a solution of a few centigrams injected under the skin of a dog, a cat, a rabbit, will bring about the death of the animal in a few minutes. But death is not due to the arrest of the heart's action, it is due entirely to paralysis of the respiration. Therefore the curarised animal can continue to live for several hours if _artificial_ breathing be subst.i.tuted for the natural breathing which is paralysed. For several hours the animal is completely motionless; the heart beats with force and regularity, provided that the insufflation of air into the lungs introduces into the blood the quant.i.ty of oxygen necessary for the life of the tissues. Now, under these conditions, as Claude Bernard has so well demonstrated, we have no proof that sensibility is abolished also. There is immobility; there is no true anaesthesia. Take two animals, one chloroformed, the other curarised; both are equally inert; but the chloroformed animal is insensible, whilst the curarised animal retains sensibility.

It is impossible, therefore, to say that curare replaces anaesthetics, because _curare is not an anaesthetic_.[6]

Now, in 1894 I was able to discover a substance which has all the anaesthetic properties of chloroform, and which nevertheless does not abolish reflex actions, so that physiologists are able to use it for experiments which, formerly, necessitated the use of curare. This substance is called _chloralose_; it is obtained by mixing anhydrous chloral with glucose. It is not necessary for me to describe here in detail its chemical or physiological properties; I will only say that in very small doses (about twenty-five centigrams) it is an excellent hypnotic for man, and that in larger doses, injected into the vein of a dog or a rabbit, it brings about complete anaesthesia without affecting either the breathing, the heart, or the reflex actions.

Since this discovery, many physiologists--and I regret not to be able to say so of every physiologist--have given up curare and use nothing but chloralose, which is a perfect anaesthetic, and which allows the reflex actions to be studied although anaesthesia is perfect.

It may be objected that a tiny puncture has to be made in the vein to introduce the chloralose into the circulation; but this puncture is really such a trifle that it would be sheer childishness to pay any attention to it. What doctor would hesitate to make a puncture in the skin of his patient for the injection of a solution of morphia? However, if sentimentality be pushed to such a degree as to shrink from touching the vein of a dog in order to put him to sleep, even this tiny puncture can be avoided by mixing the chloralose with the food of the animal to be experimented upon. In half an hour or three-quarters of an hour after the mixture is given he is in a state of perfect anaesthesia.

For these reasons, vivisection with anaesthesia seems to me to be quite legitimate. As soon as it is recognised that man has the right to kill the animal, he has the right to kill him as he pleases, provided he spares him all suffering.

Let us also reflect a little on this point: an animal has to die just as much as we ourselves. Now, natural death would certainly be for him a long and cruel agony, lasting several hours, several days, perhaps several weeks. Well, then, we replace hideous old age, the agony of prolonged tortures due to disease, by a dreamless sleep, which at once plunges the animal into nothingness, without his pa.s.sing through the intermediary stage of necessary suffering. Is this what is called being inhuman? For my part, I shall regret on my death-bed that no physiologist will be found whose conscience will permit him, or, if so, who would have sufficient courage to help me to pa.s.s away under the influence of chloroform, ether, chloralose, morphia, or chloral, thus saving me from the throes of the final struggle, and bestowing upon me a peaceful death and an easy termination of all suffering.

FOOTNOTES:

[6] In England, the Vivisection Act expressly states that curare is not to be regarded as an anaesthetic, and this proviso has been loyally accepted by English physiologists. On those rare occasions when curare is used, and the occasions are very rare indeed, and year by year they become rarer, a volatile anaesthetic such as chloroform or A.C.E. (alcohol, chloroform, ether) mixture is administered at the same time in sufficient amount to render anaesthesia absolute. One should add that since Claude Bernard's work on curare, physiologists have seen reason for doubting whether it leaves sensibility intact, as Bernard thought. But as there is doubt on the question, and the available evidence in favour of its lulling sensations is small, it is still considered advisable to retain Bernard's views, and act as though it is not an anaesthetic at all.--(W. D. H.)

CHAPTER IV

CONCERNING EXPERIMENTATION OTHER THAN VIVISECTION

We must, however, give to the word "Vivisection" its largest acceptation.

It is not only a question of cutting nerves, of stimulating the glands, or of exciting the muscles. There are experiments of much longer duration in which there is no mutilation properly speaking, but _intoxication_,[7]

produced by the injection of poisons and disease germs.

It is, indeed, evident that pain can be provoked in other ways than by a sharp-edged instrument, which can always be done under anaesthesia. But may inoculation be performed? May prolonged _intoxication_ be caused? To treat the question in all its fulness, we will put the problem in the following manner.

In order to study a disease, have we the right to give that disease to an animal?

For my part, there can be no doubt on the point, and I affirm that such is our right.

As a matter of fact, and as every unbia.s.sed person is forced to recognise, it is only by experimentation that these diseases can be studied thoroughly. Clinical observation, bearing exclusively upon man, can only give incomplete results, much poorer, though its doc.u.ments are mult.i.tudinous, than the results furnished by experimentation, which can be infinitely varied at will. If we were limited to the Hippocratic method of observation, which consists in studying the symptoms and the progress of a morbid affliction, we should be reduced to poor enough resources; and if meditation on the aphorisms of Hippocrates const.i.tuted the whole extent of our medical science, medical science would be a sad vacuum. Fortunately, however, such is not the case. Marvellous progress has been realised, which allows us to entertain quite other ideas than those of the Father of Medicine on the nature of diseases, and consequently on their treatment and their prevention. Those very persons who rise up in arms against physiological experimentation would not, I imagine, desire to be handed over to the care of a Hippocratic doctor if they were ill, to a doctor who took no notice of any modern discoveries under the pretext that they were acquired by experimentation _in anima vili_.

If, however, we wish to discuss the problem thoroughly, it will not do to remain on indefinite ground. Let us arrive at precise facts. I will mention only three discoveries, the importance of which is considerable, and which have been established solely by experimentation.

First of all, there is _antisepsis_. For centuries and centuries surgeons operated without understanding why it was that death struck down so unmercifully those operated upon. In vain did surgeons display great skill; in vain did the operation succeed: the patient died. Erysipelas, lock-jaw, abscess-formation and gangrene reigned supreme. Every confinement exposed the mother to death; the slightest wounds were followed by the most serious after-effects; in certain amputations, for instance, the mortality was 70 per cent. No one dared to touch either the peritoneum or the joints, because every operation on the peritoneum or on the articulations was sure to prove fatal. But Lister and Pasteur came! These two men, simultaneously and concurrently, demonstrated that all disease following on an operation was the result of infection by parasites. By preventing the wounds from being contaminated by parasites, infection was prevented; for the wounds themselves are innocent, as long as they are not infected.

This is the astounding and simple truth which Lister and Pasteur established. And let no one pretend it is so simple that the data could have been furnished by clinical observation alone, for such an a.s.sertion would be contradicted by the facts.

Thousands and thousands of surgeons, right up to 1868, had understood nothing of infection. In order to understand this big word "infection,"

which sums up in itself the whole of surgery and the whole of medicine, it was necessary to inject pus into animals, gather the microbes which then developed in the blood of these animals, isolate the microbes, cultivate them, inject them afresh, and produce an experimental disease. It was in this manner only that we were able to understand the mechanism of antisepsis, and, consequently, apply it to the treatment of operations and wounds. Three or four volumes could be written on this subject alone, but all I can attempt here is a summary of the main points. I say without hesitation that as long as clinical medicine confined itself only to the observation of patients, it was able to understand nothing, to a.n.a.lyse nothing, to foresee nothing. It was necessary to experiment, to sacrifice a few hundred mice, rats, and rabbits, in order to demonstrate that erysipelas is an inoculable disease, that puerperal infection is of the same nature as purulent infection, that all these diseases are due to micro-organisms, and that certain substances, called antiseptics, can stop the development of these fatal germs.

It appears quite natural to-day (and it seems to simple minds, ignorant of the past and powerless to imagine the past, that these notions have been current from all eternity) to know that instruments, water, and linen heated to 120 contain no living germs. But this discovery is not so very old. It was Pasteur who, between 1863 and 1873, established it by some memorable experiments at the cost of a little disease given to rats and guinea-pigs.

[Ill.u.s.tration: PASTEUR IN HIS LABORATORY.