Chapter 3 CONCERNING AN STHESIA IN VIVISECTION

A few words are first of all necessary to indicate precisely what an?sthesia is.

By definition, an an?sthetic 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 an?sthetic 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 an?sthesia, 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 an?sthetics have been introduced, notably chloroform, prepared by Soubeiran in 1832, but the an?sthetic 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 an?sthetics.

An?sthetics, 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 asserting that the an?sthetised animal behaves like the an?sthetised man; that is to say, chloroform given to an animal abolishes all sensibility to pain. Vivisection, therefore, on an an?sthetised 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 an?sthetised.

If chloroform, for some reason or other, cannot be employed, many other an?sthetics, such as chloral and morphia, may be used. Chloral, in certain doses, produces complete an?sthesia, 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 an?sthetised. 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 an?sthetic as chloral or chloroform; it is therefore usual under such circumstances to administer also volatile an?sthetics like chloroform, and quite small quantities of the latter will then produce perfect an?sthesia. If, however, morphia is given in lethal doses, as is sometimes done for comparatively short experiments, it is an absolutely complete an?sthetic 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 assuring 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 substituted 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 quantity 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 an?sthesia. 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 an?sthetics, because curare is not an an?sthetic.[6]

Now, in 1894 I was able to discover a substance which has all the an?sthetic 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 an?sthesia 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 an?sthetic, and which allows the reflex actions to be studied although an?sthesia 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 an?sthesia.

For these reasons, vivisection with an?sthesia 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 passing 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 pass 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 an?sthetic, 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 an?sthetic such as chloroform or A.C.E. (alcohol, chloroform, ether) mixture is administered at the same time in sufficient amount to render an?sthesia 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 an?sthetic at all.-(W. D. H.)

* * *