year. The total number of experiments was 86,277, being 2357 less than in 1908. They were made as follows:—
| Under | Licence alone | 1,980 | |
| Under„ | Certificate C | 196 | |
| Under„ | Certificate A | 81,566 | |
| Under„ | Certificates A+E | 595 | |
| Under„ | Certificates A+F | 228 | |
| Under„ | Certificate B | 1,385 | |
| Under„ | Certificates B+EE | 319 | |
| Under„ | Certificate F | 8 |
The experiments performed under Certificate A (or A+E, or A+F) were mostly inoculations; but a few were feeding experiments, or the administration of various substances by the mouth or by inhalation, or the abstraction of blood by puncture or by simple venesection. Inoculations into deep parts, involving a preliminary incision, are required to be performed under anaesthetics (Certificate B).
“It will be seen,” says the report for 1909, “that the operative procedures in experiments performed under Certificate A, without anaesthetics, are only such as are attended by no considerable, if appreciable, pain. The certificate is, in fact, not required to cover these proceedings, but to allow of the subsequent course of the experiment.”
The animals most used for inoculations are mice, rats, guinea-pigs and rabbits. It is not once in a thousand times that a dog or a cat is used for inoculation. The act of inoculation is not in itself painful. A small area of the skin is carefully shaved and cleansed, that it may be aseptic, the hypodermic needle is sterilized and the method of hypodermic injection or of vaccination is the same as it is in medical practice. “A guinea-pig that will rest quietly in your hands before you commence to inject it, will remain perfectly quiet during the introduction of the needle under the skin; and the moment it is returned to the cage it resumes its interrupted feeding. Arteries, veins and most of the parts of the viscera are without the sense of touch. We have actual proof of this in what takes place when a horse is bled for the purpose of obtaining curative serum. With a sharp lance a cut may be made in the skin so quickly and easily that the animal does nothing more than twitch the skin-muscle of the neck, or give his head a shake, while of the further proceeding of introducing a hollow needle into the vein, the animal takes not the slightest notice. Some horses, indeed, will stand perfectly quiet during the whole operation, munching a carrot, nibbling at a wisp of hay, or playing with a button on the vest of the groom standing at its head.” These sentences, written in the Medical Magazine (June 1898) by Dr Sims Woodhead, Professor of Pathology at Cambridge, are sufficient evidence that inoculations and the like experiments are not painful at the time. In a few instances cultures of micro-organisms have been made in the anterior chamber of the eye, by the introduction of a needle behind the cornea. This might be thought painful, but cocaine renders the surface of the eye wholly insensitive. Many operations of ophthalmic surgery are done under cocaine alone, and the anterior chamber of the eye is so far insensitive that a man may have blood or pus (hypopyon) in it, and hardly be conscious of the fact. The results of inoculation are in some cases negative, in others positive; the positive results are, in the great majority of cases, not a local change, but a general infection which may end in recovery, or in death. The diseases thus induced may, in many cases, fairly be called painless—such are septicaemia in a mouse, snake-venom in a rat, and malaria in a sparrow. Rabbits affected with rabies do not suffer in the same way as dogs and some other animals, but become subject to a painless kind of paralysis. It is probable that animals kept for inoculation have, on the whole, less pain than falls to the lot of a like number of animals in a state of nature or in subjection to work: they are well fed and sheltered, and escape the rapacity of larger animals, the inevitable cruelties of sport, and the drudgery and sexual mutilation that man inflicts on the higher domestic animals.
The present writer has, of course, seen the mice that are used for the study of cancer (Imperial Cancer Research Fund), and the guinea-pigs that are used at the Lister Institute for the testing of the London milk-supply, lest the milk should convey tubercle. He did not see, among all the many animals, one that appeared to be suffering: save that a very few of the mice were incommoded, or, if the word be applicable to mice, distressed, by large tumours. Of the guinea-pigs that had been inoculated, not one seemed to be in any pain. A nodule of tubercle, or a tuberculous gland, is painless in us, and therefore cannot be painful in a guinea-pig. It is not denied that the study of some diseases (plague, tetanus) causes some pain to rats and rabbits; but this pain is hardly to be compared with the pain and horror of these diseases in man.
We come now to Certificate B. If it were lawful, under Certificate B, to make an incision under an anaesthetic, to call this the “initial operation,” and then, without, an anaesthetic, to make painful experiments, through the incision, on the deeper structures, doubtless much pain might be inflicted under this certificate. But experiments of this kind can be, and are, made under the licence alone, the animal being kept under an anaesthetic all the time, and killed under it. “No experiments requiring anything of the nature of a surgical operation, or that would cause the infliction of an appreciable amount of pain, are allowed to be performed without an anaesthetic” (Inspector's Report for 1899). “These certificates (B) are granted on condition that antiseptic precautions are used; and if these fail, and pain continues after the anaesthetics have ceased to operate, the animal is immediately killed painlessly” (Letter from the Home Secretary, 1898).
Of experiments made under this certificate (which must be linked with Certificate EE for any experiment on a dog or a cat), three instances may be given here: an operation on the brain, a removal of part or the whole of a secreting gland, and the establishment of a fistula. It is to be noted that, for these and the like operations, profound anaesthesia and the strict observance of the antiseptic method are matters of absolute necessity for the success of the experiment: the operation could not be performed without anaesthesia; and the experiment would come to nothing if the wound suppurated. It is to be noted, also, that these operations are such as are performed in surgery for the saving of life or for the relief of pain.
As to operations on the brain, it must be remembered that the surface of the brain is not sensitive. Therefore the removal or destruction of a portion of the surface of the brain, or the division of some tract of central nervous tissue, though it might entail some loss of power or of control, does not cause pain: a wound of the brain is painless. Tension within the cranial cavity, as in cases of cerebral tumour or cerebral abscess, may indeed cause great pain; and, if the aseptic method failed in an experiment, inflammation and tension would ensue: in that case the animal must be killed.
The removal of part or the whole of a secreting gland (e.g. the thyroid, the spleen, the kidney) is performed by the same methods, and with the same precautions, as in human surgery. Profound anaesthesia, and the use of a strict antiseptic procedure, are of absolute necessity. The skin over the part to be removed must be shaved and carefully cleansed for the operation; the instruments, sponges and ligatures must be sterile, not capable of infecting the wound; and when the operation is over, the wound must be carefully closed with sutures, and left to heal under a proper surgical dressing.
The establishment of a fistula, again, is an operation practised, as a matter of course, in large numbers of surgical cases. The stomach, the gall-bladder, the large intestine, are opened for the relief of obstruction, and kept open, either for a time or permanently, according to the nature of the case. Under anaesthesia, the organ that is to be opened is exposed through an incision made through the structures overlying it, and is secured in the wound by means of fine sutures. Then, when it has become adherent there, it is opened by an incision made into it; no anaesthetic is needed for this purpose, because these internal organs are so unlike the skin in sensitiveness that an incision is hardly felt: the patient may say that he “felt a prick,” or he may be wholly unconscious that anything has been done. A
