Louis Pasteur: His Life and Labours

by René Vallery-Radot

'If a pigeon be inoculated in the pectoral muscle with the microbe of swine fever, the pigeon dies in an interval of six or eight days, after having shown the apparent exterior symptoms of fowl cholera.

'When a second pigeon is inoculated with the blood of the first, a third with that of the second, and so on in succession, the microbe acclimatises itself to the pigeon. The symptoms of forming itself into a ball, and of somnolence, which are the habitual characteristics of the disease, appear in a much shorter time than with the first pigeons of the series. Death likewise comes on more rapidly. Finally, the blood of the last pigeons exhibits much more virulence in the pig than even the most infectious products of a pig that has died of what is called spontaneous fever.

'The passage of the swine fever microbe through rabbits leads to quite a different result. Rabbits inoculated with the infectious products of a pig that has died of the fever, or with the cultivations of them, are always made ill and most frequently die.

'When the virus is inoculated from rabbit to rabbit, the microbe acclimatises itself to the rabbit. All the animals die, and death comes in a very few days. The cultures of the blood of these rabbits in sterilised media become progressively easy and more abundant. The microbe itself changes its aspect somewhat, grows rather larger than in the pig, and appears in the form of an 8, without the filiform lengthening out characteristic of certain other cultures.'

'When pigs are inoculated with the blood of the last rabbits, and the results compared with those obtained from the first of the series, it is found that the virulence has been progressively diminishing from the first rabbit to the following ones. Very soon the blood of the rabbits ceases to cause death in the pigs, though it renders them ill. On recovery they are proof against the deadly swine fever.'

III.

But in the midst of these investigations undertaken by Pasteur, there is one which is paramount over all the others, one on which for three years all his efforts, as well as those of his pupils, have been concentrated, and this is Hydrophobia. Mysterious in its incubation, alarming in its symptoms, Pasteur's attention had for a long time been drawn to it, when in 1880 he finally attacked it. Besides the attraction which an obscure problem had for him, he felt that if he succeeded in discovering the probably microbean etiology of such a disease, he would carry all minds with him into the current of these new ideas. He had been very often struck, if not with the opposition, at least with the prudent and circumspect reserve, shown in the examination of his doctrine, by a considerable number of physicians who, possessed by the idea that the moral element could cause modifications in the symptoms and development of a malady in man, are not disposed to recognise the least assimilation between human diseases and those of the animal species. No doubt the emotional qualities, grave family cares, the terror of approaching death, the dread of the great unknown, may modify the course of the evil in man, may aggravate it, even hasten it; but, whilst recognising—for never was there a man more a creature of sentiment than he—what there is of deep truth in this opinion, Pasteur could not help thinking that the first origin, the cause of every contagious malady, is physiologically the same in the two groups, and that our bodies, notwithstanding our superior moral qualities, are exposed to the same dangers, to the same disorders, as the bodies of animals.

To overcome these resistances, it was necessary, as in the great experiments on splenic fever, to attack a disease common both to men and animals—one in which experimentation, the only, but great, strength of Pasteur, was supreme. Hydrophobia offered these conditions.

Again, it was Dr. Lannelongue who introduced Pasteur to his first case of hydrophobia. On December 10, 1880, a child of five years old, who had been bitten in the face a month previously, was dying in the Trousseau Hospital. Devoured at the time by a raging thirst, and seized with a horror for all liquids, he approached with his lips the spout of a closed coffee pot, then suddenly started back—the throat contracted—a prey to such fury that he insulted the nursing sister who was attending on him. He was at the same time attacked by aerophobia to a prodigious degree. At a certain moment, the heel of one of his feet protruded from the bed. An assistant blew on it. The child had not seen the assistant, and the breath of air was so light as to be almost imperceptible. The poor child flew into a rage, and a violent spasm seized him in the throat. The next day delirium began, a frightful delirium. The frothy matters which filled his throat suffocated him.