The rest of M. Chamberland's paper is concerned with the defects, such as they are, of the vaccinations, and the need of absolute cleanliness in the making of them: which is somewhat difficult for this vast number of vaccinations of animals all over France, and in other parts of the world. The whole story of the discovery is told in M. Valléry-Radot's Life of Pasteur: and the whole story of rouget, in the same most fascinating book, vol. ii., p. 180.
III
TUBERCLE
Before Laennec, tubercle had been taken for a degenerative change of the tissues, much like other forms of degeneration. It was Laennec who brought men to see that it is a disease of itself, different from anything else; and this great discovery of the specific nature of tubercle, and his invention of the stethoscope, place him almost level with Harvey. He founded the facts of tubercle, and on that foundation Villemin built. In 1865, Villemin communicated to the Académie des Sciences his discovery that tubercle is an infective disease; that he had produced it in rabbits, by inoculating them with tuberculous matter. En voici les preuves, he said. He appealed to these inoculations to prove his teaching:—
La tuberculose est une affection spécifique. Sa cause réside dans un agent inoculable. L'inoculation se fait très-bien de l'homme au lapin. La tuberculose appartient donc à la classe des maladies virulentes.
It was no new thing to say, or to guess, that phthisis was or might be infective. So far back as 1500, Frascatorius had said that phthisis came "by the gliding of the corrupt and noisome humours of the patient into the lungs of a healthy man." Surely, if clinical experience could suffice, men would have made something out of this wisdom of Frascatorius. They made nothing of it; they waited three hundred years for Villemin to inoculate the rabbits, and then the thing was done—En voici les preuves. Three years later, Chauveau produced the disease in animals, not by inoculation, but by the admixture of tuberculous matter with their food. Then, as the work grew, there came a short period of uncertainty: different species of animals are so widely different in their susceptibility to the disease that the results of further inoculations seemed to go against Villemin; and it was not till 1880 that Cohnheim finally established Villemin's teaching, and even went beyond it, making inoculation the very proof of tubercle:—
"Everything is tuberculous, that can produce tuberculous disease by inoculation in animals that are susceptible to that disease: and nothing is tuberculous, that cannot do this."
Then, in 1881, came the welcome news that Koch had discovered the bacillus of tubercle. In his first published account of it (24th March 1882) he says:—
"Henceforth, in our warfare against this fearful scourge of our race, we have to reckon not with a nameless something, but with a definite parasite, whose conditions of life are for the most part already known, and can be further studied.... Before all things, we must shut off the sources of the infection, so far as it is in the power of man to do this."[18]
In November 1890 he announced, in the Deutsche Medizinische Wochenschrift, the discovery of tuberculin. Its failure was one of the world's tragedies. The defeat may not be final, and we may live to see phthisis fought and beaten with its own weapons: but, for the present, it is more to the purpose to consider what other benefits have been gained, from the discovery of the tubercle-bacillus in 1881, in every civilised country in the world.
1. It has given to everybody a more reasonable and hopeful view of phthisis and the diseases allied to it. The older doctrine of heredity, that the child inherits the disease itself, has given way to the doctrine that the inheritance, in the vast majority of cases, is not that of the disease itself, but that of a tendency or increased susceptibility to the disease.