Page:Popular Science Monthly Volume 33.djvu/538

522 and cities; while the physiologist insensibly acquires the skill and erudition of the philologist.

For a long time doctors believed that they had included all the causes of disease in virulent matters, the inclemencies of the atmosphere, abuses of strength and pleasures, and indulgences of passion. The part of parasites was regarded as limited and secondary, and of those, animal parasites were regarded as the most important, while vegetable parasites were not supposed to play any appreciable part. During the former half of this century, the most intelligent persons considered botany as a part of natural history, very fit to discipline the senses and strengthen the understanding of the future doctor, to cultivate the spirit of observation within him, and to exercise him in the construction of syntheses which would permit him to classify the phenomena. The study of botany was valued only as a gymnastics of the intelligence. It was often forgotten after the first years of study, unless it was modestly called to mind to illustrate the difference between one medicinal plant and another, as parsley and hemlock, or a poisonous and edible mushroom. Now, behold the whole camp of etiologists and a good part of the camp of anatomo-pathologists pressing into the minute examination of the lowest plants, most of them belonging to the group of those microscopic fungi which are divided transversely and owe to that division an extremely rapid increase. These fungi are called, on account of the division which they undergo, schizomycetes. In many maladies, and those of the most grave, one of these species of fungus is considered the determining cause of the disease. The schizomycetes are the invisible enemies of the health of man. The chief defense against them is indirect; it consists in taking care that they do not, through hygienic deficiencies, find in the body of man a fertile soil predisposed to receive and feed them. Hence these invisible enemies have forced the doctor to interest himself in botany, if only to convince himself that the presence of a noxious fungus does not inevitably imply a sentence of death. Botany, therefore, is not only an exercise in education and an auxiliary to medicine, but it is also an integral part of medicine and a fertile source of explanations. The unity of botany and medicine is in appearance only on the ground of the infinitely little; but the economy of all organized nature is really displayed in it, the cycle of life which includes death—death from which life, the true phoenix, perpetually rises again.

Physics has higher ambitions. Mother of all the sciences, including metaphysics, and ever young in its indefatigable research, it unites the efforts of a matured experience with those of a legitimate boldness. It takes pity on the despair of the chemist who can not catch in his crucible a piece of the glowing shell of the