belief in 1863 aroused a furor of controversy.
That a microscopic vegetable could cause a virulent systemic disease
was an idea altogether too startling to be accepted in a day, and the
generality of biologists and physicians demanded more convincing proofs
than Devaine as yet was able to offer.

Naturally a host of other investigators all over the world entered the
field. Foremost among these was the German Dr. Robert Koch, who soon
corroborated all that Devaine had observed, and carried the experiments
further in the direction of the cultivation of successive generations of
the bacteria in artificial media, inoculations being made from such
pure cultures of the eighth generation, with the astonishing result that
animals thus inoculated succumbed to the disease.

Such experiments seem demonstrative, yet the world was unconvinced,
and in 1876, while the controversy was still at its height, Pasteur
was prevailed upon to take the matter in hand. The great chemist was
becoming more and more exclusively a biologist as the years passed, and
in recent years his famous studies of the silk-worm diseases, which he
proved due to bacterial infection, and of the question of spontaneous
generation, had given him unequalled resources in microscopical
technique. And so when, with the aid of his laboratory associates
Duclaux and Chamberland and Roux, he took up the mooted anthrax question
the scientific world awaited the issue with bated breath. And when, in
1877, Pasteur was ready to report on his studies of anthrax, he came
forward with such a wealth of demonstrative experiments--experiments
the rigid accuracy of which no one would for a moment think of
questioning--going to prove the bacterial origin of anthrax, that
scepticism was at last quieted for all time to come.

Henceforth no one could doubt that the contagious disease anthrax is due
exclusively to the introduction into an animal's system of a specific
germ--a microscopic plant--which develops there. And no logical mind
could have a reasonable doubt that what is proved true of one infectious
disease would some day be proved true also of other, perhaps of all,
forms of infectious maladies.

Hitherto the cause of contagion, by which certain maladies spread from
individual to individual, had been a total mystery, quite unillumined
by the vague terms "miasm," "humor," "virus," and the like cloaks of
ignorance. Here and there a prophet of science, as Schwann and Henle,
had gu