10 THE AMERICAN MONTHLY (Jan 
been determined. Briefly summarized the requirements 
are as follows: 
1. A specific micro-organism must be constantly asso- 
ciated with the disease. 
2. It must be isolated and studied apart from the dis- 
ease. 
3. When introduced into healthy animals it must pro- 
duce the disease. 
Pollender (1849) and Davaine (1850) succeeded in demon- 
strating the presence of the anthrax bacillus in the blood 
of animals suffering from and dead of that disease. Sev- 
eral years later (1863), Davaine, having made numerous 
inoculation-experiments, demonstrated that this bacillus 
was the materies morbi of the disease. The bacillus of 
anthrax was probably the first bacterium shown to be 
specific for a disease. Being a very Jarge bacillus and a 
strong vegetative organism, its growth was easily observ- 
ed, while the disease was one readily communicated to an- 
imals for experimental purposes. In 1873 Obermeier ob- 
served that actively motile flexible spiral organisms were 
present in large numbers in the blood of patients in the 
febrile stages of relapsing fever. Klebs who was one of 
the pioneers of the germ theory, published in 1872, his 
work upon septicemia and pyemia, in which he express- 
ed himself convinced that the causes of these diseases 
must come from without the body, Billroth strongly op- 
posed such an idea, asserting that fungi had no especial 
importance either in the processes of disease or in those 
of decomposition, but that, existing everywhere in the air, 
they rapidly developed in the body as soon as through 
-putrefaction a “Faulnisszymoid,” or through inflamma- 
tion a “phlogistischezymoid,” supplying the necessary 
feeding grounds, was produced. In 1875 the number of 
scientific men who had entirely abandoned the doctrine of 
spontaneous generation and embraced the germ theory of 
disease wassmal]l and most of those who accepted it were 
