HISTORY OF BACTERIOLOGY. 
5 
2 . The bacteria should be isolated in pure culture 
from the infected tissue. 
3 . The same pathological condition should be re¬ 
produced by inoculating animals with the bacteria. 
4 . The same bacteria should be recovered from 
the inoculated animal. 
With improved methods and appliances the rela¬ 
tionship of germs to specific diseases could be proven 
experimentally, and the discovery of the germs of 
many diseases followed with great rapidity. Since 
1879 the germs causing the following diseases have 
been discovered: Diphtheria, Leprosy, Typhoid Fever, 
Tuberculosis, Tetanus (Lockjaw), Influenza, Bubonic 
Plague, Cholera, Meningitis, Pneumonia, Syphilis, 
Gonorrhea, and others. 
The study of th^ life history or biology of these 
germs has led to our present knowledge of the cause, 
the course, and ways of preventing most of the infec¬ 
tious diseases, and has put into the hands of physicians 
the means whereby the character of an infectious dis¬ 
ease may be detected. 
From this brief sketch it is easy to appreciate 
that bacteriology is, comparatively speaking, a new 
science, and that its greatest progress has occurred 
in our time. It is advancing now even more rapidly 
than ever before along lines destined to be of the 
greatest service to humanity. Efforts are being di¬ 
rected particularly to the discovery of antitoxins and 
serums that will protect against the infectious dis¬ 
eases. 
