HISTORY OF BACTERIOLOGY. 3 



These experiments had a far-reaching influence 

 upon the conception of bacteriology, as may be imag- 

 ined, and proved beyond question that germs originate 

 only from germs. Upon this fact rest all our ideas 

 of preventing the spread of disease and the aseptic 

 precautions used in surgery. 



The association of micro-organisms with the pro- 

 duction of disease, conceived long before the organ- 

 isms were seen, received much attention after the 

 observations of von Leeuwenhoeck. During the next 

 hundred years all sorts and kinds of disease were one 

 after another attributed to the growth of germs in 

 the body. Von Plenciz (1762), a physician of 

 Vienna, was perhaps the foremost advocate of these 

 new ideas of the causation of disease. He believed 

 not only that germs gave rise to some diseases, but 

 that each disease had its own particular germ which, 

 after entering the body, developed and multiplied. 

 These theories of von Plenciz were subjected to 

 much ridicule, to be sure; but they continued to gain 

 adherents nevertheless, and have proven, as we know, 

 to be correct. Some years later Henle (1840) col- 

 lected and published all the work that had been done 

 up to that time, and pointed out that the causal 

 relationship of germs to disease could not be proven 

 simply by finding germs in the diseased tissues of 

 the body, but that they must also be grown and 

 studied outside of the body. Experiments to prove 

 the doctrines of Henle were lacking chiefly because 



