The History of the Subject 23 



contemporaries to be founded upon too little evidence, and 

 were not received. 



Plencig, of Vienna, became convinced that there was an 

 undoubted connection between the microscopic animal- 

 cules exhibited by the microscope and the origin of dis- 

 ease, and advanced this opinion as early as 1762. Unfor- 

 tunately, his opinions seem not to have been accepted by 

 others, and were soon forgotten. 



In 1704 John Colbach described "a new and secret 

 method of treating wounds by which healing took place 

 quickly, without inflammation or suppuration." 



Boehm succeeded in 1838 in demonstrating the occur- 

 rence of yeast plants in the stools of cholera, and con- 

 jectured that the process of fermentation was concerned 

 in the causation of that disease. 



In 1840 Henle considered all the evidence that had 

 been collected, and concluded that the cause of the infec- 

 tious diseases was to be sought for in minute living organ- 

 isms or fungi. He may be looked upon as the real pro- 

 pounder of the GERM THEORY OF DISEASE, for he not only 

 collected facts and expressed opinions, but also investi- 

 gated the subject ably. The requirements which he formu- 

 lated in order that the theory might be proved were so 

 severe that he was never able to attain to them with the 

 crude methods at his disposal. They were so ably elabo- 

 rated, however, that in after years they were again postulated 

 by Koch, and it is only by strict conformity with them 

 that the definite relationship between bacteria and disease 

 has been determined. 



Briefly summarized, these 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 disease. 



3. When introduced into healthy animals it must pro- 

 duce the disease, and in the animal in which the disease 

 has been experimentally ' produced the organism must be 

 found under the original conditions. 



In 1843 Dr. Oliver Wendell Holmes wrote a paper upon 

 the '' Contagiousness of Puerperal Fever." 



In 1847 Semmelweiss, of Vienna, struck by the similarity 

 between fatal wound infection with pyemia and puerperal 

 fever, cast aside the popular theory that the latter affection 

 was caused by the absorption into the blood of milk from 



