XI. 



NON-BACTERIAL FACTORS IN INFEC- 

 TIOUS DISEA'SES. 



THE writer lias for some years past had much to 

 say upon the subject of bacteriology and the 

 germ theory of disease. He has also, largely by rea- 

 son of circumstances, often been called upon to act as 

 its special sponsor and defender. In so doing he has 

 always recognized, and as opportunity offered has em- 

 phasized, the danger of a one-sided view which would 

 overlook the other factors in the causation of the in- 

 fectious diseases. 



This danger, however, does not chiefly threaten 

 those whose interest in bacteriology and opportunities 

 for its study have led to a somewhat thorough knowl- 

 edge, but rather the contrary. It might, I think, 

 fairly be said that those whose interest in and study of 

 bacteriology have led to something of a reputation as 

 bacteriologists, are, for example, not as much troubled 

 over the influence of a debauch in causing the drunk- 

 ard's pneumonia as are many others over the question 

 of the role of bacteria in this disease. 



The writer has, therefore, for some time had in 

 mind to prepare a paper upon the subject announced, 



146 



