10 ESSAYS ON BACTERIOLOGY. 



an animal or man, and afterward that the body con- 

 tained a much larger quantity of the poison. They 

 saw one case of a disease enter a community, and 

 afterward they saw, with strong evidence of transfer 

 from one to another, that many others had the disease. 

 From such facts they made the same inference as we 

 do. They said: these poisons seem to grow and mul- 

 tiply; they must be living; for such properties as true 

 growth and reprodiiction they, as we, only knew as be- 

 longing to living things. And this is the germ theory 

 of disease. When we inquire why this simple and 

 logical doctrine became, at times, contaminated with 

 so much absurdity as to bring it into merited discredit 

 and to even threaten its survival, the answer is not 

 difficult to find. 



However rational, however logical, it was but a 

 theory, a mere speculation, shrouded in mystery. The 

 ignorant mind loves mystery, and all men love to 

 specidate about that which they cannot prove. We 

 all love to peer into the darkness, and where we can- 

 not see we quickly bring imagination into play. A 

 Greek proverb tells us that the mysterious is always 

 great, and imaginary greatness is easily distorted into 

 absurdity. It is as true in medicine as in theology 

 that men often make the most positive and at the 

 same time most extravagant assertions about things of 

 which they know the least. 



Thus the germ theory of disease became at times so 

 distorted, the subject of so many evidently ulnwar- 



