52 THE GERM THEORY OF DISEASE. 



of chicken cholera. This experimenter finds that dilutions 

 of the fluid containing these organisms first produce a mild 

 type of the disease which they induce, and finally, as the 

 dilution is increased, fail entirely to produce an effect, although 

 there may still remain in the drops injected a number of the 

 organisms. He believes the vital energies of the animal 

 resist the growth of the organisms, and that numbers are 

 required to overcome this. We will allude to this again. 



BILLROTH. 



Billroth, in the course of his inquiries in the early part of 

 the sixth decade, published in 1874, came to the conclusion 

 that organisms were present in the human body and in the 

 bodies of animals in a state of health. And he supposed 

 that in case of injury they need not be introduced from with- 

 out in order to develop in a wound and produce sepsis, but 

 that they may come from the tissues beneath, and if the con- 

 ditions of the wound be not rendered unfavorable for them, 

 they may develop sepsis. Professor Thiersch seems to have 

 attached great importance to this view. 



In the same publication, Professor Billroth held, also, the 

 view that bacteria were the accompaniments of disease, but 

 denied that they were a cause. His view of contagion seems 

 to have been divided somewhat between those of Liebig and 

 those of Beale (vide infra), that is, he seems to have regarded 

 both these as operative causes or modes of formation of con- 

 tagious matters. 



In his introduction to a report on surgery, in 1876, he takes 

 occasion to speak of this subject again, and seems to have very 

 materially modified his views, as will be seen by the following 

 sentence, which I quote: "I still hesitate to accept uncon- 

 ditionally the assurance of our best observers, that zymotic 

 germs have much to do with the causation of erysipelas, 



