THIRD JOURNEY TO THE CAUCASUS. 311 



The cure was said to be effected by introducing 

 into the patient's system a poison, produced by the 

 phthisis-producing bacteria themselves, in the shape of 

 their vital products. The reported results left no 

 doubt as to the correctness of the fact, and we 

 Germans heard with pride on all sides our countryman 

 lauded as a benefactor of humanity. But the assumption 

 of Koch, that the vital products of the disease-causing 

 bacilli constitute the powerful deadly poison, even 

 then excited my doubts. One could well imagine that 

 this self-induced poisoning might check the development 

 of the bacilli in the parts of the body occupied by them 

 - thus affording an explanation of the remarkable 

 phenomenon, that not every infectious disease leads to 

 the death of the person assailed by it - - but it appeared 

 inconceivable to me that an infinitesimal quantity of 

 such poisonous vital products of a limited number of 

 bacilli should produce in another body the powerful 

 effects observed. A vital process alone could accomplish 

 this, in which not the substance of the germs intro- 

 duced, but the vital conditions maintaining them, and 

 the time required for their increase, are the chief 

 factors in the case. The question as to the origin of 

 these germs, which develop a life hostile to the 

 bacilli whence they arise, appears to me only to admit 

 of a plausible answer, if one supposes the living beings 

 producing the disease to be themselves subject to 

 infectious diseases , whereby they on their part are 

 checked in their vitality and finally killed. It would 

 of course follow that life, animal as well as vegetable^ 



