44 ESSAYS ON BACTERIOLOGY. 



robbed the body of important substances, to the detri- 

 ment of the host. Already it had been shown that 

 the new substances arising in the course of the fer- 

 mentations were the results of the activity of minute 

 living organisms. The yeast is put into the batter; it 

 grows, reproducing itself, spreads through the whole,, 

 produces carbonic dioxide and alcohol, and the dough 

 is inflated — made light. Here, then, is proof positive 

 that a small amount of matter may, as the result of its 

 possessing the properties of living things, spread 

 through a large mass, bringing about marked chem- 

 ical and gross physical changes, the latter being due 

 to the new chemical bodies formed in the process. 



So far as the facts were known, the analogy be- 

 tween the fermentations and the infectious diseases- 

 was exact. A small quantity of the poison of anthrax 

 being introduced into the body of an animal, or laat&f 

 in some mysterious way multiplies, spreads through 

 the body, and profoundly modifies it. This poison 

 must be a living thing. Yes, it is proven to be such, 

 and is definitely identified. May not the analogy go 

 further, so that we may say that the modifications are 

 due chiefly to new chemical substances, just as in the 

 fermentations? 



That the bacteria do, in the course and as a result 

 of their growth, bring about the formation of new 

 products, and that, in many instances, these are ex- 

 tremely poisonotis, is now- established, and this knowl- 

 edge we owe chiefly to the labors of Brieger. The 



