136 RELATIONS OF BACTERIA TO DISEASE. 



the glands of the alimentary canal, of the salivary glands, 

 may be disturbed or practically stopped, a striking analogy 

 to what is found in the action of various drugs. 



These tissue changes and symptoms are given only as 

 illustrative examples, and the list might easily be greatly 

 amplified. The important fact, however, is that nearly all, 

 if not quite all, the changes found throughout the organs 

 (without the actual presence of bacteria), and also the 

 symptoms occurring in infective diseases, can either be 

 experimentally reproduced by the injection of bacterial 

 poisons or have an analogy in the action of drugs. 



THE TOXINES PRODUCED BY BACTERIA. 



We know that bacteria are capable of giving rise to poison- 

 ous bodies within the animal body and also in artificial 

 media. As we shall see, we know comparatively little of the 

 actual nature of such bodies, and therefore we apply to 

 them, as a class the general term toxines. The fact that in 

 the case of many diseases, undoubtedly caused by bacteria, 

 the latter were not distributed throughout the body, directed 

 attention to the necessity for the existence of such toxines 

 in order to explain the general pathogenic effects occurring 

 in such circumstances. The first to systematically study 

 the production of poisonous bodies by bacteria was Brieger. 

 This observer, directing attention to general putrefactive 

 processes as they occurred under natural conditions, e.g., 

 in putrefying flesh, etc., isolated a series of crystalline 

 nitrogen-containing bodies giving the reactions of alkaloids, 

 and which he called ptomaines. Similar bodies occurring 

 in the ordinary metabolic processes of the body had pre- 

 viously been described and called leucomaines. Brieger 

 further isolated ptomaines from media containing pure 

 cultures of many of the pathogenic bacteria. These 

 ptomaines, however, on being injected into animals sus- 

 ceptible to the corresponding diseases, in no case except, 

 perhaps, in tetanus, reproduced characteristic symptoms ; 



