442 MICROBIOLOGY 



phenomena in the animal body. In the study of this subject 

 it is important to recognize and to keep clear and distinct two 

 phenomena, namely: (1) that many bacteria elaborate during 

 their multiplication either in the body or in culture media 

 poisonous substances known as toxins and (2) that these poi- 

 sons produce when in the animal body a reaction on the part 

 of the tissues which results in their (tissues) giving off certain 

 reactionary bodies or substances known as antitoxins, or anti- 

 bodies. 



The products of bacterial growth. The more important 

 of the bacterial products at least so far as they have been 

 analyzed and determined are the " bacterial proteins" and 

 toxins. 



Bacterial proteins. These substances are bacterial poi- 

 sons which are not as a rule specific. They excite fever, in- 

 flammation and suppuration and withstand heating to a tem- 

 perature of 100 C. Vaughan and Novy 3 classify the bac- 

 terial proteids as follows: (1) those which constitute an 

 integral part of the bacterial cells; and (2) those which have 

 been assimilated by the cells, but which have been formed by 

 the fermentative or cleavage action of the bacteria on the 

 proteid bodies in which they are growing. Tuberculin and 

 mallein are the most important of this group of bacterial 

 products. According to Buchner and Roemer, all bacterial 

 proteins are very similar in their action. It has been stated 

 that deuteroalbumose, which is obtained by the action of pepsin 

 on albumin and has no connection with bacteria, has an effect 

 on tuberculous guinea pigs somewhat similar to tuberculin. 



Toxins. Toxins are poisonous synthetical products of 

 bacterial growth. 



Although the exact composition of the toxin of any 

 species has not as yet been determined, it is believed that they 

 are of proteid character. At first all the toxins were supposed 

 to be albumins, but recently some of the most important, such 

 as those produced by the tetanus and diphtheria bacteria, have 

 been shown to possess characters which separate them from 

 'Vaughan and Novy. Cellular toxins, Fourth edition, p. 32. 



