INFECTION 257 



cell and becomes active, presumably, only when the cells 

 are disintegrated, Such disintegration may occur as a 

 result of autolysis or self-digestion of the bacteria under 

 special conditions of artificial cultivation, or it may be seen 

 as the outcome of the lytic or solvent action of the resisting 

 body cells or fluids, either those of the infected animal or, 

 as in the case of the toxins and antitoxins, those of the 

 animal that has become tolerant in one way or another to 

 the activities of the bacteria in question. Endotoxins are 

 not liberated from the bacterial cells as a secretion or excre- 

 tion or manufactured as an extracellular by-product, as is 

 the case of the toxins, but are peculiarities of the protoplasm 

 of which the bacteria are composed. 



The escape of endotoxin from bacterial cells as a result 

 of autolysis is seen occasionally in old cultures that have been 

 kept for a time under more or less constant conditions. 

 It is probable that it occurs to a limited degree in all cul- 

 tures of endotoxic bacteria as a result of the death and final 

 dissolution of a smaller or larger number of individual 

 bacteria in such cultures. For want of a better interpre- 

 tation this liberation is supposed to be the result of a sort 

 of self-digestion by enzymes that are within the bacteria 

 as normal components. It is most conspicuously to be seen 

 in cultures of those endotoxic species that most readily under- 

 go those morphological changes commonly denominated as 

 involution or degeneration; the spirillum of Asiatic cholera 

 and the meningococcus may be cited as conspicuous illus- 

 trations. The fundamental mechanisms of this phenomenon 

 cannot be discussed with profit as little or nothing is known 

 of it. 



As in the case of toxins, the definite chemical nature of 

 endotoxins cannot be stated. Nevertheless Buchner isolated 

 17 



