570 BA CTERIOLOG Y. 



examination of an animal injected with the toxin, certain 

 characteristic lesions which have been brought about by 

 the action of the toxin. For instance, there is always 

 very marked hyperaemia and necrosis at the point of 

 injection. Certain internal organs also show almost 

 constantly marked hyperaemia, especially the adrenals 

 and the chain of hsemolymph glands lying in the retro- 

 peritoneal space. Histological studies of the different 

 tissues have revealed certain other lesions attributable 

 to the action of the toxin, especially areas of necrosis in 

 the liver and other organs. Our knowledge of the man- 

 ner in which sudden death is frequently brought about 

 during convalescence from diphtheria shows that the 

 fatal result in such conditions is, however, not due to 

 any of the alterations or reactions of the toxin that have 

 so far been considered. Death during the period of con- 

 valescence from diphtheria is due to degenerations occur- 

 ring in the nerve trunks of important nerves, especially 

 of the pneumogastric. With this fact in mind it seems 

 evident that we must regard this form of toxic action of 

 diphtheria toxin as of far greater moment. In poison- 

 ing with diphtheria toxin then we also see secondarily 

 at least, if not primarily, a direct affinity of the toxin 

 for nerve cells. 



With regard to the action of the endotoxins the facts 

 at hand are far less satisfactory. According to Ehrlich's 

 side-chain theory the amboceptors formed in the serum 

 as the result of recover)' from infection have been formed 

 as the result of the overproduction of certain cell recep- 

 tors, because of the action of the bacteria themselves or 

 their endotoxins upon certain tissue cells. When we 

 come to look for evidence as to the particular organs or 

 cells that are aifected in different infections we find very 



