34 IMMUNOLOGY 



Gaseous Gangrene. — Gaseous gangrene is not an infrequent 

 complication of severely lacerated Avounds. It is caused by CI. 

 welchii and a few other anaerobes and is characterized by necrosis 

 (death) of the tissues infected and the liberation of gas within 

 them. It has been quite definitely established that hemolytic 

 streptococci, growing in gas-bacillus infected wounds, exalt the 

 virulence of the anaerobes. In this wc have another type of 

 bacterial association. 



Diphtheria. — In diphtheria the organisms do produce a slight 

 infection of the mucous membrane and grow luxuriantly in the 

 inflammatory exudate. The disease is caused by the specific toxin 

 secreted by the bacteria and absorbed into the general circulation. 

 The disturbed physiological state is called diphtheria. Diphtheria 

 toxin causes degenerative changes in the motor nerves, heart 

 muscle, and vascular system. 



Endotoxins. — By means of extraction methods weakly anti- 

 genic endotoxins from members of the Salmonella, Proteus, and 

 Colon groups have been obtained by Raistrick and Topley (193-4), 

 Boivin and Mesrobenu (1937) and others. These endotoxins seem 

 to be carbohydrate-lipid complexes although a second but weaker 

 endotoxin, apparently a polypeptid. has been described. It has 

 been known that Shiga dysentery bacilli produce a specific exo- 

 toxin. Boivin and Mesrobenu (1937) made a chemical investiga- 

 tion of the toxins of Shiga dysentery bacilli. They report that 

 the exotoxin, which is produced by both R. and S cultures, is a 

 protein and acts on the central nervous system but not on the 

 gastrointestinal tract. They were able to isolate endotoxins of a 

 carbohydrate-lipid nature from both Shiga and Flexner dysentery 

 organisms. These endotoxins produced symptoms of acute gastro- 

 enteritis in animals. 



Phytotoxins and Zootoxins. — The mycologist and the para- 

 sitologist have been more interested in morphological studies, life 

 histories, and host-parasite reactions and relationships, than in 

 chemical and physiological studies of parasites. A great many 

 important physiological observations, however, have been recorded. 

 Soule (1925) and Salle (1931) are pioneers in the study of the 

 metabolism of protozoa. It is known also that the poisonous 

 mushroom Amanita pludloides produces a soluble toxin whose 

 properties have been studied by Ford (1910-11). Soluble toxins 



