THE PARATYPHOID GROUP 34? 



(c) Toxins. Soluble toxins have not been demonstrated in cul- 

 tures of paratyphoid bacilli. Cathcart 1 and Franchetti 2 have shown 

 that minute amounts of autolysates of the organisms are rapidly fatal 

 to rabbits and other small laboratory animals. According to Cath- 

 cart, 3 the poisonous substance (endotoxin) liberated from the organ- 

 isms during autolysis is relatively thermostabile ; a brief exposure of 

 it to 100 C. does not completely destroy its potency. 



Classification and Identification of the Paratyphoid Group. It is pos- 

 sible to divide the Paratyphoid Group into two distinct types by their 

 reaction in milk: the alpha type, of which several strains have been 

 described, differing somewhat in their serological reactions; and the 

 beta type. The former appears to be limited to man, but the latter 

 comprises organisms which are rather widely distributed not only 

 in man but in the lower animals as well. The better known strains 

 of the beta type comprise not only B. paratyphosus beta, B. enteritidis 

 and the hog cholera bacillus (B. cholerae suis, B. suipestifer) mentioned 

 above, but B. psittacosis, obtained from infectious enteritis of parrots, 

 which produces a pneumonic infection in man. 4 B. icteroides, San- 

 arelli, originally supposed to cause yellow fever, but now known to 

 be indistinguishable from the hog cholera bacillus, the Danysz bacillus 

 of rat plague, and B. typhi murium, Loffler, obtained from epizootics 

 of rodents, B. sertrycke, de Nobele, and B. moorseele, van Ermengem, 

 from epidemics of meat poisoning, and B. morbificans bovis, Basenau, 

 isolated from a diseased cow, all belong to the same group. They 

 possess in common cultural characteristics which differ somewhat 

 quantitatively, but not qualitatively. Bainbridge and O'Brien 5 have 

 attempted to classify the organisms by agglutination and absorption 

 tests; they recognize four groups as follows: (1) B. paratyphosus 

 alpha; (2) B. paratyphosus beta; (3) B. suipestifer (hog cholera bacil- 

 lus), including B. psittacosis, B. sertrycke and some strains of B. 

 typhi murium; (4) B. enteritidis, including the Danysz bacillus, B. 

 morbificans bovis, and some strains of B. typhi murium. This clas- 

 sification, if substantiated, possesses the advantage of separating 

 those organisms which cause paratyphoid fever, the alpha and beta 

 types, from the bacilli more commonly associated with the lower 



1 Jour. Hyg., 1906, vi, 112. 

 2 Ztschr. f.-Hyg., 1908, Ix, 127. 



3 Loc. cit. 



4 Nocard, Conseil d'hygiene pub. et Salubrite du Dept. du Seine, Seance, March 24, 

 1893. 



5 Jour. Hyg., 1911, xi, 68. 



