XII. ON THE SENSITIZERS OF SERA ACTIVE AGAINST 

 ALBUMINOUS SUBSTANCES * 



BY DR. OCTAVE GENGOU. 



The experimental study of anticholera immunity in vivo led 

 Pfeifferf to discover the phenomenon that now bears his name, 

 which consists in an extracellular granular transformation of 

 Koch's vibrios in the peritoneal cavity of guinea-pigs vaccinated 

 against cholera. The same phenomenon also occurs in the 

 peritoneum of normal guinea-pigs, as Pfeiffer himself showed, on 

 injecting cholera vibrios mixed with serum from well-immunized 

 animals. 



This destructive transformation of vibrios indicates an energetic 

 bactericidal action. Pfeiffer attributed to the fixed endothelial 

 cells of the peritoneum the property of rapidly secreting substances 

 harmful to the vibrios whenever these organisms were injected into 

 the peritoneal cavity. Metchnikoff $ soon showed that this inter- 

 pretation is incorrect. He was able to produce the granular change 

 of vibrios in vitro by mixing them with preventive serum plus the 

 peritoneal exudate of a normal guinea-pig; this exudate contains 

 leucocytes, but no endothelial cells. 



Pfeiffer in his experiments failed to obtain a transformation on 

 mixing the vibrios in vitro with the serum of vaccinated animals. 

 From our present knowledge it is evident that the serum he 

 used must have been too old to have retained its bacteriolytic 

 properties. 



Bordet indeed produced Pfeiffer's phenomenon in vitro by 

 simply mixing the vibrios with fresh preventive serum. He further 



* Sur les sensibilisatrices des se"rum actifs centre les substances albuminoi'des. 

 Annales de 1'Institut Pasteur, XVI, 1902, 734. 

 t Pfeiffer, Zeit. fur Hyg. XVIII, 1894. 

 } Metchnikoff, Annales de PInstitut Pasteur, June, 1895. 

 Bordet, see p. 66. 



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