45 8 Spirillum Cholerse Asiaticse 



For a long time this bacterial destruction, known as 

 "Pfeiffer's phenomenon," could not be explained. If the 

 spirilla were placed in the immune serum, they were not 

 destroyed; that the serum of the infected animal did not 

 destroy them was evident enough from the existing choleraic 

 peritonitis which would progress to a fatal termination if not 

 checked by the serum, yet the combination of the serum of 

 the infected animal and the immune serum sufficed to bring 

 about bacteriolysis. At present the matter is fairly 

 clear. We now know that the failure of the animal's own 

 serum to destroy the bacteria probably depends upon 

 insufficient immune body. The immune body contained in 

 the immune serum could not produce any effect unless in 

 the presence of an additional amount of complementary 

 substance. 



When the inflammatory exudate of the infected guinea- 

 pig and the immune serum were combined, however, the 

 one furnished the necessary immune body, the other the 

 necessary complementary body, and the alexins were per- 

 mitted to act upon the bacteria which were immediately 

 destroyed and dissolved. 



Pf eiff er and Vogedes * have applied this ' ' immunity 

 reaction" to the differentiation of cholera spirilla in cultures. . 

 A hanging drop of a i : 50 mixture of a powerful anticholera 

 serum and a particle of cholera culture is made and ex- 

 amined under the microscope. The cholera spirilla at once 

 become inactive, and are in a short time converted into 

 little rolled-up masses. If the culture added be a spirillum 

 other than the true cholera spirillum, instead of being 

 destroyed the micro-organisms multiply and thrive in the 

 mixture of serum and bouillon. 



Sobernheim f found the Pfeiffer reaction specific against 

 cholera alone, and thought the protection not due to the 

 strongly bactericidal property of the serum, but to its 

 stimulating effect upon the body-cells; for if the serum be 

 heated to 6o-7o C., and its bactericidal power thus de- 

 stroyed, it is still capable of producing immunity. This, 

 of course, is in keeping with our present knowledge of the 

 immune body, which is not destroyed by such temperatures. 



The immunity produced by the injection of the spirilla 



*"Centralbl. f. Bakt. u. Parasitenk.," March 21, 1896, Bd. xix, 

 No. 11. 



\ "Zeitschrift fur Hygiene," xx, p. 438. 



