534 Chapter XVI 



destruction of the vibrios takes place without any co-operation on 

 the part of the phagocytes and exclusively by means of the body 

 fluids. The vibrios, before their complete destruction and solution 

 in the fluids of the body, are transformed into granules, presenting 

 the transfoimation to which we have given the name of Pfeiffer'sj 

 phenomenon. 



Several of Pfeifffer's pupils have confirmed his view in connection' 

 with the cholera vibrio, and have extended it to several other micro- 

 organisms such as the typhoid coccobacillus. The destruction of the 

 micro-organisms in these cases is brought about, according to Pfeiffer 

 and his collaborators, not by the alexins of Buchner, but by a separate 

 substance. The protective anti-infective serum contains it in an 

 inactive state only; but immediately this serum is introduced into 

 the body of a normal animal, the bactericidal substance is acted upon 

 by the endothelial cells and becomes " active," capable of destroying 

 a large number of vibrios. Pfeiffer has developed this theory more 

 especially in an article published in 1896, entitled "Ein neues 

 Grundgesetz der Immunit'atV Pfeiffer 's observation and his theory 

 built upon it gave a new lease of life to the humoral theory and for 

 some time many observers believed that the theory of phagocytosis 

 [558] was now finally overturned. FrankeP announced, in a public address, 

 that science in its progressive march has "discovered the methods 

 of defence employed by the animal organism against its most dreaded 

 enemies, methods which have nothing in common with phagocytosis, 

 which act quite independently of the phagocytes and manifest an 

 action so energetic that we may calmly eliminate all other factors." 

 This view is based on the discovery of antitoxins and the bactericidal 

 substance studied by Pfeifibr. 



It will be readily understood that as soon as I learnt of the 

 existence of a real extracellular destruction of micro-organisms I at 

 once began to study it in order to find out its real importance amongst 

 the phenomena of immunity. First of all, I examined Pfeifler's 

 phenomenon in connection with the cholera vibrio^, and I was able 

 to show that it was produced only under special conditions. The 

 pre-existent phagocytes must be greatly injured before the cholera 

 vibrios can be transformed into granules. Phagolysis (so I termed 

 this transitory damage to the phagocytes) is indispensable for the 



1 Deutsche med. Wchnschr., Berlin, 1896, SS. 97, 119. 



2 " Schutzimpfung und Impfschutz," Marburg, 1895. 

 2 Ann. de VInst. Pasteur^ Paris, 1895, t. ix, p. 433. 



