Historical sketch on Immunity 525 



with overturning this hypothesis, these observers have sought to build 

 upon its ruins new theories capable of offering a better explanation of 

 the phenomena of immunity. I must here confess at the outset that 

 these attacks have been much more important than those coming 

 from the pathologists and pathological anatomists, and have led to 

 discoveries of the greatest value. 



One of Fodor's experiments 1 , one not altogether new, served as the 

 point of departure for much work and for a large series of objections 

 directed against the phagocytic theory. The Hungarian investigator 

 found that the defibrinated blood of the rabbit was capable of 

 destroying in vitro a great number of anthrax bacilli. From this 

 it was concluded that the fluids of the living body possessed a 

 bactericidal power sufficient to explain the immunity against infective 

 micro-organisms. The destruction of the anthrax bacillus by defibri- 

 nated blood was confirmed by a young American investigator of great 

 talent, Xuttall 2 , who carried out an important work on this subject 

 in the laboratory and under the direction of Fliigge at Breslau. He 

 was able to follow step by step, by the observation of anthrax bacilli 

 on the warm stage, their degeneration under the action of the 

 defibrinated blood. This destruction of the bacilli took place outside 

 the phagocytes. The same phenomenon could be shown by the 

 method of gelatine plate cultures. The bacilli, subjected to the 

 influence of the defibrinated blood of rabbits and other vertebrates, 

 usually died or were markedly injured. The blood when heated 

 to 55 C. completely lost its bactericidal power. 



These observations, perfectly exact in every detail, gave Fliigge 8 

 and his assistant Bitter 4 the opportunity to criticise vigorously the 

 theory of phagocytosis. The cells were said to be incapable of [549] 

 ingesting living micro-organisms ; these latter must be previously 

 destroyed by the bactericidal action of the body fluids, and it was only 

 their dead bodies which were devoured by the phagocytes. 



Fliigge based his criticism upon considerations of a general 

 character and upon observations made mainly by Nuttall. " There is 

 no necessary point of analogy," says the learned Breslau hygienist, 

 "between the ingestion of food and the struggle against infective 



1 Deutsche meet. Wchnschr., Leipzig, 1886, S. 61 7 j Arch. f. Hyg^ Munchen 

 u. Leipzig, 1886, Bd. iv, S. 129. 



2 Ztschr.f. Hyg., Leipzig, 1888, Bd. iv, S. 353. 



3 Ztschr.f. Ht/g., Leipzig, 1888, Bd. IT, S. 223. 

 * Ztschr.f. Hyg., Leipzig, 1888, Bd. iv, S. 318. 



