THEORIES OF IMMUNITY. 



powerful to explain the facts seen in the occur- 

 rence of immunity. Nuttall's work (Zeit. f. 

 Hyg., 1888, T. IV., p. 353, in which he refers to 

 Fodor's work as full of errors) was in the same 

 direction and of the first importance. It was 

 based upon observations on the warm stage with 

 the defibrinated blood of various animals, in 

 which it was shown that this same bactericidal 

 property was present — existing, of course, out- 

 side of the leucocytes, and that it could be de- 

 stroyed by subjecting it to fifty-five degrees 

 Centigrade. 



Such observations as these formed the first 

 foundation for the humoral theory of immunity, 

 and served as the starting point for innumerable 

 experiments, all of which were intended to show 

 that the theory of phagocytosis had absolutely 

 no foundation in fact. 



Behring was one of the first to take up the 

 bactericidal property of the blood as explaining 

 immunity. He (Cent. f. klin. Med,, 1888, No. 

 39) had discovered the remarkable power of the 

 blood of the white rat to destroy anthrax bacilli 



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