NATURE OF THE ACTIVE PRINCIPLES 319 



properties but differ in antigenicity depending on the protein to 

 which they are attached. It is possible that there may also exist 

 toxic principles devoid of antigenicity if under some conditions 

 they are not linked to any protein at all. It seems, then, reasonable 

 to conclude that the active principles of the phenomenon ^vith 

 u'hich one is predominantly dealing in the ^vork described and 

 under conditions of their preparation presently employed are 

 highly antigenic and soluble factors. Findings of "variants" devi- 

 ating in their properties from the alcove active principles may be 

 expected and by no means invalidates the conception of their 

 nature offered in this monograph. 



As already said, studies comparing the properties of the active 

 principles Avith the true toxins are mainly made for the sake of 

 their definition. It is felt, ho^vever, that the importance of the 

 contribution is not as much in the identification of the nature 

 of the active principles as in the demonstration of a new mech- 

 anism of elicitation of injury in living tissues; in the demonstra- 

 tion of existence of a large group of toxin-like sid^stances requir- 

 ing this mechanism for their attack upon the animal tissues, 

 thereby introducing ne^v notions for our understanding of patho- 

 genesis of certain himran and animal spontaneous diseases, as will 

 be discussed in more detail in a subsequent chapter. 



RELATION OF THE ACTIVE PRINCIPLES OF THE 

 PHENOMENON TO ANAPHYLATOXINS 



In attempts to produce an anaphylactic poison in vitro, Ulrich 

 Friedemann (1909) allo^ved complement to act upon sensitized 

 beef red blood cells, interrupted the action by cooling at a 

 time just preceding the occurrence of hemolysis, and injected the 

 supernatant fluid of such mixtures into normal rabbits. The ani- 

 mals developed symptoms resembling anaphylaxis. 

 Friedberger (1910) did the following experiment: 

 One c.c. of a rabbit serum which precipitated sheep serum in a 

 dilution of 1: 10,000 was mixed with 30 c.c. of sheep serum diluted 

 1:50. The mixture was incubated at 37.5° c. for one hour and 

 incubated in the ice-box overnight. The hea\7 precipitate formed 

 Avas Avashed to remove all traces of serum and to it ^vere added 

 2 c.c. of fresh guinea pig complement. The mixture ^vas again 

 allowed to stand for twelve hours and the supernatant fluid was 

 injected into guinea pigs intravenously. In most cases the guinea 

 pigs sho^ved marked symptoms soon after the injection and died 



