ANAPHYLAXIS 359 



knowledge of anaphylaxis merely as it concerns the hypersuscepti- 

 bility incited in animals and man by treatment with various antigens, 

 such as animal sera and other proteins, which possess but slight 

 native toxicity or no toxicity whatever in themselves. 



The special problem of toxin hypersusceptibility ("Giftiiberemp- 

 findlichkeit" of von Behring) we will deal with later in a separate 

 section, since it is as yet very doubtful whether these phenomena 

 may justly be incorporated with true anaphylaxis as we now define 

 it, despite the admitted fact that attention was called to the prob- 

 lems of acquired susceptibility largely because of these toxin in- 

 vestigations. 



The earliest observation having direct bearing upon protein 

 anaphylaxis is one which Morgenroth discovered in the writings of 

 Magendie. Morgenroth 1 mentions that, in his "Vorlesungen liber 

 das Blut," published in 1839, Magendie describes the sudden death 

 of dogs which had been repeatedly injected with egg albumen. Al- 

 though Morgenroth, whose paper was written before the present 

 facts regarding hypersusceptibility were fully developed, attributes 

 these results to the action of precipitins, there can be little doubt as 

 to the anaphylactic nature of Magendie's results. 



A clear statement of the fundamental phenomena was given, also, 

 by Flexner, 2 in 1894. In describing certain experiments he says: 

 " Animals that had withstood one dose of dog serum would succumb 

 to a second dose given after the lapse of some days or weeks, even 

 when this dose was sublethal for a control animal." 



One of the experiments cited to justify this statement is as 

 follows : 



"Two rabbits received % of 1 per cent, and 1 per cent, of their 

 body weight respectively of dog's serum, twenty-four hours old, on 

 January 19, 1894. With the exception of hemoglobinuria, indisposi- 

 tion to move, and increased respiration, no ill effects were noted. 

 The animals still showed hemoglobinuria on the following day. 

 These symptoms disappeared and apparently the rabbits entirely 

 recovered. On February 12, 1894, each received 1 per cent, of their 

 body weight of dog's serum intravenously. A control animal also 

 received 1 per cent, of its body weight of the same serum. The two 

 animals that had been previously inoculated died in two and twelve 

 hours respectively; the control animal showed only hemoglobinuria 

 which disappeared after a day or two." 



The experiment here quoted is, as a matter of fact, a perfect ex- 

 ample of what we now know as "active sensitization." 



However, the isolated observations recorded above were neither 

 correlated nor followed out to their logical developments, and a 



1 Morgenroth. "Ehrlich Gesammelte Arbeiten," Transl., Wiley & Son, 

 N. Y., 1906; p. 332 footnote. 



2 Flexner. Medical News, Vol. 65, p. 116, 1894. 



