MECHANISM OF THE ANAPHYLACTIC SHOCK 149 



symptoms of the anaphylactic shock in dogs to wliat we see in 

 "peptone" poisoning in the same animal. In both instances there 

 is a marked drop in blood pressure, incoagulability of the blood and 

 leukopenia, and in both cases it is possible to counteract the 

 poisonous effect by the administration of barium chloride. In other 

 animals, however, such as the guinea-pig, "peptone" apparently plays 

 little or no role; Witte peptone, indeed, is quite harmless for this 

 animal, which, after all, is the most sensitive to anaphylactic shock. 

 Barium chloride, moreover, does not prevent the latter, and a primary 

 drop in blood pressure, such as we see in dogs, does not occur. But 

 it is conceivable that while "peptone" does not play an important 

 role, if indeed any, that other poisonous substances may be formed 

 which may be quite harmless for the dog, but highly toxic for the 

 guinea-pig. 



Whether or not the anaphylactic poisons which are split off from 

 different antigens by the antiserum of a given animal or animal 

 species are identical is unknown, but does not seem unlikely in 

 view of the uniformity of the anaphylactic symptom complex. 



In speaking of the anaphylactic poison in the foregoing pages we 

 have repeatedly made use of the term anaphylatoxin which has 

 come into common use so extensively that it would indeed be diffi- 

 cult to replace it. This term, of course, suggests that the poison 

 actually belongs to the class of toxins which, as we have seen, are 

 characterized by the fact that on immunization they give rise to 

 a corresponding antitoxin. As yet there is no evidence, however, 

 to show that it is possible to immunize against this poison, and it 

 would accordingly be better not to use the term anaphylatoxin at 

 all, or if so, to bear in mind that by "toxin" in this case we merely 

 mean a poison in the more general sense of the word. 



Mechanism of the Anaphylactic Shock. If now we inquire into 

 the mechanism by which the anaphylactic shock is called forth, the 

 very suddeness of the onset and the lightning course of the reaction 

 suggest a cerebral origin of the symptoms in question. As a matter 

 of fact Besredka has shown that the shock, in guinea-pigs at least, 

 is particularly severe if the anaphylactic poison is injected intra- 

 cerebrally, and that it is then exceptional for an animal to escape 

 death, while with the usual intraperitoneal method nearly 75 per 

 cent, recover. Quite in accord with this view also is the observation 

 that it is possible either to suppress or to mitigate the severity of 



