398 INFECTION AND RESISTANCE 



us is the following ingenious experiment of Pearce and Eisenbrey. 42 

 We cite their own description : 



"Our procedure has been to exsanguinate under ether anesthesia 

 a small, normal dog (A), and to transfuse this animal by Crile's 

 method with the blood of a larger sensitized dog (B) until the blood 

 pressure reached approximately its original level. After sufficient 

 blood had been obtained from B to raise the pressure of A the sensi- 

 tized dog was then bled to exsanguination and transfused from a 

 third normal dog (C) until its pressure reached its previous normal 

 level. At the proper moment the normal dog containing the blood of 

 the sensitized dog, and the latter containing the blood of the normal 

 dog, each received intravenously the toxic dose of horse serum. In 

 the former a fall in pressure does not occur, and in the latter it does, 

 thus proving that the phenomenon of anaphylaxis is due to a reaction 

 in the fixed cells, and not either primarily or secondarily in the 

 blood." 



Experiments similar in significance to those of Schultz have been 

 carried out by Dale, 43 who used as his indicator of cellular suscepti- 

 bility the uterine muscle of virgin guinea pigs. These experiments 

 have been confirmed by Weil. 44 Coca, 45 too, has added to the evidence 

 in favor of the cellular localization by experiments in which he prac- 

 tically repeated in guinea pigs the observations made by Pearce and 

 Eisenbrey upon dogs, adding a number of further important points 

 concerning the participation of the complement in anaphylaxis, 

 which we will take up directly. 



In regard to this problem of the localization of the anaphylactic 

 mechanism, then, we are confronted with two predominant lines of 

 evidence, each of which has seemed so well supported by experiment 

 that it has tempted investigators into the expression of positive opin- 

 ions and the formulation of theories. 



On the one hand, it is unquestionable that poisons can be pro- 

 duced by the action of complement upon antibody-antigen complexes 

 and that these poisons, injected into guinea pigs, produce symptoms 

 indistinguishable from anaphylactic shock. Here there seems to be 

 proof that anaphylaxis can be induced by agencies all of which are 

 available in the blood stream under the conditions under which the 

 phenomenon is observed. 



On the other hand, the experiments just cited permit of no doubt 



42 Pearce and Eisenbrey. Transac. of Congr. of Am. Ph. and Sur., Vol. 

 8, 1910. 



43 Dale. Journ. of Pharm. and Exp. Therap., Vol. 4, 1913. 



44 Weil. Journ. of Med. Ees., 27, 1913; 30, 1914. 



45 Coca. Zeitschr. f. Imm., Vol. 20, 1914. 



