Anaphylactic and Immune Reactions. 175 



98 (1162) 



Analysis of the anaphylactic and immune reactions by means of 

 the isolated mammalian heart. 



By W. H. Manwaring, Arthur R. Meinhard and Helen 



L. Denhart. 



[From the Department of Bacteriology and Immunity, Leland Stan- 

 ford, Jr., University.} 



The heart of a rabbit sensitized to goat serum, tested in a 

 blood-free condition by perfusion with 7 per cent, to 10 per cent, 

 goat serum, is more resistant than a normal rabbit heart similarly 

 tested. The increased resistance is shown by the absence of the 

 initial tachycardia, the absence or delayed development of the 

 secondary tachycardia, and a prolongation of the life of the isolated 

 organ. 



Hearts of rabbits sensitized or immunized by repeated in- 

 jections with goat serum, are more resistant than those sensitized 

 with a single injection. 



Normal rabbit serum, corpuscles or defibrinated blood, added 

 to the perfusion fluid, decreases its toxicity. The antitoxic action 

 of defibrinated blood is apparently equal to the sum of the anti- 

 toxic actions of its serum and corpuscles. 



Anaphylactic rabbit serum similarly added usually markedly 

 increases the toxicity of the perfusion fluid. Such an anaphylactic 

 serum mixture may completely inactivate a normal heart within 

 from two to four minutes. Hearts of anaphylactic and immune 

 rabbits are more resistant than normal hearts to such mixtures. 



The active principle of the anaphylactic serum responsible for 

 this increased toxicity is thermo-labile, the toxin-increasing or 

 toxin-producing power being completely lost, if the serum is 

 heated to 6o° C. for 30 minutes. 



The active principle is not complement, since such inactivated 

 anaphylactic sera cannot be reactivated by the addition of un- 

 heated normal serum. 



The active principle is presumably not precipitin, since the 

 specific precipitins of rabbit serum are not destroyed, or at least 

 not completely destroyed, by heating the serum to 6o° C. for 30 

 minutes. 



