HEMOLYTIC PROPERTIES OF HELODERMA VENOM. 159 



COMBINATION OF HEATED SERA AND HELODERMA VENOM. 



In testing the influence of heat on the activating properties of the various 

 sera, especially guinea-pig, rabbit, sheep, or heloderma serum, it was found 

 that 60 C. for 30 minutes did not transform them into activators. 



Dog serum, when heated to 56, 60, or 70 C. for 30 minutes, lost its 

 inherent hemolysins, but did not lose its activating property when combined 

 with venom. It then hemolyzed guinea-pig, horse, dog, and heloderma; the 

 last named corpuscles were, however, only slightly hemolyzed by this com- 

 bination. As in experiments with unheated dog serum the addition of heated 

 dog serum to venom did not hemolyze frog or turtle corpuscles. 



Horse serum, when heated to 60 C. retained its action as an activator, and 

 combined with venom caused hemolysis of horse, dog, rabbit, or guinea-pig 

 corpuscles. The heated horse serum alone did not cause hemolysis of any of 

 these corpuscles. 



Turtle serum, when heated, was able to activate venom for guinea-pig and 

 rabbit corpuscles, but not for turtle corpuscles. The quantities of these three 

 sera that had to be added to venom to cause hemolysis were approximately the 

 same before and after heating; the heating did not change the activating 

 properties of these three sera to any marked extent. 



Calmette has shown that in conjunction with cobra venom many sera 

 heated to 62 C. were better able to cause hemolysis of red cells than the un- 

 heated sera. He believed that the heating destroyed a natural antihemolysin 

 which was thermolabile, whereas the activating constituent was thermostable. 

 This activating constituent he considered a " substance sensibilatrice. " 



Kyes found that heating changed the properties of the activating sera. 

 Ox serum heated to 56 C. loses its activating power, but when heated to 65 C. 

 or higher it regains its hemolytic power and is then more powerful than with 

 the fresh serum. He also found that horse serum serves as an activator when 

 fresh as well as when heated to 56 or 100 C., and he believed the activating 

 substance of horse serum was lecithin. Our results make it certain that the 

 ordinary serum complement is not concerned in the venom hemolysis, but that 

 a certain thermostable substance already present in the fresh sera is responsible 

 for the activating action of the sera. 



INHIBITORY ACTION OF VARIOUS SERA ON HEMOLYSIS BY HELODERMA 

 VENOM AND DIFFERENT ACTIVATORS. 



We tested the inhibitory action of different sera (horse, guinea-pig, turtle, 

 heloderma, and rabbit serum), heated and unheated, upon the hemolysis of 

 erythrocytes of different species by the combination of venom and different 

 activating substances. 



We used horse, guinea-pig, turtle, heloderma, and rabbit serum and the 

 corpuscles of guinea-pig, horse, Heloderma, turtle, rabbit, and dog. In the 

 majority of experiments lecithin was the activator used. 



Guinea-pig serum has approximately the same action whether heated or 

 not heated. It inhibits hemolysis of guinea-pig, horse, heloderma, and turtle 



