162 



THE VENOM OF HELODERMA. 



The influence of guinea-pig and heloderma serum are approximately the 

 same in experiments in which guinea-pig corpuscles were mixed with lecithin 

 and venom. 



When heated dog serum was utilized as activator in place of the lecithin, 

 the addition of heated heloderma serum in large quantities prevented hemolysis. 



Mixture of 0.1 mg. of venom and 0.1 c.c. of heated dog serum and guinea-pig corpuscles 

 (2 c.c. of a 5 per cent suspension). 



Here again the inhibitory action of heloderma serum is more marked than 

 that of guinea-pig serum, since 0.7 c.c. of the latter was not sufficient to com- 

 pletely prevent hemolysis, whereas 0.5 c.c. of the heloderma serum does prevent 

 hemolysis by venom and dog serum. 



From these experiments we may conclude that heloderma serum pos- 

 sesses a somewhat greater inhibitory power than guinea-pig serum and that it 

 protects its own corpuscles best of all. It also seems that guinea-pig corpus- 

 cles are more strongly protected than turtle corpuscles by heloderma as well 

 as by guinea-pig serum. 



Horse serum, when combined with venom and lecithin, does not prevent 

 hemolysis. The influence of these combinations was tested on horse, rabbit, 

 dog, and guinea-pig corpuscles and both heated and unheated horse serum was 

 used. The results were the same in all cases; no inhibition was evident, and 

 indeed in most experiments hemolysis appeared more rapidly in the tubes con- 

 taining serum, lecithin, and venom than in those containing only lecithin and 

 venom. It is evident that horse serum does not inhibit hemolysis by venom 

 and lecithin. 



Turtle serum appears to have a slight inhibitory action when venom and 

 lecithin act on turtle corpuscles. This holds good only in the case of the 

 unheated serum. 



Mixture of 0.1 mg. of venom and 0.1 mg. of lecithin. 



