166 



THE VENOM OF HELODERMA. 



COMPARISON OF THE HEMOLYTIC INFLUENCE OF THE VENOM OF THE 

 HELODERMA SUSPECTUM AND HELODERMA HORRIDUM. 



All of the experiments which have been reported so far have been carried 

 out with venom of the Heloderma suspectum, but since we were able to obtain 

 venom from the Heloderma horridum it appeared advisable to compare the 

 activity of these two venoms. We tested the action of the two venoms com- 

 bined with lecithin or heated dog serum on guinea-pig, rabbit, and turtle cor- 

 puscles. When lecithin was added to the two venoms with all three kinds of 

 corpuscles, slightly more hemolysis was observed in the tubes containing the 

 venom of Heloderma horridum. An example of an experiment with turtle cor- 

 puscles will serve to show this difference. 



/ c.c. of a 5 per cent suspension of turtle corpuscles and lecithin, 0.05 mg. 



A similar difference was observed when heated dog serum was used as 

 activator; here again the Heloderma horridum venom tubes showed slightly 

 more hemolysis. 



We also tested the action of heated rabbit and guinea-pig sera as activa- 

 tors for the Heloderma horridum venom, with guinea-pig corpuscles. 



The Heloderma horridum venom was not activated by either of these sera ; 

 its behavior was therefore similar to that of the Heloderma suspectum venom. 



We may conclude that the venom of Heloderma horridum and Heloderma 

 suspectum are identical in their action. 



INFLUENCE OF HEATING ON THE HEMOLYTIC POWER OF 



HELODERMA VENOM. 



It has been shown that heating the venom of various snakes to high temper- 

 atures, 100 C, for 30 minutes, does not destroy their hemolytic activity. In 

 the case of the venom of the Heloderma, we have shown that boiling does not 

 destroy its toxic property, although it may occasionally lessen it to a very 

 slight extent. In experiments to determine the heat resistance of the hemo- 

 lytic substance of heloderma venom, fresh venom and drj', dissolved venom 

 were used, with lecithin as an activator. The effect of venom-lecithin mix- 

 tures was tested on guinea-pig, Heloderma, and turtle corpuscles, and in the 

 main the results were similar with all these corpuscles. The turtle and guinea- 

 pig corpuscles were hemolyzed to the same extent by the various specimens of 

 heated venom, while heloderma corpuscles were more resistant to the heated as 

 well as to the unheated venom. 



