HEMOLYTIC PROPERTIES OF HELODERMA VENOM. 



163 



We can state that heated turtle serum does not inhibit hemolysis of turtle 

 or guinea-pig corpuscles by venom and lecithin ; indeed the addition of heated 

 turtle serum seems to increase the hemolysis. It does appear, however, that 

 unheated turtle serum inhibits, at least to some extent, the hemolysis of turtle 

 corpuscles by lecithin and venom. The most plausible explanation for the 

 action of turtle serum seems to be as follows : In turtle serum both an acti- 

 vating as well as an inhibiting substance exists. In heated turtle serum the 

 activating substance prevails to a greater extent than in the unheated serum. 

 If a combination of venom and lecithin is used the activating substance of 

 turtle serum can act only to a slight extent, but it is able to neutralize the 

 inhibiting substance. 



Rabbit serum acts in a somewhat irregular manner, its action varying with 

 different sera and different corpuscles. 



With rabbit corpuscles the rabbit serum prevented hemolysis in almost 

 every case ; with guinea-pig corpuscles the rabbit serum prevented hemolysis in 

 three out of five experiments; while with horse corpuscles hemolysis was pre- 

 vented in only two out of five experiments. 



Mixture of 0.05 mg. lecithin, 0.01 c.c. of venom, and 2 c.c. of suspension of corpuscles. 



The inhibitory action was quantitatively most marked when rabbit cor- 

 puscles were used, and least marked when horse corpuscles were used. As a 

 rule when a certain specimen of rabbit serum did not protect the horse corpus- 

 cles it likewise had no, or only a very slight, protective action with the guinea- 

 pig corpuscles. 



Heated and unheated rabbit serum acted in the same manner; a certain 

 serum which when heated inhibited the hemolysis of rabbit corpuscles by 

 venom and lecithin acted in the same manner when unheated; while another 

 serum, which did not protect horse corpuscles when heated, showed no protec- 

 tive power when it was added to the tubes containing horse corpuscles, lecithin, 

 and venom without having previously been heated. 



When heated dog serum was substituted for the lecithin in a mixture with 

 guinea-pig corpuscles, rabbit serum showed as much protective power as when 

 lecithin was used. 



Rabbit serum which inhibited hemolysis by venom and lecithin, inhibited 

 also the hemolysis by venom and heated horse serum in mixtures with horse, 

 rabbit, and guinea-pig corpuscles, and, as with lecithin, the inhibition was most 

 marked with rabbit corpuscles and least marked with horse corpuscles. 



