156 THE VENOM OF HELODERMA. 



in most cases we tested the action of the combination of the various sera with 

 venom on the corpuscles of different animals. 



We have found that the serum of the guinea-pig, rabbit, sheep, ox, Hclo- 

 derma, or frog will not serve as activators for the heloderma venom. 



The guinea-pig serum has been tested with washed sheep, dog, rabbit, and 

 guinea-pig corpuscles, but failed to hemolyze any of these corpuscles with or 

 without venom. Guinea-pig serum if added to ox corpuscles, either with or 

 without venom, caused a minute trace of hemolysis in both series of tubes; no 

 distinct difference could be detected between the hemolysis in the tubes con- 

 taining serum alone and the combination of serum and venom; guinea-pig 

 serum did not therefore serve as an activator for the venom. 



Rabbit serum also was tested with rabbit, guinea-pig, ox, sheep, and dog 

 corpuscles. With rabbit and guinea-pig corpuscles, no, or only a trace of, 

 hemolysis was observed either with rabbit serum alone or with rabbit serum 

 and venom. With ox and sheep corpuscles the rabbit serum alone, as well as 

 the combination of serum and venom, produced slight hemolysis, which was, 

 however, as marked in the control tubes as in the venom-serum tubes. In one 

 case rabbit serum combined with the venom produced more hemolysis of dog 

 corpuscles than the same quantities of the serum alone. In other cases, how- 

 ever, the rabbit serum, when combined with venom, did not hemolyze the dog 

 corpuscles, so that in this isolated case, when rabbit serum seemed to serve as an 

 activator for the venom, some accidental circumstances must have been active. 



Sheep serum was tested with guinea-pig, rabbit, dog, sheep, and ox cor- 

 puscles. The ox corpuscles were slightly hemolyzed by sheep serum alone, as 

 well as in combination with venom, but no difference was found between the 

 degree of hemolysis in the two series of tubes. With the other corpuscles 

 neither the sheep serum alone nor the mixture of sheep serum and venom pro- 

 duced hemolysis. 



Ox serum was tested with the same corpuscles, namely, guinea-pig, rabbit, 

 dog, sheep, and ox; it showed more marked hemolytic power than other serums, 

 but did not activate the venom. 



Frog serum was tested only with frog corpuscles, but did not cause hemo- 

 lysis in combination with venom. 



Heloderma serum was also tried with guinea-pig or heloderma corpuscles, 

 and neither alone nor mixed with venom produced hemolysis. When helo- 

 derma serum was added to rabbit corpuscles, either alone or in combination 

 with venom, the same degree of hemolysis occurred in both sets of tubes. 



We may therefore conclude that the sera of guinea-pig, rabbit, ox, sheep, 

 frog, or heloderma do not serve as activators for the heloderma venom. Cal- 

 mette found in the case of cobra venom that unheated sera could not activate 

 venom, but when sera was heated to a temperature above 62 C. it would 

 activate venom. 



We therefore tested 0.1 and 0.2 c.c. guinea-pig and rabbit serum heated 

 to 63 C. for 30 minutes in combination with 0.1 and 0.2 mg. venom and 2 c.c. 

 of a 5 per cent suspension of rabbit and guinea-pig corpuscles. In no case did 



