84 



THE VENOM OF HELODERMA. 



merits were made with the blood of the same animal, in which 2 c.c. of blood 

 were added to 3 c.c. of sodium-chloride solution and one in which 5 c.c. of undi- 

 luted blood were collected. The coagulation times of the various mixtures are 

 given below: 



Influence of venom on the coagulation of the rabbit's blood. 



From these experiments it is again evident that venom neither delays nor 

 accelerates noticeably the coagulation of the blood. 



Inasmuch as in the preceding experiment the individual variations were 

 marked and the quantities of venom used were large, another similar experi- 

 ment was performed. Into a series of test-tubes each containing 2 c.c. of 

 venom dissolved in 0.85 per cent NaCl solution 2 c.c. of rabbits' blood was 

 allowed to flow from a canula inserted into the carotid artery. 



The individual variations in this experiment, due to imperfections of tech- 

 nique, are relatively slight. There is little doubt that the admixture of venom 

 caused an insignificant acceleration of the coagulation that is not specific. Ad- 

 dition of a chemically inert foreign body in fine suspension would have had at 

 least an equally strong accelerating effect. 



We also used a third method, which had been employed by Noc in his 

 studies of the influence of snake venoms on the coagulation of the blood. For 

 this we obtained 100 c.c. of rabbit plasma kept liquid through the addition of 1 

 gram of sodium citrate. This citrate plasma coagulates readily after addition 

 of CaCl 2 . 



So much 0.85 per cent NaCl solution was added that the total volume in 

 each tube was 2 c.c. It was found that 0.4 to 0.6 c.c. of 5 per cent CaCl 2 

 caused a coagulation of this plasma in approximately 14 to 15 minutes. After 



