80 



VENOMOUS SNAKES AND THE PHENOMENA OP THEER, VENOMS 



series they employed the venom of Crotalus adamanteus, Crotalus terrificus, 

 Ancistrodon piscivorus, and of Cobra, but the results recorded here speak only 

 for the globulins of Crotalus adamanteus. They laid special stress upon this, 

 as they did not find the globulins of all venoms to be identical, a fact which 

 agrees very well with the later investigations by certain authors on venoms 

 other than Crotalus adamanteus. 



(a) Water-venom globulin: When a sufficient amount of distilled water 

 is added to venom a whitish precipitate occurs which settles to the bottom 

 of the glass, leaving in the course of a few hours a perfectly clear supernatant 

 fluid. If sufficient water has been added at first, the addition of more water 

 to the clear liquid will not cause any further precipitate. The precipitate is 

 this fraction. 



(b) Copper-venom globulin: After separating water- venom globulin the 

 filtrate can be gradually precipitated by carefully adding a few drops of a 

 10 per cent solution of copper sulphate. An excess of this reagent causes a 

 complete or a partial re-solution of the precipitate. After standing 24 hours, 

 during which precipitation increases, the deposit is separated by filtration as 

 usual. The filtrate will produce no more precipitate by adding another few 

 drops of cupric sulphate and standing another 24 hours. This fraction did 

 not give any reaction for copper, as tested with ammonia, or ferrocyanide 

 and acetic acid, and was therefore considered not to be a salt of this metal. 



(c) Dialysis-venom globulin: The filtrate, after the separation of the two 

 globulins above mentioned, still contains some coagulable proteins (by boiling). 

 The filtrate yields also a considerable amount of precipitate when dialyzed 

 against running water for 24 hours. This is the last fraction of the coagula- 

 ble proteins of venom. The only proteins still left in the filtrate belong to 

 the non-coagulable proteins and were placed by them among the peptones. 



Table 3. 



Finally, the venom peptone was prepared by dialysis. Elimination of 

 the coagulable proteins by boiling was unsatisfactory, because it never gave 



