36 THE VENOMS OF CERTAIN THANATOPHIDEi!. 



This last experiment was repeated with the modification of leaving the acid in 

 contact with the venom for one-half hour before the addition of the water. It was 

 then injected as above without any obvious effects following. 



The destructive action of the acid on the venom of the Crotalus Jiorridus seems 

 to be the same if we can judge from the single experiment which follows. 



Experiment. — Powdered 0.015 gram dried venom and added 10 gtt. hydro- 

 bromic acid, which formed a muddy solution with a reddish color. 



5:18. Injected into the breast of a pigeon without any obvious effects within twenty-four 

 hours. 



The effect on the activity of Cobra venom, using similar quantities of venom and 

 acid is very different. 



Experiment. — Repeated the above, only substituting Cobra venom. 



4:48. Injected into the breast muscles of a pigeon. 



5:18. Sick; breathing difficult. 



5:30. Breathing more difficult; convulsive movements; inco5rdination. 



5:35. Dead. 



Tannic Acid. — The action of tannic acid upon albuminoids is so decided that we 

 might confidently expect, since we find the poisonous elements in venoms to be 

 proteids, that the activity of venom would be greatly diminished or entirely 

 destroyed by it. In one experiment made with the venom of the Crotalus ada- 

 manteus we found comparatively little effect. 



Experiment. — Dissolved 0.03 gram dried venom in a little distilled water and 

 added 1.5 c. c. saturated solution of tannic acid. 



3:35. Injected into the breast muscles of a pigeon. 



4:00. Droopy. 



4:45. The same. Following morning dead. 



It will be observed that there is a great delay in the action of the venom, possi- 

 bly due to the powerful local constrictive action of the tannic acid on the tissues, 

 and possibly, also, to a direct action of the acid on the venom itself. As death 

 may have resulted from the tannic acid we made a control experiment in which 

 1.5 c. c. saturated solution was injected into the breast of a pigeon. The animal 

 did not exhibit any signs of active poisoning, but it died at the end of the fourth 

 day. 



Alum. — We made but two experiments with alum, one with the venom of the 

 Crotalus Jiorridus and one with Cobra. 



Experiment. — Dissolved 0.015 gram dried venom in 0.5 c. c. distilled water and 

 added 3 gtt. saturated solution of alum (18° C), but no precipitate occurred; we 

 then gradually added powdered alum nearly to saturation, which caused precipita- 

 tion. The precipitate was filtered off, and the clear filtrate tested by the further 

 addition of alum to see if any more precipitation would occur, with a negative 

 result. The precipitate and filtrate were now mixed together and injected into the 

 breast of a pigeon without any poisonous result occurring within forty-eight hours. 



In another experiment in which 0.06 gram of dried Crotalus venom was used, 

 the animal died in forty-five minutes. 



