THE ACTION OF VENOMS UPON ARTERIAL PRESSURE. 



85 



CHAPTER VIII. 



THE ACTION OF VENOMS AND THEIR ISOLATED GLOBULINS AND 

 PEPTONES UPON THE ARTERIAL PRESSURE. 



Section I. — Pure Venom. 



The experiments made on the blood pressure with venoms and their isolated 

 poisons were all made on rabbits. The manometer tube was connected with one 

 of the carotid arteries, and the injections were always made into the external 

 jugular vein unless otherwise noted. 



Eighteen experiments were performed with the venoms of different species of 

 serpents, and in all of them there was a distinct lowering of the blood-pressure. 

 It fell immediately after the injection, and indeed sometimes before injection was 

 complete, and the fall was generally so marked as to indicate a most profound action 

 of the poison upon some part or parts of the circulatory apparatus. If the dose be 

 not immediately fatal the pressure gradually rises, but finally undergoes a more or 

 less steady decline to death. At other times the pressure sinks without subsequent 

 rise until death ensues. 



The tendency in Cobra poisoning is to a decided rise of pressure following the 

 primary fall. In five out of six experiments with this venom the primary fall was 

 followed by a rise which went above the normal. 



Of the eighteen experiments, five were made with the venom of Crotalus ada- 

 manteus, in two of which the poison was given hypodermatically ; two with that of 

 the Crotalus horridus ; two with the venom of Ancistrodon piscivorus ; one each with 

 the poisons Ancistrodon contortrix, Crotalophorus miliarius, and Daboia Russellii ; 

 and six with the venom of the Cobra. In all cases ether was given freely to the 

 animal poisoned. 



Action of the Pure Venoms upon the Arterial Pressure in Normal Animals. 



Experiment No. 1. 



Normal 



Time: 



Pressure 



min. sec. 



m. m. 





126 



20 



126 



40 



126 



1 00 



124 



1 20 



122 



1 40 



120 



2 00 



IIS 



5 00 



114 



Injected into the thigh of a large rabbit 1 drop of fresh venom 

 from the Crotalus adamanteus. 



Clot formed in canula. 



