110 THE LAND-MARKS OF 



affected, — when an overwhelming dose of poison 

 is injected into the areolar tissue or directly into 

 a vein. The heart then is said to stop in 

 systole. This is, however, very questionable. 

 veMm°OT°tho There is either a distinct difference in the 



'systemT action of the venom of the crotalus and that of the 

 cobra, or some error of observation, since the 

 observations of Mitchell and those of Brunton 

 and Fayrer exhibit a material discrepancy. 

 While Mitchell states that no increase of pressure 

 followed the introduction of venom into the 

 system, therefore it exerts no marked influence 

 in contracting the capillaries, an experiment 

 made by Fayrer and Brunton shews that the 

 pressure did rise considerably, on the injection 

 of the poison into a vein ; and they remark — " The 

 fact that the blood-pressure sank slowly and did 

 not fall below 30 even after the heart had almost 

 entirely ceased shows that the arterioles were much 

 contracted." In Mitchell's experiment the differ- 

 ence fell in three minutes from 16 mm. to 4 mm. 

 representing a diminution of 10 mm. five minutes 

 - after the infliction of the bite of the snake. 



Action of Weir Mitchell found that the motions of the 



venom upon 



movSm^nt intestinal canal were in no way affected. This 

 assertion applies equally in cases of cobra-bite. 



