SNAKE VENOMS, THEIR PHYSIOLOGICAL ACTION. 223 



Effect of heating Snake Poison. 



When a solution of snake venorn is heated the poison is affected 

 in two ways : — 



(1). Some of the proteids present become coagulated, in the same 

 way as the albumen of egg is coaojulated for breakfast. 



(2). The toxic power of the proteids which are not coagulated is 

 impaired, while their solubilities are not altered. 



Whether the toxic power is completely destroyed by heating or 

 not depends on the degree of heat used, the duration of time for 

 which it is applied, and the strength of the solution which is heated. 

 Different poisons are affected in diff'erent ways. Thus, while a 0*1 

 per cent, solution of Cobra venom can bo heated for half an hour at 

 73° C, with the result of only slightly diminishing its original toxicity, 

 heating a O'l per cent, solution of Daboia venom at the same temper- 

 ature for the same length of time completely destroys its toxic power, 

 so that large quantities can now be introduced into the blood stream 

 of an animal without causing any symptoms. 



You will appreciate from this, then, that we have arrived at the 

 stage when* we can say that the poison secreted by a Cobra is, in all 

 probability, of quite a different nature from the venom manufactured 

 by a Daboia. In this connection I may sa}--, without entering into 

 tedious details and long explanations, that I feel to-day in a position 

 to state, without fear of contradiction, that Cobra venom contains no 

 poisonous element which is contained in Daboia venom, and vice versa 

 that Daboia venom is necessarily quite free from any of the toxic 

 constituents of Cobra poison. 1 know that this opinion is in contra- 

 diction to the working hypothesis put forward by Martin of Mel- 

 bourne some years ago — an hypothesis which, however, was only 

 provisional and titted to the facts then available. 



Physiological Action of Venoms. 



We have, therefore, now to pass on to a brief consideration of the 

 manner in which each of these venoms brings about its fatal result 

 when injected into an animal. 



Let us begin with Cobra venom, the poison which has received 

 more attention from investigators than any other. If one injects 

 a solution of Cobra venom into a hot-blooded animal, no matter what 

 the species of the animal may be, one observes a train of symptoms 

 which there is no doubt points to the poison having acted directly 



