SNAKE TOXINES. 221 



This poison is also present in cobra venom though its amount 

 is ten times less than in the venom of the mocassin snake and 

 one hundred times less than in that of the rattlesnake. 



Owing to the great variation in the proportions of the three 

 components, neurotoxine, hsemolysine, and hsemorrhagine, the 

 ratio between the lethal dose and the dose of hsemorrhagine, just 

 capable of detection, is also very variable. Thus, in the case 

 of cobra venom the lethal dose (O'l mgrm.) corresponds to one 

 hsemorrhagic dose, that of the venom of the mocassin snake 

 (0'2 mgrm.) to 20, that of copper-head venom to 60, and that 

 of rattlesnake venom (1*0 mgrm.) to 1,000 doses. 



The histological changes produced by hsemorrhagine in the 

 blood-vessels have been more closely studied by FLEXNER and 

 NOGUCHI. The effect is not one of diapedesis but of rents in the 

 walls of the blood-vessels, in which perforations are then formed. 

 Stases occur in the vessels and also giant cells which block the 

 small vessels. The red and white blood -corpuscles equally 

 escape. 



They attribute this perforation of the walls of the vessels to 

 a cytolysine having a specific action upon the endothelium of 

 the walls. 



On the other hand, WALL (loc. cit.) observed very marked 

 differences between the venoms of the colubrine cobra and the 

 viperine Daboia Ensseli, which cannot be accounted for solely by 

 the difference in the proportions of the separate components. 



Daboia venom very rapidly produces violent convulsions, in the course 

 of which death frequently ensues, and these are followed by paralysis 

 which does not, however, as in the case of cobra venom, specially affect 

 the breathing apparatus. Nor is the respiration in general acted upon so 

 rapidly by daboia venom. It invariably produces mydriasis, but there is 

 none of the salivation that is characteristic of cobra venom. Albuminuria 

 is invariably produced by daboia venom, but never by cobra venom. The 

 former is a very powerful blood poison. Hence, those infected with the 

 venom are still in great danger even after surviving the first stage of 

 convulsions and paralysis. Whereas in the case of cobra poisoning the 

 question of life or death is decided within a few hours, those bitten by 

 the daboia may die as late as the end of the second week. 



In fact, LAMB l was able to show that the haemolysine of the 

 daboia possesses an absolutely different amboceptor from that of 

 cobra venom (vide infra). 



Toxoids of Snake Toxine. The existence in snake toxine of 

 non-poisonous or only slightly poisonous toxoids with an im- 

 munising power has not been definitely determined, but is 

 probable. 



1 Quoted by Kyes, Berl. klin. Woch., 1903, No. 43. 



