EFFECTS OF SNAKE VENOM. 



5 



action of neurotoxin than to that of haemorrhagin.* Crotalus venom is effective 

 chiefly in those instances in which the local lesions are marked ; while in instances 

 in which it acts independently of the local lesions a far larger dose, in keeping with 

 its small proportional content of neurotoxin, is required to produce fatal results. 



Snakes and frogs succumb easily to cobra venom, but they are relatively insus- 

 ceptible to Crotalus and moccasin venoms. They would seem to be entirely resistant 

 to the action of haemorrhagin. Turtles are more susceptible to all venoms than the 

 foregoing animals, and fishes exceed turtles in this respect. The grasshopper suc- 

 cumbs only to large doses of venom. Among the crustaceans the horseshoe crab is 

 almost insusceptible, and other species of crabs are only moderately susceptible to 

 venom poisoning. The lobster is only moderately resistant. 



Excepting the earth-worm, all the worms with which I experimented showed a 

 low degree of susceptibility. While the first will die in toto if injected with venom, the 

 others show at times general effects, but they suffer only partial necrosis, from which 

 they finally recover. After separation of the dead parts the worms seem to have 

 been entirely restored. On the injection of Phascoloscoma with an enormous dose 

 of venom I have seen the muscular contractibility of the injected part disappear for 

 a period of a week or longer, but in the end it was recovered. If necrosis occurred 

 a slough was formed and was finally cast off. 



Upon the Echinodermata venoms produce little effect. The sea-urchin suc- 

 cumbed to all the venoms, while starfish and sea-cucumbers were not perceptibly 

 affected. 



The general toxicity of venoms upon the adult organism, as compared to their 

 special effects which are produced upon the embryological elementsf of the same 

 species, is found to be of considerable interest. The ova or spermatozoa of some 

 vermes and echinodermata are easily dissolved or fragmented by venoms, while the 

 adults of corresponding species are proved to be almost entirely insusceptible to 

 them . 



On the other hand, the reverse is possible. Thus, the eggs of the Fundulus — 

 a fish — are comparatively insusceptible to venoms, as they can be fertilized in the 

 sea water containing rather a large amount of venoms and development of the fertil- 

 ized ova progresses in the normal way, but the adults are found to be highly suscep- 

 tible to the same kind of venoms. 



A close examination as to the relation existing between the general toxicity and 

 the haematoxic powerj of venoms upon cold-blooded animals adds further interesting 

 as well as important facts to the understanding of the nature of the action of snake 

 venom in vivo. 



In the following tables the letter d indicates that death followed the experiment. 



* Flexner and Noguchi. The Constitution of Snake Venom and Snake Sera. Journal of 

 Pathology and Bacteriology, 1903, VIII, 396. 



t Flexner and Noguchi. On the Plurality of Cytolysms in Snake Venom. Univ. of Penna. 

 Medical Bulletin, 1903, July-August. 



\ Noguchi. The Effects of Venom upon the Blood of Cold-Blooded Animals. Univ. of 

 Penna. Medical Bulletin, 1903, July-August. 



