SNAKE VENOM. 431 



Radium is said to destroy the toxicity of venom 

 (Physalix). 



The antivenin of Calmette is obtained by im- 

 munizing horses with a mixture of venoms (80 

 per cent, cobra, 20 per cent, viperine venom) which 

 are attenuated before injection. Six months are 

 required to produce a strong serum. The claim 

 of Calmette that his serum is effective against all 

 snake-venoms is erroneous. It neutralizes those 

 venoms the toxicity of which depends largely on 

 neurotoxins and hemolysins, but has little influ- 

 ence on rattlesnake poison, the essential toxin of 

 which is hemorrhagin. Antivenin for the rattle- 

 snake and water-moccasin may be prepared by im- 

 munization with the corresponding venoms which 

 have been attenuated by weak acids. Noguchi has 

 produced serum of such strength that it promises 

 to be of practical value in the treatment of rattle- 

 snake bites. 



As indicated previously, the action of venom is 

 preceded by no appreciable incubation period; 

 hence, an antitoxin to be effective must be admin- 

 istered not later than a few hours after the bite 

 has occurred. Noguchi found in relation to anti- 

 venin for the rattlesnake that the quantity of anti- 

 toxin necessary to save was quadrupled three hours 

 after intravenous injection of two fatal doses of 

 venom. Fortunately the venom is less toxic when 

 introduced subcutaneously. 



II. OTHER ZOOTOX1NS. 



Phrynolysin, which is present in the blood and 

 skin of certain toads, has been studied especially 

 by Proscher. It is a thermolabile, hemolytic toxin 



