THE PJSYSIOtOGY OF POtSONtNG 1^7 



(0"1 milligramme for the guinea-pig) as when the injection is made 

 in the peritoneum or beneath the skin. 



With the venom of Crotalus heated for half an hour at 75° C, 

 which contains but very little neurotoxin and has lost all its 

 hsemorrhagic properties, 0'5 milligramme introduced directly into 

 the brain of the guinea-pig only produces transitory and non-lethal 

 effects ; while, if fresh venom be employed, 0'05 milligramme is 

 sufficient to cause death in three hours, with severe heemorrhagic 

 lesions. Now this dose is twenty times smaller than the minimal 

 lethal dose for a subcutaneous injection. 



It is evident that the harmful matter, in the particular case 

 of CrotoZws-venom, is not the neurotoxin, but an altogether different 

 substance, termed by Flexner and Noguchi hcemorrhagin, which 

 acts upon the elements of the blood and upon the endothelium 

 of the blood-vessels. 



We shall meet with this substance again in almost all Vipbeine 

 venoms, and shall study it further on. 



