220 TOXINES AND ANTITOXINES. 



The differences observed in the action of different snake 

 toxines can for the most part be attributed to the variations 

 in the proportions of the separate components, sometimes the 

 neurotoxine and sometimes the hsemorrhagine predominating. 

 Occasionally, too, the hsemolytic principle doubtless has some 

 toxigenic effect. 



The venoms of the crotalus, trigonocephalus, and cerastes are 

 distinguished from cobra poison by their much greater activity, 

 especially as regards the local effects (oedema, necroses, &c.). 



Moreover, while, according to CALMETTE, cobra poison can be 

 entirely deprived of its local irritant action by heat, the toxicity 

 of crotalus venom is stated by M TAR LAND l to be almost com- 

 pletely destroyed by the same treatment. Owing to the terrible 

 injuries produced, M TAR LAND was absolutely unable to produce 

 immunity by means of subcutaneous injection, and only suc- 

 ceeded in his purpose by the use of intravenous injections. 



As was found by FLEXNER and NOGUCHI, the characteristic 

 poisonous constituent in the venom of crotalidce is exclusively the 

 hcemorrhagine, while the neurotoxic component, which predo- 

 minates in cobra venom, has here only a very slight share in 

 the effects. The venoms of the mocassin snake and copper-head 

 snake (Ancistrodon) contain both components. 



This explains why the venom of the crotalus and of other 

 allied species of snakes (Pseudechis, &c.) produce areas of haemor- 

 rhages that are not caused by cobra venom ; this characteristic 

 was closely studied by WEIR MITCHELL and REICHERT. The 

 poisonous constituent that produces the haemorrhage is destroyed 

 at 75 C., while the venom simultaneously loses part of its 

 toxicity, so that not less than ten to twenty times the original 

 lethal dose is required to cause death ; the symptoms resemble 

 those produced by cobra venom, and must therefore be attributed 

 to the neurotoxine. 



It would be conceivable that the general toxicity in this case 

 might be due to the hsemolysine. 



But the hsemolysine can be eliminated, as we shall presently 

 show, by making it combine with susceptible erythrocytes, 

 without destroying the general toxic power. 



Hence, it follows that the poison that causes the haemorrhage 

 is not identical with the true hsemolysine any more than it is 

 with the neurotoxine, but that a third individual poison is 

 present, to which FLEXNER and NOGUCHI have given the name 

 hcemorrhagine. 



1 M'Farland, " Immunisation of Animals to Rattlesnake Venom," abstr., 

 Centralbl.f. Eakt., xxix., 496, 1901. 



