160 VENOMOUS SNAKES AND THE PHENOMENA OP THEIR VENOMS 



required respectively, o.oooi gin. of cobra, equaling i minimal haemorrhagic 

 dose; 0.2 mg. water-moccasin, equaling 20 minimal haemorrhagic doses; 

 0.6 mg. copperhead, equaling 60 minimal haemorrhagic doses; and 1 mg. 

 rattlesnake venom, equaling 1,000 minimal haemorrhagic doses. 



The above estimate would amply justify the view of Flexner and Noguchi 

 that the chief toxic constituent of crotalus venom resides in the haemorrhagin. 



Morgenroth has also shown that the haemorrhagin of crotalus venom is 

 extremely sensitive to the influence of acids. This investigator found that 

 the inactivation of haemorrhagin can be brought about by a very weak dilu- 

 tion of hydrochloric acid and its action is almost instantaneous. Even if the 

 acid is injected after the venom, provided the venom was promptly followed 

 by the acid injection, no haemorrhage is produced- in the peritoneum of 

 guinea-pigs and consequently no fatality results, even from a large quantity 

 of the venom. I was able to confirm his observation to a large extent. 



Flexner and Noguchi had shown, prior to Morgenroth, that the hasmor- 

 rhagin is very sensitive to acid treatment. They utilize this mode of modifi- 

 cation of haemorrhagin for immunization, the disagreeable local effects having 

 been easily eliminated without impairing the property of venom to produce anti- 

 haemorrhagin in the immunized animals. They considered this phenomenon 

 as an example of toxoid formation of haemorrhagin in Ehrlich's sense. It is 

 very interesting also to notice that a weak solution of trichloride of iodine 

 produces a similar modification of the haemorrhagin and can be used for 

 an easy accomplishment of crotalus immunization. Flexner and Noguchi 

 have not made investigations as to the comparative merits of the unmodified 

 and modified venoms in producing antivenins, but, at all events, as the degree 

 of immunity reaches a certain point, the unmodified venom may gradually 

 be substituted, should the modified venom prove in any respect inferior to 

 the unmodified in producing strong antivenin. 



Lachesis flavoviridis s. Trimeresurus riukiuanus contains chiefly haemor- 

 rhagin, while haemolysin, agglutinin, . and neurotoxin are present only in 

 trifling quantities. According to Ishizaka, the haemorrhagin of this venom 

 becomes inactive when shaken with chloroform, or acted upon by hydrogen 

 sulphite, ferric chloride, and acetic or hydrochloric acid. 



The removal of haemorrhagin by heating to 73 C. diminished its toxicity 

 to one twenty-seventh, while chloroform treatment diminished it to one- 

 seventeenth of its original strength. On the other hand, haemolytic and neuro- 

 toxic effects are not reduced by these treatments. 



Ishizaka also found, as Flexner and Noguchi did, that tryptic digestion of 

 the venom completely destroys its toxicity. The modified haemorrhagin 

 (chloroform, SH 2 ). of this venom was capable of producing anti-haemorrhagin 

 in the animals by repeated injections — this confirming the toxoid formation 

 of haemorrhagin first described by Flexner and Noguchi. 



The same author made an attempt to remove haemorrhagin by means of 

 endothelial cells of the aorta and richly vasculated organs, but no absorption 

 was observed. 



