NEUROTOXINS OF SNAKE VENOM 149 
Calmette and Massol ! confirmed the finding of Morgenroth that the neuro- 
toxin can be separated from the neutral mixture of venom and antivenin 
by means of a weak solution of hydrochloric acid and by almost any acid, 
mineral or organic. More striking is their finding that the neurotoxic principle 
of cobra venom can be extracted from the mixture of venom and antivenin by 
means of so per cent alcohol, in which antivenin is insoluble. In fact, Cal- 
mette and Massol found that the neurotoxin can be extracted from venom 
solution by alcohol as high as 86 per cent. They employed findings to show 
the reversible nature of the compound of venom and antivenin, and I shall 
later return to this subject in a proper place, when discussing the properties 
of antivenin. 
The neurotoxic principles of snake venom possess specific affinity toward 
the nerve tissues. Flexner and Noguchi showed that if a few minimal lethal 
doses of ancistrodon venom be mixed with the mashed brain-substance of 
susceptible animals the greater portion of the toxicity disappears from the 
fluid obtained by centrifugalization of such mixture. This fixation of the 
neurotoxic principles is very pronounced when the emulsion of brain sub- 
stances is employed, but none or only slightly when the emulsions of other 
organs are used. Myers, who made a similar experiment before these 
authors, failed to obtain a positive result. 
Calmette lately also found that there is absorption of toxic principles of 
cobra venom by the brain emulsion. 
After the work of Kyes cholesterin is known to possess a certain antihzemo- 
lytic property against native cobra venom or lecithid, and the isolation by 
Faust of a sapotoxin from the cobra venom, and the discovery by Ransom of 
the antisaponic property of cholesterin, the phenomenon of Flexner and 
Noguchi, the fixation of the neurotoxin by the nerve tissue, may have to be 
viewed in a different light. It remains to be seen whether the ophiotoxin of 
Faust is neutralized by cholesterin or not. In the case of positive outcome, 
the phenomenon of fixation may simply be due to the action of cholesterin in 
the brain emulsion. The fixation of tetanus toxin by the brain emulsion, as 
discovered by Wassermann and Takaki, is no longer a specific phenomenon, 
but is considered to-day to be the action of cholesterin, protagon, cerebrin, 
etc. In this regard Noguchi demonstrated that tetanolysin is neutralized by 
cholesterin, while Landsteiner showed that tetanus toxin is inactivated by 
protagon. Again, it may be recalled here that Fraser discovered long ago 
that the bile has antivenomous property against cobra venom. 
One of the most important and interesting questions concerning the neuro- 
toxins of snake venoms, both from the practical and the theoretical points 
of view, is the identity of these principles. It is no wonder that none of 
the earlier investigators raised this question, because symptomatology does 
not reveal such delicate differences. All investigations of pre-antitoxin age 
passed it as granted that the neurotoxic effects of various venoms are pro- 

1 Calmette and Massol. Relations entre le venin de cobra et son antitoxine. Ann. Inst. Pasteur, 1907, 
XXI, ‘929. 
