SPECIFICITY AND THERAPEUTIC VALUES OF ANTIVENINS 235 
Stephens‘ then brought out the very important fact that the hemolytic 
principles of various kinds of venoms are not identical as far as their affinity 
to Calmette’s antivenin is concerned. He showed that, while the hemolytic 
toxin of cobra venom is easily neutralized by this antivenin, those of daboia 
or crotalus venoms remain almost unneutralized by the same. He concludes: 
(1) That antitoxic sera can act upon toxins other than, but allied to, those 
used in the preparation of the serum. 
(2) That the hemolytic constituents of snake toxins, and hence snake 
toxins as a class, are not identical. 
(3) That against a minimal lethal dose of daboia venom o.5 c.c. of Cal- 
mette’s antivenin has very little action. 
(4) That the antihemolytic properties of antivenomous sera must be 
increased, in order to afford any efficient protective serum, e.g., against 
pseudechis toxin or daboia toxin. 
Myers ” found that cobra venom contained two principles, which he terms 
cobralysin and cobranervin. The cobralysin, which is the hemolytic sub- 
stance, is destroyed by heat, the cobranervin remaining unaltered. Cobralysin 
can be neutralized by antivenin, the cobranervin remaining free. It is only 
in minimal fatal dose that the neutralization of both goes together. With 
multiples of the minimal fatal dose, a non-hemolytic mixture of venom and 
antivenin may rapidly kill a guinea-pig. 
The susceptibility of the erythrocytes to the action of the cobralysin in vitro 
bears no relationship to the susceptibility of the animal to subcutaneous 
toxication by the venom. In the lethal properties of the venom the cobra- 
lysin plays an insignificant part. Toxoids rapidly form in dilute solutions of 
venom, these toxoids seeming to be specific. 
McFarland immunized horses to unmodified crotalus venom mixed with 
several other kinds of venoms and obtained an antivenin which was equally 
effective against the venoms of Crotalus adamanteus, Ancistrodon contortrix, 
Naja tripudians, and Cerastes. It was able to counteract only the neurotoxins, 
but not local irritative principles. This experiment neither negatives nor 
proves the question of the specificity of antivenins, as it was prepared with 
mixed venoms. 
On the other hand, Flexner and Noguchi* produced an antivenin for cro- 
talus venom by injecting venom modified by hydrochloric acid or trichloride 
of iodine and found that the antivenin had a neutralizing action upon the 
hemorrhagins; also that Calmette’s antivenin has only a feeble protective 
action against crotalus venom, as it has no anti-hemorrhagic power. 
In 1904 Jacoby made a series of experiments with the hamolysin-free 
cobra venom in regard to its relation to the native unmodified venom. ‘The 
material which he employed was the aqueous solution of cobra venom, from 
1Stephens. On the hemolytic action of snake-toxin and snake sera. Jour. of Path. and Bact.» 
1899-1900, VI, 273. 
2 Myers. On the interaction of toxin and antitoxin; illustrated by the reaction between cobralysin 
and its antitoxin. Jour. of Path. and Bact., 1899-1900, 415. 
3 Flexner and Noguchi. Production and properties of anti-crotalus venin. Jour. of Med. Research, 
1904, n. s., VI, 363. 
