250 VENOMS 
(Hoplocephalus, Pseudechis) form a special group, which is richer in 
hæmorrhagin than are those of the CoLuBripÆ of the Old World.! 
On studying, in the case of these various venoms, the action in 
vitro and in vivo of a purely antineurotoxic antivenomous serum, 
such as, for example, that of an animal vaccinated against cobra- 
venom heated to + 75° C., it is found that this serum has a very 
decided effect upon cobra-venom, and likewise upon that of snakes 
belonging to allied species (Naja bungarus, Naja haje), and that its 
action upon the other venoms is less in proportion as they contain 
less neurotoxin. It prevents hemolysis tn vitro, and suppresses the 
effects of intoxication on the nervous system, but does not modify 
in any way the phenomena of coagulation or of proteolysis. 
If this serum be made to act in vitro on those VIPERINE 
venoms that, when heatel to + 75° C. and deprived of their 
hemorrhagin, remain neurotoxic, like the venom of the common 
viper, it is found that it renders them entirely innocuous. There- 
fore, in the case of all species of poisonous snakes, and perhaps 
also in that of other poisonous animals (such as scorpions), it 
appears that the newrotoric substance is one and the same, and 
always neutralisable by an antinewrotoxic serum like that of 
animals vaccinated against cobra-venom. 
Neurotoxin being the essentially active substance in venoms, and 
that to which the dangerous properties of poisonous snakes, as 
regards man and domestic animals, are especially due, it is the 
effects of this that it is most necessary to prevent. Consequently, 
1 Cf. papers by George Lamb, Scientific Memoirs by Officers of the Medical 
and Sanitary Departments of the Government of India, New Series, Nos. 1, 3, 
4, 5, 7, 10, 16; L. Rogers, Proceedings of the Royal Society of London, vol. 
Ixxii., and Lancet, February 6, 1904; C. J. Martin, Intercolonial Medical 
Journal of Australasia, August 20, 1897, April 20, 1898; Dr. Hunter, Lancet, 
January 2, 1904; Dr. Tidswell, Australasian Medical Gazette, April 21, 1902; 
A. Calmette, Comptes rendus de l'Académie des Sciences, May 2, 1904; Dr. 
Vital Brazil, “ Contribution a l'étude de Vintoxication ophidienne ” (separately 
published pamphlet), Paris, 1905; G. Bill, Intercolonial Medical Journal of 
Australasia, July 20, 1902, 
