§ 664.] COBRA POISON. 507 
The Proteroglyphce include most of the poisonous snakes other than 
vipers ; to this order belong :— 
The sea-snakes (Hydrophinae), common in the Indian Ocean and in 
the Pacific. The poison of the Enhydrina bengalensis has been investi¬ 
gated by Leonard Rogers ; he found it less resistant to heat than the 
cobra poison ; its physiological action strongly resembled that of the 
cobra, but since the lethal dose for birds was so small as -05 mgrm. per 
kilo., it appeared to be ten times stronger or more concentrated. 
Fraser and Elliott have also made some observations on the poison 
of Enhydrina valakadien, and found that the dried poison killed cats in 
the proportion of *02 mgrm., rabbits *06 mgrm., and rats -09 mgrm. 
per kilo, of body weight. 
§ 664. The Poison of the Cobra. —The poison excreted from the 
salivary glands of the cobra di capello is one of the most deadly animal 
fluids known. When first ejected, it is an amber-coloured, rather 
syrupy, frothy liquid, of specific gravity 1*046, and of feeble acid 
reaction ; it dries rapidly on exposure to air to a yellow film, which 
readily breaks up into brilliant yellow granules, closely imitating 
crystals. The yellow powder is very acrid and pungent to the nostrils, 
and excites a painful (though transitory) inflammation, if applied to 
the mucous membrane of the eye ; the taste is bitter, and it raises 
little blisters on the tongue. It is perfectly stable, can be heated 
to 100° C. for a short time without decomposition, and preserves its 
activity for an indefinite time. The dried poison as described is perfectly 
soluble in water, and if the water is added in proper proportions, the 
original fluid is without doubt reproduced, the solution usually depositing 
a sediment of epithelial debris, and often containing little white threads. 
The poison has been examined by several chemists, with various 
results. The senior author isolated, in 1876, a crystalline principle as 
follows :—The yellow granules were dissolved in water, the albumen which 
the venom so copiously contains coagulated by alcohol, and separated by 
filtration ; the alcohol was then driven off at a gentle heat, the liquid 
concentrated to a small bulk, and precipitated with basic acetate of 
lead. The precipitate was separated, washed, and decomposed in the 
usual way by SH 2 , and on removing the lead sulphide, crystals having 
toxic properties were obtained. The authors have been unable, through 
want of material, to deal with the suggestion of F. Norris Wolfenden that 
the crystals were those of gypsum, their toxic properties being due to 
adhering impurities. 
Pedler, 1 precipitating the albumen by alcohol, and then to the 
alcoholic solution adding platinic chloride, obtained a semi-crystalline 
precipitate, which from an imperfect combustion he thinks may have 
something like the composition PtCl 4 (C 17 H 25 N 4 0 7 HCl) 2 . 
1 Proc. Roy. Soc., xxvii. 17. 
