20 Prof. Pedler on Cobra Poison. [Jan. 17, 



Carbon 



Hydrogen 



Nitrogen . . ........ 



Oxygen and sulphur 



52-87 

 751 

 18-29 

 21-33 



100-00 



The composition of crude cobra poison then approaches rather 

 closely to the known composition of the various kinds of albumin, but 

 the amount of nitrogen in the virus is rather in excess of that con- 

 tained in egg albumin. 



On testing the cobra poison qualitatively, I found that it contained 

 a considerable proportion of a substance which gave all the tests of 

 ordinary animal albumin,* and the amount of this substance was 

 estimated by precipitation with strong alcohol, 0*5403 gram of fresh 

 cobra virus treated in this way gave '0935 gram dry albumin, and 

 '0584 gram of a substance, which was gummy and amorphous in 

 appearance. The albumin on testing was found to be slightly poison- 

 ous, and from its physiological action I concluded that it could not 

 contain more than from one-fiftieth to one- hundredth part its weight of 

 the poisonous principle. The portion soluble in alcohol was excessively 

 poisonons. It appears, then, that in the poison obtained from the 

 cobra there is about 17*3 per cent, of albuminous matter, and 10*9 per 

 cent, of poisonous matter only, or that about 60 per cent, of the solid 

 cobra poison is of an albuminous nature, and only 40 per cent, at the 

 most is pare poison. I have endeavoured, by the use of solvents, both 

 chemical and mechanical, to separate out some crystallizable principle 

 from the poison ; but although I have used a great variety of liquids, 

 I have not yet succeeded in obtaining anything but indications of 

 crystallizable matter, and 1 have now given up all hope of separating 

 any distinct principle from the poison by this method. Dialysis through 

 parchment paper was tried, in the hope of separating some principle, 

 and about half a gram of the solid poison, dissolved in water, was 

 allowed to dialyse for five days ; at the end of that time the liquid from 

 the interior of the dialyser, when evaporated, gave an amorphous 

 gummy mass, which had all the physiological properties of cobra 

 poison ; the liquid, outside the dialyser, when evaporated, gave a 

 residue the greatest part of which was like gum, but a few apparent 

 crystals could be detected. This was tested physiologically, and was, 

 if anything, rather more poisonous than the ordinary virus, and I was, 



* Dr. Armstrong (Proc. Roy. Soc, xxi, 363) had already noticed that the liquid 

 poison when kept contains albuminous matter, but the poison that he examined had 

 already begun to undergo decomposition. The chemical composition of the poison, 

 as determined by Dr. Armstrong, shows a much smaller proportion of carbon and 

 nitrogen than that found by me in the fresh poison. As I have mentioned, the 

 poison does not keep well either as a liquid or a solid, hence the disagreement 

 of the results. 



