THE MODE OF ACTION OF COBRA VENOM. 305 



alcoholic extract is evaporated in vacuo and the residue dissolved in 

 an amount of 0.85% salt solution equal to the original amount of 

 serum, a strong activating fluid is obtained. An alcoholic extract of 

 horse serum, when treated in this way, in contrast to the native 

 horse serum heated to 100 C., dissolves goat blood to a high degree 

 (0.1 cc. dissolves completely). The alcohol precipitate must there- 

 fore have contained a substance which inhibits the action of the 

 activator, and we were actually able to demonstrate the existence of 

 this inhibiting substance. If the precipitate is dissolved in salt water, 

 a fluid is obtained which inhibits the hamolysis of goat blood by 

 cobra venom and the activator derived from the alcoholic extract of 

 horse serum. In larger, though unequal, doses it protects ox blood 

 against solution by cobra venom and the activator. Before studying 

 the nature of the inhibition effected by the albuminous precipitate 

 we shall try to discover the nature of the activator. As already said, 

 the residue obtained on evaporating the alcoholic extract was dissolved 

 in salt water. On shaking this solution with ether, we found that 

 the ether had taken up all of the activating substance. This proved 

 that the activator is a substance soluble both in alcohol and ether, 

 and one which has a wide distribution in the sera of animals. Constit- 

 uents of the blood serum which are soluble in ether have long been 

 known to us. Those mainly to be considered are cholesterin, lecithin, 

 fats and fatty acids. After several negative trials with cholesterin 

 we found that lecithin possesses the properties of the activator, since 

 all blood-cells are rapidly dissolved when cobra venom and lecithin 

 are allowed to act on them simultaneously. Not only blood-cells which 

 are insoluble in cobra venom alone, such as goat blood-cells, but also 

 those which are deprived of endocomplements when treated with 

 strong solutions of poison (see II, Endocomplements) are promptly 

 dissolved by the lecithin. Our solution of lecithin l was made in the 



1 The lecithin employed by us was derived from yolk of egg and obtained 

 from E. Merck, Darmstadt. It was a neutral mass of salve-like consistency, 

 which was entirely precipitated from its ethereal solution by aceton (Altmann- 

 Henriquez). Even when thus purified it manifested the activating power 

 unchanged. We reserve for further study our experiments with the pure lecithin 

 prepared after the method of P. Bergell (Ber. der deutsch. chem. Gesellschaft, 

 Jahrg. 33, 1900, page 2584) and with the homologues of this body. A specimen 

 of lecithin obtained from J. D. Riedel, Berlin, corresponded exactly in its activity 

 to Merck's lecithin. Cerebrin and Protagon, obtained through the courtesy of 

 Prof. Kossei of Heidelberg, possess no activating power. 



