SUBSTANCES WHICH ACTIVATE COBRA VENOM. 455 



it impossible to demonstrate the existence of the latter by means 

 of cobra-venom haemolysis. 1 



Having thus learned that cholesterin exerts a marked inhibiting 

 effect on the action of lecithin we shall probably not err if we 

 assume that part of the serum protection is due to the choles- 

 terin present in the sera. One thing which agrees perfectly with 

 this assumption is the fact that often this protective action is still 

 present after heating the serum to 100 C. 



The marked inhibition of haemolysis on the addition of choles- 

 terin, an inhibition which applies also to the haemolysis produced 

 by lecithin alone when in large quantities, points to an interesting 

 antagonism between lecithin and cholesterin, to which a few words 

 may be devoted. 2 In this case the cholesterin probably has a rela- 

 tion to lecithin which is similar to that of saponin in Ransom's well- 

 known experiments. 3 In both cases we seem to be dealing with the 

 effect of a kind of solvent affinity between cholesterin on the one 

 hand and lecithin and saponin on the other, by means of which 

 affinity the presence of cholesterin within the blood-cells gives rise 

 to toxic action, and outside of the erythrocytes exerts a protective 

 action. It is possible that the protection observed by us in haemolytic 

 test-tube experiments with cholesterin is in some way connected 

 with the protective action of cholesterin against snake venom in the 

 animal body described by Phisalix. 4 Another fact may be men- 

 tioned in this connection, namely, that the haemolysis of washed 



1 On the other hand the specific protection exerted by Calmette's snake- 

 venom immune serum is not an antilecithin effect, but, as was to be expected, 

 one depending on the action of the antibody produced by immunization (anti- 

 amboceptors) on the amboceptors of snake venom. When varying amounts 

 of lecithin were employed the protective action of Calmette's serum remained 

 constant, always neutralizing the same amount of cobra venom 



8 We may add that, like Noguchi (The Antihsemolytic Action of Blood Sera, 

 Milk, and Cholesterin upon Agaricin, Saponin, and Tetanolysin, etc., Univ. of 

 Penna. Med. Bulletin, Vol. XV, No. 9, 1902), we observed a very marked choles- 

 terin protection against the action of tetanolysin. (0.00025 cc. of our stock 

 solution, which certainly contains not more than 1% cholesterin, protects against 

 the complete solvent dose of tetanolysin (0.05 cc.).) On the other hand, choles- 

 terin is absolutely without effect on the hsemolyses due to staphytolysin and 

 arachnolysin. In connection with this we might mention the fact so inter- 

 esting biologically, that even so indifferent a substance as neutral olive-oil dis- 

 solves the red blood-cells. This haemolysis is likewise inhibited by cholesterin. 



3 Ransom, Saponm und sein Gegengift. Deut. med. Wochensch. 1901. 



4 Phisalix. Compt. rend, de la Soc de Biologic, 1897. 



