456 



COLLECTED STUDIES IN IMMUNITY. 



guinea-pig blood-cells, in themselves susceptible to cobra venom 

 alone, is also inhibited by cholesterin. To be sure, rather large quan- 

 tities of the latter are required, but in view of the lecithin character 

 of the substances which functionate as endoactivators, this is to be 

 expected. (See Table XL) 



TABLE XI. 



On the other hand, as already remarked, cholesterin exerts little 

 or no protection against cobra-venom haemolysis when serum com- 

 plement is used for activation. This agrees entirely with the nega- 

 tive findings on the protective action of cholesterin recently reported 

 by Flexner and Noguchi in an interesting paper on the amboceptor, 

 toxoids, and separate constituents of snake venom. 1 



The apparent deviations are probably to be explained merely by 

 the different conditions of the experiments, for, as it appears to 

 us, these authors made their experiments only on unwashed blood- 

 cells or by the addition of serum. In both cases, however, one is 

 dealing with an activation with complement, against which we also 

 failed to detect any marked protection with cholesterin. 



IV. The Quantitative Relations Existing Between Cobra Venom 



and Lecithin. 



So far as the mechanism of cobra-venom-lecithin haemolysis is 

 concerned, we assume that the lecithin acts after the manner of 

 complements, being anchored by certain definite groups of the poison 

 molecule. This has previously been described by Kyes, 1. c. 



Cobra venom and lecithin accordingly combine just like am- 

 boceptor and complement in serum haemolysins, and it was there- 

 fore to be expected that the quantitative relations which exist be- 



1 Flexner and Noguchi, The Constitution of Snake Venom and Snake Sera, 

 Univ of Penna. Med. Bulletin, Vol. XV, No. 9, 1902. 



