THE BIO-CHEMISTRY OF ANIMALS AND PLANTS in 



constitution such as the alkaloids (nicotine, morphine, etc.), or 

 against metallic poisons (arsenic, sublimate, phosphorus, etc.), 

 have so far not been successful. 



In connection with phyto-toxins, we may shortly discuss 

 from the chemical point of view one of the many animal toxins, 

 namely that contained in the poison fangs of certain snakes. 

 According to Weir Mitchell and Reichert these toxins are also 

 of a protein nature, being mixtures of a globulin and an 

 albumose. They have recently aroused great interest through 

 their relation to bacterial toxins and the problems of immunity. 

 Their action may also be investigated outside the body by their 

 hasmolytic properties, i.e. their effect of producing solution of 

 red blood corpuscles. The venom which has been studied most 

 thoroughly in this direction is that of the Indian cobra, and the 

 results promise to be of great importance in widening our know- 

 ledge of a class of substances about the functions of which, in 

 the body, we have been up to the present absolutely in the dark. 

 The substances referred to are represented by cholesterin, 

 lecithin, and allied substances, for which, following the proposal 

 of Overton, the term " Lipoids " is now generally accepted. 



Toxolecithides. — The experiments of Flexner and Noguchi 

 were the starting-point of these observations. They found 

 that the hasmolytic action of cobra venom on red blood 

 corpuscles can be prevented by complete removal of the 

 adhering serum by washing with physiological salt solution. 

 On adding serum or blood to the washed blood corpuscles in 

 presence of cobra poison, haemolysis takes place. Kyes was 

 able to explain this striking fact. Evidently serum contains an 

 activating substance, and it was shown that this substance is 

 heat resisting. Kyes further showed that the activator is not 

 only soluble in alcohol but also in ether, and he finally 

 identified it as lecithin. He was able to prove by purely 

 chemical methods that cobra venom combines with lecithin to 

 form the new hemolytic compound, which he actually isolated. 

 Most suggestive in this connection is the behaviour of cholesterin. 

 This substance has the property of preventing or counteracting 

 the activating action of lecithin on cobra venom. This an- 

 tagonism between lecithin and cholesterin points to a chemico- 

 physical relationship between the two substances. In order 

 to exercise this function the hydroxyl group as well as the 

 double linkage of carbon atoms in derivatives of cholesterin 



