308 IMMUNO-CATALYSIS 



theria antitoxin or tetanus antitoxin, possessed no such power. A guinea 

 pig weighing from 250 to 350 g. succumbed in five to eight hours after 

 receiving 0.1 mg. of cobra venom. The hemolytic action of this 

 quantity of poison, as shown above, was neutralized by 0.1 ml. of im- 

 mune serum, and such a neutral mixture was never found to be fatal 

 to the animal, but if the hemolytic action was incompletely neutralized 

 the animal might either survive or die. These findings suggested a 

 direct relationship between the antihemolytic and the in vivo protec- 

 tive power of the immune serum; they found, however, that when 

 higher amounts of venom were treated with the equivalent amount of 

 antiserum the protection was not always obtainable, which they 

 believed was due to the presence of other non-neutralized toxic factors 

 in the venom. 



a. Discovery of Hemolytic Lecithinase and Its Neutralization by 

 Antivenin. Later studies showed that the hemolytic action of snake 

 venom was due to the lipolytic action of venom lecithinase on the 

 lecithin of red blood cells, resulting in the production of hemolytic 

 lysolecithin and lysocephalin. The lecithinase activity was found to 

 be completely neutralizable by antivenomous serum; that is, the 

 enzymatic formation of hemolytic lysolecithin and lysocephalin was 

 prevented by antivenom. In addition to the antinecrotic, anticlotting 

 and antiproteolytic properties, the antivenom must also possess anti- 

 lecithinase activity in order to account for its protective property in 

 vivo. The discovery of lecithinase progressed as follows. Flexner and 

 Noguchi (1902) at the University of Pennsylvania discovered that in 

 no instance were washed Mood cor-puscles hemolyzed by venom. If the 

 separated serum was restored to each of the several kinds of blood 

 corpuscles treated with venom, lysis took place. This observation was 

 the beginning of a chain of discoveries which established the fact that 

 the hemolysis of red blood cells by snake venom was mediated by 

 the enzyme lecithinase. Two years later Kyes (1903, 1904), of the 

 University of Chicago, working in Ehrlich's laboratory, found that if 

 cobra venom is brought into contact with lecithin a hemolytic sub- 

 stance is produced. He also showed that anti-cobra venom horse serum 

 neutralizes the action of numerous snake venoms on lecithin, ap- 

 parently preventing the formation of the hemolytic lecithin deriva- 

 tive. 



Von Dungern and Coca (1908) reported that the hemolytic deriva- 



