Il8 LECTURES ON IMMUNITY 



As illustrations may be given the haemolytic action of 

 the snake-venoms of the water-moccasin (Amis trod on 

 piscivorus), and cobra (Naja tripudians) and of staphy- 

 lolysin, produced by staphylococcus. 



The snake-poisons were tested on horse-blood, the 

 staphylolysin on rabbit-blood. Probably the observed 

 phenomenon is of complex nature. A maximum effect 

 might result if the haemolytic agent were decomposed 

 with increasing temperature. At low temperatures, then, 

 where the decomposition is insignificant, the poisons be- 

 have normally, the velocity of reaction increases with tem- 

 perature. If then at higher temperatures the decompo- 

 sition or dissociation of the^ poisonous substance increases 

 more rapidly with temperature than the velocity of the 

 real reaction, then the quantity of poison necessary for a 

 given haemolytic effect (in a given time) must increase with 

 temperature. A closer investigation of these complicated 

 phenomena will be necessary to show whether an explana- 

 tion analogous to that sketched above may be assumed. 



The phenomena studied above in this chapter are, gen- 

 erally speaking, due as well to velocities of reaction as to 

 real chemical equilibria. These prevail the more, the 

 longer the time of reaction and the higher the tempera- 

 ture. The observations have great importance because 

 they correspond to the method of working actually used, 

 which is determined by the nature of the material em- 

 ployed. Hence their discussion is useful for the compre- 

 hension of the results of the ordinary method of working, 

 and for the arrangement of similar experiments. There- 

 fore I have discussed them in a rather detailed manner, 

 although their theoretical meaning is not very simple. 



