Till-: riiYsioTj^ay of r(JisoxiXG 197 



a nearly constant mean sensitivit3^ The corpuscles of the ox, 

 goat, sheep, and rahhit are less sensitive. Those of man, the 

 guinea-pig, and the rat, on the contrary, are more so. 



On experimenting with trashed corpuscles, it is found that 

 venom alone is incapable of dissolving them. In order that dis- 

 solution may take place, we are obliged to add to the mixture 

 either a small quantity of normal horse-serum, preferably heated, 

 and, consequently, deprived of alexin (Calmette), or i c.c. of a 1 in 

 10,000 solution of lecithin in physiological saline water (P. Kyes). 



Venom, therefore, is capable of hsemolysing red corpuscles only 

 when it is quickened, either by heated normal serum, or by lecithin. 

 The solution of lecithin employed for this purpose should be pre- 

 pared by dissolving 1 gramme of lecithin in 100 grammes of pure 

 methylic alcohol. Taking 1 c.c. of this dilution we add it to 9 c.c. 

 of 8 in 1,000 saline solution, and make a second dilution of 1 c.c. of 

 the foregoing mixture in 9 c.c. of saline water. This latter dilution 

 of 1 in 10,000 is utilised as the reagent. 



Let us now see how tbe serum or lecithin acts. It has been 

 shown by P. Kyes that with either of these substances the mecha- 

 nism of the haemolytic action is the same, for the serum quickens 

 the venom only through the agency of the free lecithin it contains. 

 The lecithin takes part in the reaction by combining with the 

 venom to form a haemolysing lecithide more resistant to heat than 

 its two components, for it may be heated for several hours at a 

 temperature of 100° C, without the loss of any of its properties. 



When venom is brought into contact with certain kinds of 

 highly sensitive red corpuscles, those of the rat for example, these 

 corpuscles, although washed and freed from serum, may undergo 

 hsemolysis. This result is due to the fact that these corpuscles 

 contain sufiicient quantities of lecithin, which becomes liberated 

 from their protoplasm and, uniting with the venom, constitutes 

 the active lecithide. 



It was already known that lecithin is capable of combining 

 wdth various albuminoid matters and with sugars to form lecithides. 



