THE PHYSIOLOGY OF POISONING 197 
a nearly constant mean sensitivity. The corpuscles of the ox, 
goat, sheep, and rabbit are less sensitive. Those of man, the 
guinea-pig, and the rat, on the contrary, are more so. 
On experimenting with washed 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 $ c.c. of a 1 in 
10,000 solution of lecithin in physiological saline water (P. Kyes). 
Venom, therefore, is capable of hæmolysing red corpuscles only 
when if 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 the serum or lecithin acts. It has been 
shown by P. Kyes that with either of these substances the mecha- 
nism of the hemolytic 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 hæmolysing 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 
hemolysis. This result is due to the fact that these corpuscles 
contain sufficient 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 
with various albuminoid matters and with sugars to form lecithides. 
