106 PROPERTIES OF ILEMOLYTIC SERA 



kept out of combination 0-03 c.c. of C. (The test for uncom- 

 bined complement was ox's corpuscles treated with immune- 

 body.) 



It is interesting to note that in a similar experiment made 

 at the same time with ox's corpuscles treated with four 

 doses of immune-body the amount of complement kept out 

 by 0-2 c.c. of anti-immune-body was the same as in the case 

 of guinea-pig's corpuscles, i. e. 0-03 c.c. of complement, as 

 tested with corpuscles treated with immune-body. In other 

 words, apparently the same amount of anti-immune-body 

 had been taken up by the two kinds of corpuscles treated 

 with their corresponding immune-body. 



ACTION OF ANTI-IMMUNE-BODY ON NATURAL IMMUNE-BODIES 



We have investigated this in the case of the anti-immune- 

 body obtained by injecting the rabbit with guinea-pig's 

 serum the anti-immune-body thus neutralizing the immune- 

 bodies derived from the guinea-pig. The normal serum of 

 the guinea-pig has a varying degree of haemolytic action on 

 both rabbit's and ox's corpuscles, and this, as was shown by 

 Ehrlich, is due to the combined action of natural immune- 

 bodies with complement. By placing the corpuscles 

 (rabbit's or ox's) in contact with the guinea-pig's serum at 

 C. a certain proportion of immune-body enters into 

 combination, as is shown by the fact that when the corpuscles 

 are washed in salt solution and complement is added a certain 

 amount of lysis takes place. The method of testing the 

 action of anti-immune-body is thus the following. The 

 corpuscles are placed in the serum of a normal guinea-pig 

 for an hour at C. and are then washed free of serum ; 

 they have thus taken up natural immune-body from guinea- 

 pig's serum. They are then divided into two sets, to one 

 of which is added 0-2 c.c. of anti-immune-body from the 

 rabbit, and to the other, as a control, 0-2 c.c. of rabbit's 



