TOXIC ACTION OF COMPLEMENTS 79 



(c) With Ox's Complement 



The ox's complement is not a very suitable one to employ 

 in this combination, as the natural serum of the ox has a 

 very powerful haemolytic action in itself, and it is only 

 possible to remove a small proportion of the natural immune- 

 body by contact experiments. Nevertheless, we have found 

 that the dose of ox's complement, along with the immune- 

 body to guinea-pig's corpuscles, is a small one, and there 

 is no doubt that guinea-pig's corpuscles are very sensitive 

 to the zymotoxic action of ox's complement. 



When we come to investigate the combining affinities, 

 we find that multiple doses of immune-body have very 

 little effect on the amount of ox's complement taken up, 

 the amount taken up by means of from four to eight doses, 

 for example, being very little more than that taken up by 

 means of one dose. This may be due to a true want of 

 combining affinity on the part of the complement, or it 

 may be due to the combination being a very loose one. It 

 may be noted, however, that there is practically, in the 

 course of twelve hours, no evidence of dissociation of com- 

 plement after it has really combined. The following will 

 serve as an example : 



Experiment LXXIV. 



1 dose of IB took up 0-04 c.c. of ox's C. 

 4 doses 0-042 



Q 



}> J> 5> J5 - 



The indicator was guinea-pig's corpuscles treated with 

 immune-body, for which the dose of ox's complement was 

 0-02 c.c. 



//. Immune-body to Rabbit's Corpuscles (obtained by injecting 

 the Guinea-pig). 



(a) With Rabbit's Complement 



This case is in many ways analogous to that of the immune- 

 body to guinea-pig's corpuscles along with guinea-pig's 



