CONSTITUTION OF IMMUNE-BODY 21 



explanation, to which further reference is made below 

 (p. 113). 



In favour of the view that complement ultimately unites 

 with the cell receptors is the fact that immune-body can be 

 dissociated after saturation with complement. The pro- 

 gressive character of the lysis which may occur when there 

 is a sub-haemolytic dose of separable immune-body as con- 

 trasted with what is seen in the case of a sub-haemolytic dose 

 of fixed complement, points in the same direction. The 

 matter is fully discussed below (p. 37), but we may here 

 state that in view of all the results obtained, we believe that 

 immune-body which has led to the union of complement 

 can be in part recovered, while the complement cannot, owing 

 to its having become firmly united to the cell receptors. 

 Although we have stated that direct union of immune- 

 body and complement cannot be regarded as having been 

 demonstrated, we have, on the other hand, direct evidence 

 that a certain amount of complement combines directly 

 with receptors, e.g. those of tissue cells, bacteria, and even 

 with heated red blood-corpuscles (p. 24). According to the 

 view that the immune-body acts as a sensitizer, this might be 

 due to its producing in other receptors affinity for comple- 

 ment, or to its increasing the affinity of the molecules already 

 possessing it in some degree. The former would appear 

 to be the more probable, in view of the firmness of the 

 direct union of complement with tissue cells. It is further 

 to be noted, that although differences in the combining 

 groups of complements from the same animal can be made 

 out, there is certainly nothing like the specific relationships 

 which obtain in the case of the cytophile group of immune- 

 bodies. The supposed specific properties of complements of 

 different animals as judged by their anti-complements has 

 now been shown to depend in great part at least on the phe- 

 nomena of deviation of complement described below (p. 133). 

 We have also found that complements from different animals 



