UNION OF COMPLEMENT 25 



ON THE NATURE OF THE UNION OF COMPLEMENT THROUGH 

 THE MEDIUM OF AN IMMUNE-BODY 



Having thus found that complement enters into direct 

 combination of firm nature with various cells, bacteria, &c., 

 we have to consider the nature of the combination of 

 complement brought about through the medium of an 

 immune-body. In this connexion there are two chief 

 subjects to be considered, namely, (a) the degree of firm- 

 ness of the union, and (b) the amount of complement which 

 is absorbed in the case of varying amounts of immune- 

 body. A simple experiment demonstrates at once the 

 firmness of the union, and the increased amount of comple- 

 ment fixed, by increasing the amount of immune-body. 

 We take two tubes, A and B, each containing 1 c.c. of 

 suspension of red corpuscles ; to A we add one dose of 

 immune-body, and to B seven doses of immune-body ; 

 to each tube four doses of complement are added. The tubes 

 are placed in an incubator for two hours at 37 C. ; lysis is 

 of course complete in both tubes at the end of that time. 

 1 c.c. of suspension of sensitized corpuscles is added, and 

 the tubes are once more placed in the incubator. The 

 result is that the added corpuscles in tube A become com- 

 pletely lysed, whilst those in tube B are unaffected. This 

 shows that the larger amount of immune-body in tube B 

 has led to the combining of all the complement which was 

 added (four doses). It also shows that the combined 

 complement is not separated by dissociation in the condi- 

 tions of the experiment, otherwise some lysis of the added 

 corpuscles would have occurred. Numerous experiments 

 of similar character have been made, and though it cannot 

 be stated absolutely that no dissociation of complement 

 ever occurs, one can say that even when large amounts 

 of complement have been taken up, the separation of an 



