COMPLEMENT AS AGGLUTININ 87 



immune-body and 0-2-0-3 c.c. of ox's serum (complement). 

 The addition of larger amounts of immune-body or of 

 complement has some effect in increasing the agglutination, 

 but only to a trifling extent. It occurred to us that the 

 agglutination might be due to the imperfect lytic action of 

 complement, resulting in the production of an adhesiveness 

 of the corpuscles, but we have found that the agglutination 

 by the complement also occurs when the lysis is complete. 

 If we take some suspension of ox's corpuscles, add several 

 doses (say eight) of immune-body and produce complete lysis 

 by a single dose of guinea-pig's complement, we get a clear 

 fluid, in which nothing can be seen by the naked eye, and in 

 which on microscopic examination the stromata or shadows 

 are seen to be uniformly distributed. If then to such a fluid 

 we add 0-2 c.c. of ox's serum and place the mixture in the 

 incubator for a short time, flocculi appear which are found to 

 be composed of agglutinated stromata. Another example may 

 be given. We have stated (p. 73) that it is not possible to 

 produce complete lysis of ox's corpuscles by ox's comple- 

 ment acting along with the immune-body mentioned, and 

 we have found this always to be the case when the immune- 

 body and the complement are added at the same time. 

 Since making that statement, however, we have observed 

 that if the immune-body is added some time say an hour 

 previous to the addition of the complement, then as a rule 

 complete lysis does occur on the addition of the latter, and 

 in such a case there is marked agglutination of the stromata. 

 From these facts it is evident that the agglutination does 

 not depend upon an imperfect lysis. 



Another point worthy of note is that the agglutination 

 passes off after some time, usually in five or six hours, at 

 the room temperature. When this occurs the agglutination 

 can be restored on the addition of more complement, whilst 

 additional immune-body is practically without effect. As a 

 rule this second agglutination is not quite so marked as the 



