664 



COLLECTED STUDIES IN IMMUNITY. 



plete haemolysis, we did, to be sure, observe a slight loss of comple- 

 ment, despite the presence of antiamboceptor. We believe that this 

 is caused by the presence of a very small amount of precipitate. The 

 important fact, however, is that we could demonstrate plenty of 

 free complement, although there was no haemolysis. 1 A brief de- 

 scription of such an experiment follows: 



To 0.125 cc. antiserum are added 0.0015 cc. rabbit amboceptor, 

 and the mixtures kept at room temperature for 45 minutes. Ox 

 blood is added, and the mixtures kept at 37 for one hour. After 

 centrifuging, the sediments are mixed with guinea-pig serum, as 

 follows : 



1. 0.075 cc. = l^ complete solvent doses. 



2. 0.1 cc. = 2 solvent doses. 



3. 0.2 cc. = 4 solvent doses. 



4. 0.3 cc. = 6 solvent doses. 



The tubes are kept at 37 for two hours, then over night in the 

 ice chest. The following day the supernatant fluids are carefully 

 poured off and tested for complement by adding the sediments 

 obtained from 1 cc. 5% ox blood plus 0.0015 cc. rabbit amboceptor. 

 The result is shown in Table VII. 



TABLE VII. 



Although as indicated in the first column of the table, there is a 

 moderate diminution of complement, we note that despite a plentiful 

 amount of complement, haemolysis does not occur. The reason for 



1 We see, therefore, that the ability of the complement to dislodge anchored 

 antiamboceptor (if such a power is at all possessed by the complement) does 

 not always manifest itself. 



