662 



COLLECTED STUDIES IN IMMUNITY. 



To 1 cc. 5% ox blood are added 0.0015 cc. rabbit amboceptor, and the 

 mixtures kept at 37 for one hour. Each tube receives decreasing amounts 

 of antiserum, those in series A directly, and those in series B, to the blood- 

 cells separated by centrifuge and freed from the fluid medium in which they 

 had been suspended. The two series therefore contained, in addition to the 

 antiserum: 



Series A. Blood-cells laden with amboceptor, plus free normal ambocep- 

 tors, plus precipitable substance. 



Series B. Only blood-cells laden with amboceptor. 



Both sets of tubes are kept at 37 for two hours, then in the refrigerator 

 over night, and centrifuged the next morning. The sediments are suspended 

 in physiological salt solution to which, for each tube, 1 solvent doses of 

 guinea-pig serum have been added (0.03 cc.). The degree of haemolysis is 

 noted at the end of J and 2 hours. See Table VI. 



TABLE VI. 



A number of points are brought out by this table. In series B we observe 

 that the antiamboceptor has exerted a distinct influence on the antiambo- 

 ceptor l anchored by the cells and freed from other serum constituents. 

 Examining the tubes at the end of half an hour we see that haemolysis has 

 been markedly inhibited. Subsequently, however, this inhibition gradually dis- 

 appears, so that at the end of two hours what little antihsemolytic action is 

 still present is insignificant when compared to the antiamboceptor action at 

 the end of half an hour. This result agrees very well with the assumption that 

 the complement is able, after a time, to dislodge the antiamboceptor. On 

 comparing the results in series B with those in series A, we note that the 



Misprint for amboceptor (?) [Editor.] 



