184 



COLLECTED STUDIES IN IMMUNITY. 



In two combinations (Cases I and II) the separation of the two 

 components was effected without any trouble. The following pro- 

 tocol will also show the technique of the experiment. 



Negative case I of Buchner. 0.5 cc. sheep serum is still just 

 able to completely dissolve guinea-pig blood. To each 1 cc. of a 

 5% guinea-pig blood suspension varying amounts of active sheep 

 serum are added and the volume of fluid made up to 2 cc. with physio- 

 logical salt solution. Two parallel series like this are kept at C. 

 for two hours and then centrifuged. The clear decanted fluids from 

 the one series are allowed to act each on the sediment of 1 cc. native 

 5% guinea-pig blood; the fluids from the other series, each on the 

 sediment of 1 cc. 5% guinea-pig blood, which had previously been 

 treated with the same varying amounts of inactive sheep serum. 

 The hsemolytic action of the decanted fluids is shown by Table I. 



TABLE I. 

 ABSORPTION OF SHEEP SERUM BY GUINEA-PIG BLOOD AT C. 



Buchner's second negative case deals with the combination sheep 

 blood and rabbit serum. In the following experiment, entirely ana- 

 logous to the preceding, the complete solvent dose of rabbit serum 

 for sheep blood was 0.2 cc. See Table II. 



These experiments, which are confirmed by numerous parallel 

 experiments, show that in these two cases, as a matter of fact, hcemolysis 

 depends on the presence of two substances. One of these, thermostable, 

 is bound by the blood-cells at 0C., the other, thermolabile, is left 

 behind at this temperature. The latter, however, is only then able 

 to effect haemolysis when it acts on blood-cells which have previously 

 anchored the thermostable substance, the amboceptor. 



A comparison of Tables I and II also shows how much the 

 combining relations between amboceptor and blood-cell on the one 



