COLLECTED STUDIES IN IMMUNITY. 



each specimen, which was then kept on a water-bath at 38 C. for 

 one hour, after which the mixtures were centrifuged. The blood- 

 cell sediment was again suspended in salt solution and 0.15 cc. guinea- 

 pig serum added as complement. The solution which then ensued 

 was a measure for the bound amboceptor, or for the deflection by the 

 antiamboceptor. Control tests were made with 0.3 cc. normal in- 

 active goat serum in parallel experiments. 



TABLE III. 



A. INHIBITION OF THE AMBOCEPTOR OF THE RABBIT 

 TREATED WITH GOAT SERUM. 



B. INHIBITION OF THE AMBOCEPTOR OF THE RABBIT 

 TREATED WITH GOAT BLOOD. 



The antiamboceptor is thus seen to offer exactly the same pro- 

 tection against the amboceptors obtained as a result of goat-blood 

 injections and those resulting from goat-serum injections, whereby 

 their identity is demonstrated. 



The presence of free receptors in the urine and serum leads to the 

 conclusion that an active receptor metabolism exists in the organism 

 of the goat; in other words, that receptors are constantly reaching 

 the serum from the cells and are then excreted by the kidney. 

 Whether one is here dealing with decomposition products or with 

 the products of some secretion or other cannot be determined. The 



