MECHANISM OF THE ACTION OF ANTIAMBOCEPTORS. 573 



(0.25 cc.). After centrifuging, decreasing amounts of inactivated 

 normal rabbit serum are added to the sediments, and the mixtures 

 again centrifuged. The blood-cells thus separated are suspended 

 in 0.1 cc. salt solution containing 0.1 cc. guinea-pig serum. The result 

 is shown in the following table: 



TABLE III. 



This table, therefore, shows that sensitized blood-cells which have 

 been treated with an excess of antiamboceptor and then freed from 

 all free serum constituents by centrifuging can be deprived of a con- 

 siderable portion 1 of the antiserum constituent b by subsequently 

 digesting them with small amounts of normal rabbit serum, thus 

 again allowing the antiamboceptor action to become manifest. It 

 is permissible, therefore, to assume that the antiamboceptor a had 

 been bound and that the union had remained a loose one owing to 

 the occupation of group /9, Owing to the looseness of the union a 

 and a the complement was not prevented from combining with the 

 amboceptor. 



We have gone into the analysis of this case with such detail because 

 it again shows how complicated is the mechanism of amboceptors 

 and yet how easy it is by means of the amboceptor theory to bring 

 these apparently paradoxical phenomena into harmony. In this case 

 we are certainly dealing with extraordinarily complex conditions, 

 conditions in which Bordet's rudimentary sensitization theory is 

 entirely helpless. 



The phenomenon just described possesses a certain practical 

 significance in so far as it could easily lead to the erroneous assump- 



1 It is likely that the reason why the inhibiting action cannot be entirely 

 brought out by this means is that the union of b, once it is bound, rapidly be- 

 comes firm, thus permitting only a partial dissolution by means of free /?. In 

 any event this experiment clearly exhibits, as already stated, exactly the re- 

 verse behavior of that shown by Bordet's. 



