THE PHENOMENA OF ADSORPTION. 445 



The interpretation of Borclet and Gay, on the contrary, is the 

 following : 



The contact with the corpuscles has deprived the bovine serum of 

 its amboceptor; this amboceptor, however, may be replaced by the 

 sensitizer in horse serum, which latter serum also furnishes the 

 alexin. Under these conditions the bovine serum, which still re- 

 mains necessary for hemolysis, acts only on account of the peculiar 

 substance which it possesses, which, as we have just seen, is neither 

 amboceptor nor alexin, but endowed with the peculiar characteristic 

 of allowing horse alexin to produce hemolysis. 



We may, for the sake of clearness, explain this idea somewhat 

 more fully before recalling the experiments which proved its 

 exactness. This particular substance in bovine serum which resists 

 heating to 56 degrees and which for simplicity Bordet and Gay 

 called "bovine colloidal substance" does not react with normal 

 corpuscles; it unites only with corpuscles that have been laden both 

 with amboceptor and alexin. 



This union or adsorption of the particular substance in question 

 by sensitized and alexinized corpuscles is accompanied by visible 

 manifestations; the corpuscles on uniting with this substance are 

 energetically agglutinated and become, with certain exceptions 

 which we shall later mention, more apt to hemolyze. This phe- 

 nomenon of agglutination of the corpuscles into large clumps in 

 Ehrlich and Sachs' experiment, although extremely characteristic, 

 was apparently not noted by these investigators, who were more 

 interested in the hemolysis. Heated bovine serum alone aggluti- 

 nates guinea-pig corpuscles only feebly; horse serum agglutinates 

 them better, but rather slowly. A mixture of the two sera, how- 

 ever, brings about in a very few moments an extremely marked 

 clumping of large masses of corpuscles, which soon afterward lose 

 their hemoglobin. 



Borclet and Gay's explanation of this is then quite evident; the 

 corpuscles in such a mixture fix first the bovine and horse ambocep- 

 tors and then the alexin.* A certain amount of time is necessary for 

 this to take place, but as soon as the corpuscles become laden with 



* It would be very difficult to define the proportions in which each of these 

 two sensitizers is fixed; it is, moreover, of little importance. The essential fact 

 is to recognize that either of them will suffice to sensitize. 



