386 STUDIES IN IMMUNITY. 



however, one fact that at first sight might seem not to agree with 

 our explanation. 



When guinea-pig corpuscles are treated with a sufficient amount 

 of fresh horse serum, washed, and then added to heated bovine 

 serum, an energetic agglutination occurs, due to the absorption of 

 the colloidal substance by sensitized and alexinized corpuscles. 

 It would also seem as if under these conditions an active hemolysis 

 should take place, since we know that hemolysis is also favored by 

 the addition of colloid. The hemolysis under these conditions, 

 however, is very slow and slight, although the agglutination is rapid 

 and strong. 



It is to be noted that in such an experiment the alexin and colloid 

 are fixed successfully and at relatively long intervals apart. It 

 would seem as if the fact that the alexin had been acting for a long 

 time had increased the properties of molecular adhesion on the 

 part of the corpuscles to its maximum, and as if the exaggerated 

 absorption of the colloid had brought about an unusually intense 

 agglutination. In other words, it would seem as if there were some 

 antagonism between hemolysis and agglutination. It would seem 

 as if, when agglutination is too powerful, the corpuscles would, so 

 to speak, coagulate, and so become more resistant to alexin. The 

 proof of this supposition, which incidentally brings out the fact that 

 absence of hemolysis in the case in point in no way disagrees with 

 our interpretation, may be experimentally shown in the following 

 manner: Corpuscles that have been subjected to horse serum and 

 subsequently to a strong agglutination by heated bovine serum will 

 resist hemolysis on the subsequent addition of both horse serum 

 and bovine serum, in other words, when subjected to a mixture 

 that is highly hemolytic for ordinary corpuscles. The agglutinated 

 corpuscles, then, have a greater resistance than the normal corpuscles. 



In short, the hemolysis due to these three substances is a phe- 

 nomenon dependent on the manner in which the various factors 

 are added, and its mechanism is so delicate as to be easily destroyed 

 by varying the experimental conditions. 



The reverse of this condition may be produced also, that is to 

 say, an active hemolysis accompanied by a slight agglutination. To 

 increase this hemolytic tendency a small amount of guinea-pig 

 alexin is added to the mixture of bovine serum plus horse serum. 



