AGGLUTINATION AND DISSOLUTION. 179 



power to destroy red blood corpuscles disappears on heating to 

 55 degrees.* 



The most destructive and powerful action that we have noted in 

 studying sera is the effect of hen serum on rabbit corpuscles. One 

 part of defibrinated rabbit blood is rapidly dissolved by two or 

 three parts of hen serum. The destructive effect of this serum for 

 rat corpuscles is also very distinct; it is very slight for guinea-pig 

 corpuscles. 



Dog serum dissolves hen corpuscles energetically, although it 

 leaves their nuclei intact; it also attacks rabbit and guinea-pig red 

 blood corpuscles. 



Guinea-pig serum and rabbit serum have both a very slight 

 destructive effect on hen and human corpuscles. Guinea-pig serum 

 has only a very slight and delayed effect on rabbit corpuscles. Rab- 

 bit serum, however, is much more active against guinea-pig cor- 

 puscles, but is almost entirely without effect on rat corpuscles. 



It should be noted in these tests that the agglutinating and the 

 dissolving property differ in different specimens of the same variety 

 of normal serum; that is, there are individual differences which may 

 be rather marked. 



No general rules can be drawn from these facts. There is no 

 means, for example, of classing corpuscles in groups according to 

 their sensitivity to agglutinating or dissolving action. 



The corpuscles of a given species may be very easily agglutinated 

 by one normal serum and resist another. In the same way it can- 

 not be shown that a serum that shows itself very active for one 

 species of corpuscles will be equally active for other varieties of 

 corpuscles. For example, hen serum affects rabbit, dog and rat cor- 

 puscles, but has almost no effect on guinea-pig corpuscles. Nor 

 can we assert, as a general rule, that a serum that is capable of dis- 

 solving a given species of corpuscles will necessarily agglutinate them 

 energetically. For example, although hen serum dissolves rabbit 

 corpuscles easily and also agglutinates them strongly, we find, on 

 the other hand, that dog serum agglutinates hen corpuscles only 

 faintly, although it destroys them actively. It is evident, then, that 



* There is, however, an apparent exception. Dog red blood corpuscles are still 

 dissolved by sera heated to 55 degrees. These corpuscles, however, are also dis- 

 solved by their proper serum. It is, therefore, not a question of alexic activity, 

 but of a particular fragility on the part of dog corpuscles. 



