IMMUNE SERA 



the serum will lose its agglutinating power not only 

 for that organism but also for all other varieties that 

 it formerly acted on. Saturated with the others, its 

 action upon the first is reduced little or not at all. 



The serum of an animal immunized against two 

 microorganisms A and B, loses its agglutination 

 when saturated with A, only for A. Saturated 

 with A and B, it loses agglutinating power for both. 



Park, 1 who has devoted considerable attention to 

 this subject finds that the absorption method 

 simply proves that when one variety of bacteria 

 removes all agglutinins for a second, the agglu- 

 tinins under question were not produced by that 

 second variety. 



Specific and group agglutinins may perhaps be 

 better understood by means of the following dia- 

 gram. We assume that the typhoid bacillus pos- 



B C 



E F 





. Typhoid Bacillus 



E H 



Colon Bacillus 



Dysentery Bacillus 

 FIG. 5. 



sesses considerable protoplasm A, which is specific 

 for the typhoid bacillus, that it possesses also certain 

 protoplasm B, which is common to it, and to the 



1 Park and Collins, Journ. Medical Research, Vol. vii, 1904. 



