AGGLUTININS AND PRECIPITINS 



emulsion of typhosus and 0.5 c.c. thin emulsion colon. After incubation only 

 tube i shows agglutination, because the colon agglutinins have been ab- 

 sorbed. The protocol of this experiment with the controls follows: 



SERIES A (ABSORBED BY TYPHOSUS) 



1. Fluid A 0.5 c.c. 4- 0.5 c.c. typhosus = no agglutination. 



2. Fluid A 0.5 c.c. T 0.5 c.c. colon = agglutination. 



SERIES B (ABSORBED BY COLON) 



3. Fluid B 0.5 c.c. + 0.5 c.c. typhosus = agglutination. 



4. Fluid B 0.5 c.c. + 0.5 c.c. colon = no agglutination. 



CONTROLS 



5. Saline 0.5 c.c. + 0.5 c.c. typhosus no agglutination. 



6. Saline 0.5 c.c. -f- 0.5 c.c. color = no agglutination. 



This experiment shows only the essentials of the specific absorption. It 

 may be further elaborated by making a series of dilutions of the treated 

 serum so as to show the fact that the titer is essentially unimpaired. 



Result 



Result 



This experiment shows that the process of absorption removes 

 only the specific agglutinin and leaves the other agglutinin un- 

 changed. As a matter of practical fact, the typhoid agglutinin re- 

 mains unchanged, but the colon agglutinin may be somewhat reduced 

 in titer, perhaps to 1-800 or even as low as 1-300. In a combined 

 serum of this sort with the typhoid agglutinin of high titer, part of 

 the agglutinin for colon is the result of a typhoid minor agglutinin 

 which is removed by absorption with typhosus, thus reducing the 



