16 



Table #19. B. Coli Antigen with Antifat Serum 



Table #20. B. Coli Antigen with Antiprotein Serum 



Table #21. B. Coli Antigen with Normal Serum 



A control suspension of the B. coli antigen did not show 

 agglutination* 



Comparison of the results by use of the complement 

 fixation and agglutination tests give a very striking 

 picture. We find that the fat antigen (table 19) gives 

 rise to specific antibodies and that the protein antigen 

 (table 20) is of negligible importance in this respect. 



C. The Precipitin Reaction. This test has to do 

 with the precipitation of solid matter out of solution of 

 invisible "colloidal suspension". Obviously the B. coli 

 and protein antigens cannot be used, but the fat antigen 

 is suitable for the reaction. The most desirable antigen 

 is one which is perfectly clear and transparent. Clarity, 

 in a fat suspension, depends upon the state of the fat 

 particles, so that the greater the degree of dispersion, 

 the greater the clarity. A perfectly clear antigen was 

 not obtained, but a sufficient degree of dispersion was 

 made to run the tests. Ten drops of serum was layered 

 under ten drops of antigen, and after the incubation at 

 37C for fifteen minutes, the following results were 

 obtained. 



