28 



L. A. JULIANELLE 



PI, and LI agglutinate strains A2, A3, A5, H2, PI, P3, P4, P5, Tl, 

 T2, T3, T6, T9, X, Jl, and LI. Serum T9 agglutinates P3, T2, T9 

 and X. Serums A5, PI and LI are unquestionably the same since 

 they give the same reactions. It will be noted that strains T2, T9 and 

 X are agglutinated by all the serums, and P3 by all the serums except 

 Al. Aside from these atypical agglutinations, the strains fall definitely 

 with one serum. Apparently, then, the agglutination tests give the 

 following grouping : 



L Al, Fl, P2, S2, T5, T8, C15, C16, CIS. 



II. A2, A3, AS, H2, PI, P4, P5, Tl, T3, T6, Jl, LI. 



III. T2, T9 X and possibly P3. 



TABLE 13 

 RESULT OF ABSORPTION TESTS ANTIGENS * 



Serum Absorbed With 



* indicates that strain did not agglutinate prior to absorption; figures represent dilu- 

 tion oi final positive agglutination; + indicates no test. All controls were negative. 



ABSORPTION TESTS 



In order to further identify the groups suggested by the aggluti- 

 nation reactions absorption tests were conducted, employing the technic 

 of Small and Dickson. 59 One c c of a 1 : 10 dilution of the immune 

 serum was mixed with 4 c c of the concentrated antigen in a sterile 

 centrifuge tube. This amount of the antigens was found sufficient to 



69 Jour. Infect. Dis., 1920, 26, p. 230. 



