48 o. iSHii 



Bad. dysenteriae Shiga serum (1:50), shows sUght agglutina- 

 tion with the Flexner and Strong strains; but the reaction is 

 stronger with formalin than without; with the Hiss strain, there 

 is no agglutination either with or without formalin. This serum 

 does not have a tendency to group agglutination as do sera of 

 other Bad. dysenteriae groups, and horse serum serves for agglu- 

 tination as well as specific serum. 



HORSE SERUM AGGLUTINATION FOR BACT. DYSENTERIAE GROUP 

 AND BACT. COLI. (tABLE 5) 



Lentz, Park and Williams have found that Bad. dysenteriae 

 is agglutinated by normal horse serum, and Gasiakoski, Park 

 and Williams found that Bact. coli is agglutinated by normal 

 horse serum. In my experiments nearly every strain of Bad. 

 dysenteriae and Bad. coli was readily agglutinated by normal 

 horse serum. All samples of horse serum employed, as sho-wm in 

 the table, produced agglutination of both groups of bacilli ; only 

 one strain of Bact. dysenteriae Shiga no. T obtained from Dr. 

 Shiga, showed negative or weakly positive agglutination. 



I have also found that the sera of horses immunized with 

 different bacteria as for instance Corynebad. diphtheriae, the 

 meningococcus, Bact. paratyphosum and the pneimiococcus, 

 have the same agglutinating power as normal horse serum. 



COMPARATIVE AGGLUTINATION TESTS WITH 0.7 PER CENT ACID, 



NEUTRAL, AND 0.3 PER CENT ALKALINE BROTH 



CULTURE MEDIA (TABLE 6) 



Bad. typhosum. Freshly prepared acid broth was used; a 

 heavy growth and actively motile organisms with a tendency to 

 spontaneous agglutination were obtained within 20 hours; with 

 formalin, spontaneous agglutination was prevented almost en- 

 tirely, while without formalin considerable spontaneous aggluti- 

 nation occurred. These cultures were more easily agglutinated 

 with specific serum than cultures grown in neutral or alkaline 

 broth. According to Dreyer, Eisenberg and Volk, Joos, and 

 Weiss acid increases the agglutinating power. 



