THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN 



Vol. XIII. ] JULY, 1920. [Xo. 15. 



A Comparison of the Antigenic and Cultural Character- 

 istics of a Number of Strains of Bacillus Typhosus * 



BY CORA M. DOWNS. 

 Department of Bacteriology. 



ALTHOUGH it has seemed to be the general concensus of opinion 

 that Bacillus typhosus is a verj' homogeneous organism, j^et in 

 view of the fact that some obsen-ers have reported cultural and 

 serological variations, it was thought advisable to investigate the 

 cultural and serological reactions of the strains of typhosus used in 

 this laboratory. 



The work done may be divided into three phases, namely: cul- 

 tural reactions, agglutination and absorption tests, and the "Widal 

 reaction. The source, place of isolation, name and date of the or- 

 ganisms u.sed are tabulated in table I. 



CULXriL^L REACTIONS. 



Technique : The carbohydrate medium used was semisolid, to 

 which was added 1 per cent of the carbohydrate desired, and 

 Andrade indicator to make a pale, flesh color when cold. As a check 

 a second set of determinations was run, using meat infusion broth 

 adjusted to Ph, 7.0, to which 1 per cent of the carbohydrate was 

 added, litmus being used as an indicator. For the lead acetate agar 

 1 per cent lead acetate solution was added to semisolid medium. 

 Two per cent peptone gelatine, made according to a formula devised 

 by Treece (1), was used for liquefaction and to test for gas produc- 

 tion in noncarbohvdrate media. 



* Received for publication October 18, 1921. Abstract published in Abstracts of Bac- 

 teriologj-, Feb. 1920, vol. IV', No. 1, p. 19. 



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