154 THE UNIVERSITY SCIENCE BULLETIN. 



The litmus milk was kept for six weeks before being discarded. 

 The cultural reactions are tabulated in table II. It will be observed 

 from the table that none of the strains exhibited any variation in 

 the media commonly, used in routine laboratory procedure. All 

 strains gave acid in dextrose, mannite, maltose, negative in lactose 

 and saccharose, no liquefaction of gelatine, no indol, and an initial 

 acidity in litmus milk. Three strains gave slight acidity in salacin, 

 one strain gave no acid in xylose, Rawlings' strain, and one gave 

 acid only after ten days. Two strains were negative in dextrin. 

 All strains except No. 7 gave a distinct greenish-black cloud around 

 the stab in 2 per cent peptone gelatine, but no gas. In litmus milk 

 all but six organisms remained a permanent lilac color, six turned 

 back to neutral in three weeks and one became a deep blue after one 

 week. 



In addition to the above strains an organism isolated from the 

 feces of a clinical case of mild tj'phoid was studied. This organism 

 is designated as No. 5. The patient at no time gave a positive 

 Widal. The organisms were abundant in the feces and culturally 

 differed from Bacillus typhosus only in giving very slow blackening 

 of lead acetate agar, negative in xylose, negative in dextrin, positive 

 in rhamnose, and distinct alkaline reaction in litmus milk after 72 

 hours, but with no saponification. 



DISCUSSION. 



Weiss (2) has reported the cultural characteristics of thirty-one 

 strains of typhosus and groups them according to xylose fermenta- 

 tion. Three of his strains produced acid slowly and four remained 

 negative. One of the negative strains was the Rawlings' strain 

 which we also found to be negative. 



Teague (3) objects to such a classification on the basis of xylose 

 fermentation on the ground that the so-called negative strains are 

 not really incapable of fermenting xylose, but ferment it slowly. 

 Four of his strains failed to give acid on the thirty-second day, but 

 these strains could be trained to give acid by plating on xylose agar. 

 No attempt was made by the author to discover mutants from nega- 

 tive strains on any of the carbohydrates used. 



Our strains were uniformly negative on dulcite and arabinose.. 

 Teague (3) reports eleven out of forty-one strains fermenting these 

 sugars slowly. Krumwiede (4) also reports the fermentation in 

 dextrin as varying with the sample used. The two cultures giving 

 negative in dextrin might, therefore, have shown typical acid pro- 

 duction with another sample. 



