62 MARGARET C. PERRY AND W. F. MONFORT 



days than with the substituted 0.75 per cent Difco incubated 

 for 2 days, while with those grouped under reference numbers 

 10 and 11 agreement between the original reactions in Difco 

 and in the standard broth was complete. The number of anom- 

 alies discovered would probably have been even greater had 

 we been able to use the standard medium throughout this work; 

 but our purpose of segregating atypical forms was served in a 

 measure by the provisional grouping based upon the reaction in 

 Difco peptone broth. 



The methyl red reaction was tested after 2 days' and after 

 five days' incubation in standard Witte broth: but 1 strain (9c) 

 was acid after two days and alkaline after five days; all the rest 

 gave concordant results for the two incubation periods at that 

 time. 



Of the 25 uric acid positive strains, two (9a and 9b) are methyl 

 red negative and have the general characters of Bact. aerogenes. 



Ten strains give anomalous results with the methyl red and the 

 Voges-Proskauer reactions: Nos. 4 and 5a fail to ferment salicin, 

 dulcitol, adonitol, starch and glycerol. The last of the 9c strains 

 and the first seven of the 10b strains are positive to both methyl 

 red and the Voges-Proskauer reaction; and the last listed, 10b, is 

 negative in both these reactions; two of these strains were lost 

 before salicin tests were made; but the characters of these eight 

 strains are predominantly those of the aerogenes type. 



Thirteen strains are uric acid positive, methyl red positive 

 with the Voges-Proskauer reaction negative or not recorded: 

 5b fails to ferment salicin, dulcitol and adonitol and can not be 

 assigned a place; the two strains 6a resemble Bact. coli in most 

 respects; 6b is sucrose, salicin, dulcitol positive, and is probably 

 Bact. aerogenes; the first two 9c strains resemble Bact. com- 

 munior; 10a is perhaps more like Bact. aerogenes than Bact. 

 communior; 10c liquefies gelatine and ferments all carbohydrates, 

 etc., save starch and dulcitol: the first four strains numbered 

 lOd fennent actively all the carbohydrates, etc., except starch 

 and glycerol; the last lOd fails to ferment salicin, starch and 

 glycerol. Whether these 13 strains, departing more or less from 

 type forms, are to be regarded as colon forms from soil or as 



