70 TECHNICAL BULLETIN 5. 



Maimose. — This sugar was fermented by all the strains. The minimuni acidity 

 by any strain was 0.6 and the maximum 1.3 per cent. The average for the 112 

 strains was 0.9 per cent acid. 



Xylose. — This sugar was fermented by all the strains, but none produced marked 

 quantities of acid. The minimum produced by any strain was 0.1 and the maximum 

 0.4 per cent, with a mean of 0.25 per cent for the 112 strains. Therefore it may be 

 said that these puUorum strains are not strongly xylose positive. 



Adonile. — For the most part the initial acidity was not greatly changed. The 

 minimum figure ob.served was an alkalinity of 0.1 per cent and the maximum an 

 acidity of 0.1 per cent. As a group the.se strains were adonite-negative, the curve 

 of results from the 112 strains running close to the line of initial acidity. 



Erythrol. — This carbohydrate was not fermented significantly by any of the. 

 cultures of Bad. pulloru-in studied. All strains gave a reduction of the initial acidity. 

 The acidity ranged from a minimum of — 0.4 per cent to a figure which represented 

 no change from original acidity. Therefore these 112 strains are erythrol negative. 



Saccharose. — There was no appreciable amount of acid produced in this carbo- 

 hydrate. The minimum reading was — 0.2 per cent and a few readings showed no 

 change from the initial acidity. The average acidity determination for the 112 

 strains was - — 0.2 per cent. There were two exceptions, strains 67 and 84, which 

 showed a determination of — 0.4 and — 0.5 per cent for acidity. Therefore in 

 saccharose there is no acid formed by Bact. pullornm. 



Dulcite. — All the 112 strains of Bact. puUorurn showed a marked reduction of 

 acidity. A few strains did not change the initial acidity, the range being between 

 no change of acidity and — 0.4 per cent. There were three exceptions, however, 

 cultures 32, 46 and 47, which produced the following results: — 0.6, — 0.5 and 

 — 0.5 per cent, respectively. Therefore it may be said that the results from these 

 determinations indicate that Bact. jyuUorum is dulcite negative. 



Dextrine. — The initial acidity was readily reduced by all strains studied. The 

 readings ranged from no change in acidity to — 0.3 per cent. There were no ex- 

 ceptions, all cultures demonstrating this reduction. 



Lactose. — The initial acidity was reduced by all strains. The readings ranged 

 from no change in acidity to — 0.4 per cent, the mean reading being — 0.12 per 

 cent. Bact. puUorum may be considered, consequently, lactose-negative as regards 

 acid production. Two strains, 93 and 109, were unusually prompt in this particular. 

 Both strains gave a reading of — 0.4. 



Raffinose. — The acidity was reduced by all the puUorum strains. The average 

 reading for the 112 cultures was — 0.2 per cent. Strain 48 was capable of greater 

 alkaline production than the others, giving a result of — 0.5 per cent. 



Inulin. — All strains of Bact. puUorum were negative in this carbohydrate, the 

 mean reading being — 0.19 per cent. There was a prompt reduction in initial 

 acidity, only one culture of the 112 showing no change in the initial acidity. 



Maltose. — None of the 112 strains produced any acid. The change was usually 

 marked in all tubes on the fifth daj'. There was an average reduction of acidity of 

 — 0.18 per cent. 



Glycerine. — None of the 112 strains produced any acid in glycerine. The 

 determination on the fifth day showed a reduction in the final acidity, averaging 

 — 0.1 per cent. 



Conclusions from the Fermentation Tests. 



From the tests reported concerning the fermentation of the 1 12 strains 

 of Bact. puUorum, it appears that tliis organism is positive in dextrose, 

 galactose, mannose, mannite, levulose, xylose and arabinose; and negative 

 in glycerine, maltose, adonite, dulcite, lactose, dextrine, saccharose, iuulin, 

 erythrol and raffinose. In saUcin there is a shght indication of fermenta- 

 tion, at least a shght acidity in a large percentage of the strains. All strains 

 of this organism studied showed a marked tendency to produce gas in 



