XI, B, 4 Wade: Carbohydrate Fermentation 161 



difference between these and his new strains. Rowland (13) de- 

 scribed the organism which he employed in vaccine work as 

 forming acid in dextrose and mannite, but not touching lactose, 

 saccharose, dulcite, adonite, inulin, and litmus milk. 



At the International Plague Conference held in Mukden, (1911) , 

 the idea that the strain of organism in pneumonic plague differed 

 from that ordinarily found in bubonic plague was discussed. 

 Zabolotny(l4) inclined to this view, but no definitely confirmatory 

 evidence was adduced. No results of cultivation in sugar media 

 were reported at the conference. In summing up the existing 

 evidence. Strong, (15) and later Strong and Teague, (16) declared 

 that there was no distinction between the bubonic and the pneu- 

 monic organisms demonstrable either culturally or by study of 

 virulence and inmunology. 



Schobl,- working in the Bureau of Science laboratories in 1914, 

 made parallel reactions on litmus carbohydrate agars, using 

 seventeen reagents and twenty-one strains of B. pestis, including 

 known Chinese strains and the laboratory avirulent strain. He 

 demonstrated no qualitative fermentation differences, but ob- 

 tained results somewhat at variance with those of others in that 

 saccharose and glycerin gave acidification, as well as dextrose, 

 levulose, galactose, maltose, mannite, and salicin. Lactose, raf- 

 finose, dulcite, dextrin, amygdalin, inulin, inosite, adonite, sor- 

 bite, and nutrose gave no acid. 



The latest report of such an investigation is that of Berlin, (17) 

 who studied fifty-five strains, employing fourteen sugars in a 

 concentration of 1.3 per cent in agar. He obtained uniform 

 results, all cultures giving acid in arabinose, glucose, galactose, 

 maltose, mannite, and levulose and no change in saccharose, lac- 

 tose, raffinose, starch, dextrin, inulin, dulcite, and adonite. He 

 concluded that the age of the cultures and their virulence played 

 no role in the acid formation. 



The minor differences which seem apparent upon comparing 

 various reports would appear to be due either to technical varia- 

 tions by different investigators, or to the existence of subspecies 

 recognizable only by special methods of investigation. Analysis 

 of the reports makes the latter hypothesis seem the less probable, 

 since no one has reported variation among the cultures under 

 his hand, no matter how widely his results differed from those 

 of others. There seems to be no evidence of modification of 

 fermentative power after prolonged artificial cultivation. 



' Personal communication. 



