- 6 

 Table I. 



regain their power of acid production or develop this power. A series 

 of 20 transfers with a lapse of two days between each failed to cause 

 them to ferment sugar to any appreciable degree. It should be stated, 

 however, that all the organisms labeled Zopfii, Zenkeri, and mira- 

 bilis, with the exception of Nos. 3 and 17, grew very sparingly on all 

 the laboratory media, although all gave the characteristic colonies on 

 gelatin plates. 



All the organisms which fermented dextrose readily, fermented sac- 

 charose, mannose, and galactose, but failed to ferment lactose, even when 

 grown in lactose broth for several days. In the fermentation tubes con- 

 taining lactose broth inoculated with these organism, there appeared good 

 growth in the open arm, but none whatever in the closed arm. This 

 suggested the idea that it is much easier for these organisms to get their 

 oxygen from the air than from lactose and, therefore, this sugar is not 

 attacked. If this conclusion were correct, it was thought possible to 

 cause the non-lactose fermenting organisms to ferment this sugar if they 

 were deprived of all other sources of oxygen. 



Flasks each containing 100 c. c. of sugar free broth, to which 2% 

 of lactose had been added, were inoculated with strains of Proteus 

 vulgaris which had failed repeatedly to ferment lactose under aerobic 



