抄録
Several strains of mutabile type variant were obtained by cultivating several strains of E. coli including E. coli 0-15 for a long time in broth. The present paper reports . the results of the observation on the galactose fermentation ability of the strains of the daughter type mutabile variant (M TMurase) and those similar to them (RT) which were obtained from their cultures on the media containing galactose factor (galactose, lactose and raflinose) .
The author discovered many strains of organisms, which ferment galactose with acid and gas, when the above mutabile type variants ware cultivated on the culture media containing galactose. However, such orgauisms were not present in the inoculum, but they were found in the colonies grown on the agar plate. Consequently, the author recognized that these organisms are galactose fermenting daughter type variants (tentative name) (RT), though merely considered from the outside view in the growth.
This finding also supports the claim by Ushiba and Kitasato, who reported the galactose non-fermenting character of the MT variant. As to the readiness and difficulty of the occurrence of this kind of strains, rate of the occurrence and the condition under which this kind of strains appear, separate report is scheduled to follow at a later date.
