Abstract
Strains of mutabile type variants (Murase) were obtained from each of the original strain and its lactose fermenting variant of B. coli mutabile Massini. Though the pattern of the appearance of the variants were different according to the respective strains, but between the original and its variant strains, the patterns were coinciding.
Now this M type, MT (Murase) type and galactose formenting daughter type RT (Fukutome, and others) were obtained and were comparatively examined for their behaviors toward lactose and galactose. The results were as follows.
MT produced lactose fermenting variant in it, thus, it fermented lactose later as it is transformed into a para-coli strain. The RT produced from M type fermented galactose, and became a typical Massini type B. coli, which produces characteristic daughter type variants only on Endo's agar plate. On the other hand, the lactose fermenting variant 'from the original strain (VMT) was found fermenting lactose within as 24 hours, and later in most cases, made the medium alkaline. In addition, the RT produced from M type strain was found to be strongly lactose fermenting as the initial variant (V) was, and further it was galactose fermenting offering a difficulty to distinguish one from the ocher. The lactose fermenting strain (OMT-V) produced from the MT of the original strain showed the same behavior in the lactose fermentation as that of the MT of the variant strain (VMT) making one indistinguishable from the other. However, either of them were galactose non-fermentors suggesting that they were so-called MT. The above findings indicated that the behavior of M type toward lactose showed a strong tendency to coincide with that of the type from which the M type had been produced, though varying in degrees. Furthermore, when viewed from the behavior toward lactose, and others, the RT appeared as if it had returned to the type from which the M type was directly produced.
