1951 年 4 巻 6 号 p. 347-359
Since the discovery of “Bact. coll. mutabile” by Massini, there have been numerous reports on the secondary colony formation of bacteria caused by carbohydrate. On the other hand, in Japan R. Kobayashi and his coworkers found that there is a peculiar type of variation which occurs in the same manner among the bacilli of colon-typhoid-dysentery group when grown in plain broth and causes these variants to form secondary colonies on the media containing either galactose, lactose or raffinose (i.e. carbohydrates composed of galactose molecule) . They named this variation as “variation of mutabile type” considering it as an independent variation, and have investigated it systematically. This variation was called at first as “variation of mutabile type” because of its seeming resemblance to the variation of Massini's “Bact. coll. mutabile”, although recent investigations have indicated the essential differences between these two types of variation. Considering these aspects, Ushiba advocated that, to avoid confusion, this variation might be called as “variation of mutabile type (MURASE) ” referring to the name of its discoverer or “galactose variation” to distinguish it from the variation of Massini's “Bact. coll. mutabile”.
The present report is dealing with the occurrence of this variation originated from rough phase of bacteria and its systematic studies. (It seemed likely that Ohno and Ito et al. have obtained the mutabile variant from bacteria of R phase, but there are no detailed and precise descriptions on it.)