In the previous paper, the growth inhibitory action of kanamycin against tubercle bacilli in vitro and in mice was reported. The effect of this new antibiotic was striking and almost comparable with streptomycin. Thus, this agent has become the first promising substance ever brought into our examination since 1948. Although use of mice for the screening test of presumed antituberculous agents is a general trend of recent years, a historical survey of the literatures of streptomycin, paraaminosalicylic acid, 4-acetylaminobenzaldehyde thiosemicarbazone and isonicotinic acid hydrazide shows that the final decision of the efficacy must be done according to the guinea pig experiment.

In this connection, the present authors designed a large scale of guinea pig experiment as will be reported in the subsequent papers. Before entering into the experiment, however, a preliminary trial was undertaken in a smaller scale in order to grasp the outlook of the main experiment. The result was described in this paper as follows.