Of 44 lungs resected after chemotherapeutic treatment the authors studied the shapes and stainability of bacilli centering around the distribution of tubercle bacilli in focal tissues of 20 cavities proven to be acid fact bacilli positive to the Z.-N. test, 17 inspissated cavities, and 17 encapsulated caseous foci to the total of 54 foci; and obtained the following results. 1. The acid resistance of the tubercle bacilli within the focus is not affected up to 60 days after the formalin fixation. 2. The bacillus detection rate of the H test does not differ from that of the Z.-N. test. 3. In the cavity the distribution of tubercle bacilli is greatest on the surface layer of necrosis, showing mostly the acid fast type by A.-F.-G. test, while in deeper layer the distribution is markedly less and the acid fast type decreases as well. The readily stainable type by Z.-H. test are found least in the surface layer and they increase in number in deeper layer. This type of bacilli can be found also in the typical granulative layer, atypical granulative layer and atelectatic layer, though only a few in number, but epitheloid cells, the cells phagocytosed by Langhans' giant cells, are extremely rare. Moreover, the cavity expelling tubercle bacilli before operation the bacillus distribution on the surface layer of necrosis is decreased as compared with that in the cavity of the group expelling no bacilli. In the inspissated cavity bacilli are found greatest in the central portion of the caseous focus, revealing mostly the acid fast type by A.-F.-G. test, and nearer to the basal part the bacillus distribution as well as the acid fast type decrease gradually, however, the degree of such a decrease is less marked than in the case of the cavity. No tubercle bacilli can be found the atypical granulative layer. In the encapsulated caseous ocus degraded cells are more numerous than those undegraded cells. Undegraded cells are distributed evenly in the entire caseous focus, while degraded cells are found mostly in the portion where the damage is greatest. The distribution of the acid fast type by A.-F.-G. test does not generally show any fixed tendency, but there is an increasing tendency of the acid fast type on the face of the destroyed part. Deformed bacilli are evenly distirbuted in all foci and in entire layers, but the deformation tendency is somewhat diminished on the damaged face of the encapsulated caseous focus. 4. As for the relationship between the bacillus distribution and the growth rate of culture the number of tubercle bacilli is greatest in the culture negative gruop of cavity, and the bacillus distribution is decreased on the necrotic surface layer. In all other foci there can be recognized no relationship between the bacillus distribution, the distribution of the acid fast type and readily stainable type and the growth rate. 5. With respect to the chemotherpeutic method, in the cavity that showed bacilli the greater the amount of antituberculous agent used the greater is the number of bacilli, and the bacillus distribution and the distribution of the acid fast type are abundant on the necrotic surface layer. Likewise in the group treated concurrently with INH the bacillus distribution and the distribution of the acid fast type on the necrotic surface are greater than in the group that had no concurrent use of INH. In the inspissated cavity the greater the amount of the drug used, the lesser is the bacillus distribution in the central portion of the caseousfocus, while in the group treated concurrently with INH the bacillus distribution is greater in the central portion of the caseous focus. In all the encapsulated caseous foci no relationship between the chemotherapy and the bacillus distribution can be recognized.