In the bone-marrow tissue culture of the sternal bone marrow obtained from normal persons and patients with various diseases the author observed the granular movements of neutrophils and eosinophils with the aid of the phase-contrast microscope, and obtained the following results: 1. The granular movements of neutrophils and eosinophils in normal persons do not differ much from those in normal rabbits, but in the granules of neutrophils can be observed a movement more minute than in pseudoeosinophils, and the molecular movement can be recognized relatively frequently in the granules of eosinophils. 2. In neutrophils and eosinophils of the cases with hyperfunction of the thyroid gland, the granular movements are vigorous, and a marked acceleration in the motility of cells can be recognized. 3. In neutrophils and eosinophils of hypoplastic anemia. myxedema, cachexia from the stomach cancer, and chronic myelogenous leukemia the granular movement has been found to have slackened in all with a resultant decrease in the cell motility, and this decrease in the functions is most marked in hypoplastic anemia. 4. In the case of eosinophils in anchylostomiasis and bronchial asthma the acceleration of the cell motility can be recognized from the modes of the granular movements. Especially in the eosniphilic granules in anchylostomiasis an abnormal acceleration in the motility can be observed, showing a marked semi-radial linear forward movement of granules. 5. As has been noted in the previous report, the reverse-flow of granaules in the tail end at the early stage of the movement cycle can be seen frequently in the hyperfunction of the thyroid gland (neutrophils and eosinophils), bronchial asthma (eosinophils), and anchylostomiasis (eosinophils), in which already known that the cell motility is accelerated. In contrast to these. the reverse flow movement of granules in the tail end at the terminal stage of the cycle can be observed frequently in hypoplastic anemia and chronic myeolgenous leukemia (all neutrophils and eosinophils), apparetnly showing the decreased functions. 6. From the relationship between the appearance of the reverse-flow movement of grauules in the tail end and the cycle of the cell movement it is possible to estimate the conditions of the cell motility, and clinically ths application of this estimation will offer some criteria for the differential diagnosis and the prognosis of diseases.