In the present report the author presents the results of observations on the caron-paricle phagocytosis and neutral red vital staining of normal human platelets and chicken spindle cells. 1) Normal human platelets possess both the phagocytic and adsorption capacities, differing according to the type of movement. Those with type Ⅰ and Ⅱ movement show a marked phagocytosis while those with type Ⅲ and Ⅳ, a marked adsorption capacity. The rate of the phagocytosis is at its maximum after one to two hour culture, and thereafter it gradually falls with the lapse of time, whereas the rate of the adsorption capacity becomes higher and higher along with the lapse of time. 2) In neutral red vital staining these appear extremely minute granules stained either reddish brown or dark red, but they differ somewhat according to the type of movement. Those with type Ⅰ and Ⅱ movement have a lower rate of staining while those with type Ⅲ and Ⅳ a higher. 3) Next, chicken spindle cells possess both the phagocytic and adsorption capacities but they also differ somewhat with the type of movement. Those with type A and D movement have a marked phagocytic power whereas those with B and C type movement a marked adsorption capacity, but the latter have hardly no phagocytic capacity. The average rate of the phagocytosis in bone marrow reaches its maximum after 6-hour culture and that in peripheral blood after 3-hour culture. 4) After neutral red staining minute granules appear stained either dark red or brown in spindle cells, but like platelets the staining differs according to the different types of movement. Those with type A and C movement show especially minute granules stained slightly, while those with type B and D movemeut reveal granules somewhat larger and stained deeper. The average stainability in the case of bone marrow after 5-hour culture reaches its maximum and that in peripheral blood after 4-hour culture, respectively.