The author performed basic-dye vital staining of ascites cells, especially phagocytes, of mice, rats, rabbits, cats, dogs and chickens or acidic-dye vital staining by injecting dyes into the peritoneal cavity of these animals, by means of tissue culture in both cases, and obtained the following results: 1. In the cases of basic-dye vital staining phagocytes present a neutral red rosette formation as their basic picture; and mitochondria are distributed around the nucleus, revealing an appearance much like a moncyte; and the higher the animal is the more pronounced is this tendency. 2. In the acidic-dye vital staining as applied to mice, at each additional injection of the dye the degree and percentage of staining cells increase step by step as if it indicated an increase in the degeneration of cells with each injection. Although these cells do not demonstrate characteristics in so high a degree as in the case of basic dyes, they, nevertheless, present essentially a staining picture resembling the findings on monocytes, considering these cells prior to degeneratiou. From these findings it may be said that the picture of vital staining in the ascites cells resembles that of monocytes.