I examined the quantity of catalase in organ's tissues of wild duck, goose and pigeon, whose blood in reacting to hydrogen peroxide showed a close resemblance to the blood acatalasemia cases. When we poured hydrogen peroxide on to the blood of these fowl, the blood discolored immediately into a blackish color, and at that time no generation of bubbles could be seen. I used Warburg's manometric method and following results were obtained: I found that Qcat. of blood and bone marrow of these fowl showed an extremely low number, while the Qcat. of liver, kidney and small intestine of these fowl were almost equal index number to those of other animals.