By injecting bovine blood into the subcutaneous tissue on the inner side of the rabbit femur the author studied histochmeically the Decomposition of hemoglobin-heme as well as pursued serologically changes of hemoglobin-globin; and obtained the following results. 1. When bovine blood is injected subcutaneously, the hemoglobin decomposition takes place relatively quickly outside the histiocytes. Namely, on the second day after the injection the formation of hemosiderin, on the third day of bilirubin, and on the fifth day of hematoidin cristals, on the ninthday of bilifuscin can be recognized outside the cells; and the number of these is increased on the 14th day. On the other hand, within histiocytes are formed hemosiderin granules on the fifth day, hematoidin crystals on the seventh day, and hematoidin crystals are increased in number on the 14th day. 2. The precipitation of globin in the tissue is somewhat slow on the first day of the injection, but from the second day to the 15th day the precipitation presents the value of 32, 000-fold, and this maximum has been maintained throughout the period observation. 3. Therfore, the degeneration of globin observable at the process of the hemoglobin destruction is extremely trivial yet persistent, and this fact corroborates the theory advocated by K. Kajiro et al. 4. From the fact that hemosiderin is formed from hemoglobin, and then the hematoidin (bilirubin) or billifuscin is fomed and that the antigenic value of globin in the tissue is unchanged even at the stage when hematoma has almost completely disappeared, it is believed that globin is decomposed in the course of bilirubin formation from hemoglobin and is kept in the tissue for a long period of time. Therfore, the theory that indirect bilirubin is bilirubin-globin seems to be not appropriate.