1. The absorption maximum of oxyhemoglobin gradually shifted to the short wave length on the subcutaneous administration of blood to white rat and it displayed at 576, 572, 550, 490, 538, and 495 mμ and bilirubin displaying the absorption maxima at 478-480 mμ. And the product with the absorption maxima at 490 and 495 mμ was thought to be the iron acetate of bilirubin since the photometric and histochemical observations. 2. The absorption maximum of oxyhemoglobin shifted to the short wave length on the subcutaneous administration of blood to chicken, besides, a remarkable green pigment (biliverdin) was produced at the relatively early period and choleglobin with the absorpticn maximum at 630 mμ was identified with the absorption maximum of oxyhemoglobin at the same time. The region of biliverdin gradually shifted to bilirubin from the circumference. 3. The golden yellow hematoidin crystal appearing in bilirubin of yellow pigment displayed the absorption maximum at 478-480 mμ and it agreed with the absorption maximum on the subcutaneous injection of crystal billirubin in advance. Moreover. the absorption curve in the region with the collection of hematoidin crystal showed the most typical absorption curve of bilirubin. 4. The above results of absorption curve agreed with the results of histochemical studies by Nanba and Nishinobu in our department, and it was proved that the decomposition process of hemoglobin in vivo agreed with that of experiment in the test-tube.