1. In the bile of rabbits, the metabolisms of biliverdin and bilirubin are in a solucible state, and which have a ratio of 2: 1 in normal animals. 2. In the production of biliverdin, the liver, especially the parenchyma of the liver has a very important role, while that of the reticulo-endothelial system is rather minor. However, in the case of glucose administration, the reduction of bilirubin from biliverdin is performed in the reticulo-endothelial system, thus conferring an important part of this system. 3. The production of bilirubin is performed primarily extrahepatically, and the participation of the extrahepatical reticuloendothelial system is of a conservative nature, thus denying us any
willingness to agree to the theory of bilirubin production in the reticulo-endothelial system. 4. On administration of hemolysed blood, bile pigments in bile demonstrate a remarkable increase, while as compared when injected into the auricle veins in cases of administration through the
portal vein a decline in the functions of the liver reticulo-endothelial system is seen, causing a decrease in biliverdin amount. In the former modus of administration, an occasional stimulation of the liver reticulo- endothelial system is seen, causing reduction of biliverdin
to bilirubin. 5. Concluding from these facts, biliverdin in rabbit bile occupies the role of an intermediate product in the production and metabolism of bilirubin.</p