Investigation of vicissitude of circulating lymph volume and its bilirubin contents as well as those of serum bilirubin were carried out together with the clarification of the presence of verdohemoglobin, a matrix of biliverdin, by administration of physiological saline or hemoglobin solution via femoral or mesentherial vein on thoracic duct-fistled dogs of the sound, the liver-damaged with the administration of carbon tetrachloride, or the reticuloendothelium-blocked to clarify the characteristic of thoracic duct lymph during the process of bile pigment formation in vivo, and the following results were obtained: 1. It was found that thoracic duct lymph volume always reduced by administration of physiological saline or hemoglobin solution after a temporal variation in the early stage of administration. 2. Temporal increase of bilirubin contents in thoracic duct lymph would often appear even under the administration of physiological saline, and it was apparent in the administration of hemoglobin solution. 3. The increase of bilirubin contents in thoracic duct lymph appeared by turns; the sound > the reticulo-endothelium-blocked > the liver-damaged. It appeared, on the other hand, most dominant by the mesentherial administration on the sound and by the femoral one on the other two. 4. Vicissitude of bilirubin conents in the thoracic duct lymph after the administration of hemoglobin solution was remarkable in the sound, pretty in the reticulo-endothelium-blocked, and scarce in the liver-damaged. 5. Though vicissitude of serum bilirubin seemed to be similarly controlled to the one of thoracic duct lymph, there was not always correlation between the two, and there appeared that at least a part of bilirubin formed in the liver might be transported into the blood flow. 6. No biliverdin could be extracted from the thoracic duct lymph, and the transport of verdohemoglobin from liver to the blood flow, especially this could not be found via thoracic duct lymph.