The liver is known to the the seat of much of the intermediary nitrogen metabolism in the body. During the last two decades, much has been written concerning the urinary nitrogen partition in hepatic disease. Rowntree, Marshall and Chesney emphasized the difficulty of interpretation in such studies and called attention to the accompanying changes in the blood. They found that the proportion of blood urea was slightly decreased in hepatic disease. More recently, Bollman, Mann and Magath have reported evidence pointing to a cessation of urea formation in dogs after complete extirpation of the liver. In man, a comparable degree of hepatic insufficency is not observed, even with the grossest hepatic changes. In experimental animals with obstructive jaundice, Greene showed that there was usually a sharp and definite decrease in both the relative and absolute values of the blood urea. These low values persisted until shortly before the death of