ICTERUS : A RAPID CHANGE OF HEMOGLOBIN TO BILE PIGMENT IN THE CIRCULATION OUTSIDE THE LIVER.

The intravenous injection of red cells obtained from the same animal and laked by distilled water is similar to certain types of hemolysis which result in hematogenous jaundice. This procedure cannot be criticized on the grounds of introducing toxic substances. The hemoglobin circulating in the blood stream is rapidly changed, in part at least, to bile pigment. The change goes on with practically the same rapidity in a normal circulation, in an Eck fistula animal, and in a dog with Eck fistula and hepatic artery ligation. Moreover, the bile pigment formation goes on in a dog whose liver, spleen, and intestines have been shut out of the circulation, and in those with a head and thorax circulation. In the last experiments there had been no operative manipulation of the liver and the bile pigment could not have escaped from the liver and have been absorbed by the circulation above the diaphragm; for example, by the thoracic duct. It is possible that the endothelium of the blood vessels is the agent which brings about the rapid change of hemoglobin to bile pigment. This mechanism probably comes into play when there has been a destruction of many red cells with much hemoglobin free in the plasma. We may conclude that in dogs, at least, hemoglobin can be rapidly changed into bile pigment in the circulating blood without participation of the liver.