Pigment of Anthracosis

Abstract

Black pigment of the human lung, from the time of its earliest observation, was considered to be a collection of coal particles. Pearson in England first applied the term anthracosis in 1813. In Germany, on the contrary, this view was combatted and as late as 1855 Barthelmess discussed the condition as “pulmonary melanosis” and thought it was the result of hemorrhage and inflammation. By 1867 there was general agreement that the pigment was inhaled coal or soot. Klotz 1 has reviewed the subject. No modification of that view appeared until 1940. Then Woodruff 2 and Moerke 3 reverted to the old opinion that the pigment is endogenous. Their pigment was isolated by dissolving the tissue in concentrated hydrochloric acid at room temperature—a procedure known to produce abundant humin in the hydrolysis of protein at the boiling point.

In the present experiments, both clean (calf) and anthracotic lungs (human) were examined for pigment by solution of the tissue in the above solvent as well as in alkaline hypochlorite and by a combination of papain digestion followed by hypochlorite. Only these latter methods sufficed to reduce the clean lung tissue to a negligible residue.

Destruction of uncontaminated lung in concentrated hydrochloric acid left a residue which was soluble in neither organic solvents nor dilute alkali. It was dark red-brown in color, contained 8-10% N in different preparations and 1-1.2% ash. The material of Moerke contained 4-5% N and presumably was a mixture of the above product with anthracotic pigment. As there was no black pigment to be seen in the microscopic examination of the calf lung, the residue is obviously an artefact resulting from the process of digestion of the tissue, and the hydrochloric acid method is not satisfactory for the isolation of the pigment of anthracosis.