In the article by Dr. Norman Rosenthal, Dr. Sidney P. Zimmerman and Dr. Shepard Shapiro entitled "Prothrombin Level of Peripheral Blood and Sternal Marrow" in the April issue (Arch. Int. Med.77:420, 1946), "not" was inadvertently inserted in the first paragraph of the "Conclusions." The paragraph should read as follows:
"From the evidence presented we are led to conclude that prothrombin is not elaborated by the reticuloendothelial system and therefore is probably a function of the hepatic parenchyma."