The incidence and significance of iron-containing granules in human erythrocytes and their precursors.

" siderocyte " to describe erythrocytes containing small granules readily demonstrable by means of Perls's (Prussian blue) reaction. He found these cells in small numbers in the blood of normal rat, mouse, and human embryos (Gruneberg, 1941a and b), and later (Gruneberg, 1942) in large numbers in the blood of mice suffering from congenital anaemia. Doniach, Gruneberg, and Pearson (1943) described the occurrence of siderocytes in adult human blood. They found 15% of siderocytes in a patient with hepatic cirrhosis who had undergone splenectomy, and small numbers (1% or less) in four patients whose spleens had been removed for splenic anaemia, thrombocytopenic purpura, or traumatic rupture. Pappenheimer, Thompson, Parker, and Smith (1945) described the appearance of erythrocyte inclusion bodies in three patients whose anaemia persisted after splenectomy. In two patients the anaemia was haemolytic in type; in the third it was of undetermined type. They found that the inclusions in the erythrocytes stained with Romanowsky dyes as well as giving a positive Perls's reaction; the Feulgen reaction was, however, negative. McFadzean and Davis (1947) extended the observations of Pappenheimer et al. (1945), and referred to the inclusions demonstrable by Romanowsky dyes as " Pappenheimer bodies." Gruneberg (1942), McFadzean and Davis (1947), and Dacie and Doniach (1947) observed that inclusion bodies identical in staining reaction with those seen in