“…Coated vesicles and smooth thick vesicles, with or without ferritin, were seen in all cases, as were ferritin aggregates.Ring-sideroblasts have been observed in an increasing number of haematological disorders (Dacie and Mollin, 1966;Hines, 1969). The ultrastructural characteristics of pathological sideroblasts (RSA) have been reported previously (Bessis and Breton-Gorius, 1962;Larizza and Orlandi, 1964;Goodman and Hall, 1967; Petz, Goodman, Hall and Fink, 1966;Tanaka, Brecher and Bull, 1966). The purpose of this communication is to describe and compare the electron microscopic features of erythroid cells$ in patients with 'primary' and 'secondary' types of RSA (Mollin, 1965) and in patients with reversible sideroblastic anaemia associated with severe alcoholism (Hines, 1969).…”