“…In addition, the period of treatment has usually been relatively short, which makes the evaluation of late results difficult. Some early reports drew attention to failure of treatment after prolonged administration (Heinsen and Hagen, 1956;Engelhard, 1956;Brechman, 1957;Mohnike et al, 1957;Pfeiffer et al, 1957;Dotevall, 1958). These so-called late failures have often been attributed to neglect of the diet, unsuitability of the patient for oral treatment, infections (Bertram, 1958), or similar causes.…”