Sir.—Bancroft1 asked in his letter if any other pediatricians have observed newborns who developed hypocalcemic tetany while being fed Similac with Iron formula, with resolution of the tetany when switched to a low-phosphate formula. He described such a patient, and he noted the recent report2 of five newborns with tetany fed Similac 20. We observed similar cases in our early studies of this problem, but since we did not identify Similac in the publication,3 Dr Bancroft could not have been aware of this situation. In our report Similac was designated as "cow's milk product II." Our attention was called to Similac in the following way.
In 1947 Walter Pick, MD, and I were preparing a Pediatric Grand Rounds presentation at the Massachusetts General Hospital, Boston, on neonatal tetany when, in tabulating the 16 cases we had recently seen, we were struck by the prevalence of Similac