To the Editor: The article by Rizza et al. in the December 4 issue* is exciting in its implications for the control of blood sugar. However, in terms of practical application, it raises several questions. First of all, when diabetes is “out of control” and patients come into the hospital for determination of insulin dosage, the amount of insulin needed initially to bring the disease under control can be much different from the amount needed to keep it under control on a longer-term daily basis. The questions remain, therefore, of whether the Biostator could be used to normalize blood sugar. . .