The search for clinical evidence of endocrine imbalance in juvenile diabetes has become imperative because the results of present day physiologic research indicate that experimental diabetes is a disturbance of endocrine regulation. The importance of these investigations rests not only with the fact that from the combined data of the laboratory and the clinic the mechanism of diabetes may be explained and its cause and prevention indicated but also with the possibility that a more nearly perfect form of treatment may be developed. The physiologist's point of view has been summarized by Houssay1 in a classic article entitled "Diabetes as a Disturbance of Endocrine Regulation," published in 1937. He has defined diabetes as a disturbance of carbohydrate metabolism in which the normal balance of regulating factors is altered. The muscular disturbances are secondary to functional changes in the liver and in the hormonal output of the pancreas, the pituitary