Diabetes insipidus is a symptom which may be due to a variety of causes. Its diagnosis and treatment, unsatisfactory as the latter may be, present no difficulty, but the detection of the underlying cause often requires considerable study and may at times be impossible. When this underlying cause is not ascertainable a diagnosis of idiopathic diabetes insipidus may be made. In many instances this classification will be correct, since neither the further course nor the necropsy will reveal an anatomic cause for the polydipsia and polyuria. In other cases the basic process will be recognized only after the symptoms have progressed for months or years.
The observation of a few cases of polyuria and polydipsia and the attempt to formulate their prognoses induced us to study the literature of diabetes insipidus in children. This survey demonstrated that definite progress has recently been made in the understanding of some of the