ETIOLOGY During the last thirty years, investigators have, at one period or another, announced the discovery of the cause of recurrent vomiting—uric acid diathesis, autointoxication, gastric neurosis, hysteria, chronic appendicitis, postural defect, eyestrain—to name a partial list; yet the real cause is still undiscovered. What is meant by recurrent vomiting? If one should attempt to define it, the definition becomes a description of the disease; if one should attempt to diagnose it, the diagnosis must exclude all other causes of recurring attacks of vomiting. Scarcely ever can one say after a single examination, "This is recurrent vomiting, and nothing else." Yet the picture of the disease with its constantly repeated attacks is a definite one. In 1901, Marfan1described a series of cases, in which there were recurring attacks of vomiting with the early appearance of acetone bodies in the urine and expired air. These cases were identified