THE term “cyclic vomiting” is frequently encountered in pediatric literature and often appears to be applied to cases in which the vomiting is not periodic, so that some other term such as “recurrent” or “reflex vomiting” would be more accurate. The earlier descriptions of cases of cyclic vomiting were published long before the advent of the roentgen ray. Gruère (1) was one of the first to describe this condition, in an article published about 1840. Since then, systematic use of the roentgen ray in the examination of digestive disturbances in infants and children has thrown considerable light on the subject. In our experience in the examination of several hundred children, the cases of cyclic vomiting have usually been associated with lesions outside of the stomach itself. Hence the term “reflex vomiting” would be an advisable term to apply to this type of case. Griffith (2) called attention to the incorrectness of the term “cyclic” and suggested substituting for it “recurrent,” since “the word ‘cyclic’ implies a certain regularity which is not a characteristic of the disease.” Marfan and other French authors called the condition “acetonemic vomiting.” A number of other authors have considered the condition as a manifestation of acidosis. On the other hand, a number of pediatricians had about abandoned the theory when a recent contribution along this line was presented by Dr. S. A. Levene (3) under the title “Ketogenesis in Children as Compared with Adults.” Levene has worked out an elaborate formula2 regarding the relationship between fatty acids and glucose, and the production of ketosis in children. So the question of the relationship between acidosis and cyclic vomiting has been reopened. Edsall and Pearson (4) state that they believe in acidosis as a cause for cyclic vomiting. Comby (5), in 1905, thought that the vomiting depended in many instances upon chronic appendicitis. Dr. Mefford Runyon (6) considered chronic appendicitis as a cause for cyclic vomiting, and reported a group of cases. Dr. McGuire Newton (7) has expressed himself as convinced that chronic appendicitis is a competent cause for the condition, and gives great credit to the value of the roentgen ray in making a differential diagnosis. The latest contribution. is by Dr. A. L. Gray (8), who read a paper before the American Roentgen Ray Society in September, 1925, in which he reported a group of cases where removal of the appendix was followed by immediate relief, and he calls attention to the inaccuracy of the term “acidosis” in relation to cases in which the presence of chronic appendicitis is, in his opinion, the cause for the vomiting. Gray calls attention to the absence of pain or distress in the region of the diseased appendix in children.