IN 1886, Jaworski and Gluzinski * introduced the generally accepted system of estimating gastric acidity in terms of " degrees." They then pointed out that the subject had been intensively studied for over a hundred years and apologized for adding another communication to the many already published. Forty-six years later, Vanzant and her collaborators 2 called attention to the amazing fact that, despite the enormous amount of investigation, we have not even today any reliable standards of normal acidity for various ages. Their explanation that this gap in our knowledge is due in part to the difficulty of getting a large number of normals for study seems rational. All the previously reported studies of normals were made on comparatively small groups. Bloomfield and Keefer 8 studied 90 " normal" cases in one series and 30 in another. Other studies (Bennett and Ryle, 4 Apperly and Semmens, 5 Dahl-Iversen, 6 Moore et al, 7 Henderson 8 and others), were made on even smaller groups of young individuals, mostly college students. The methods used by various investigators varied widely. The series reported from The Mayo Clinic comprises cases which were considered to be free from organic disease of the gastrointestinal tract, but they were not free from digestive disturbances. It is true that if we consider a person's digestion as normal only when he can eat with impunity anything within reason, in any quantity and at any time, very few people, especially those past middle age, could qualify as normal. The difficulties in studying normal acidity in the human are therefore manifold. Not only is it " not easy to get several thousand normal persons to submit to gastric intubation" (Vanzant et al), but it is doubtful whether any appreciable number of strictly normal persons could be found, particularly in the higher age groups, unless absence of gross pathology is accepted as the criterion of normality. In discussing Vanzant's paper before the American Gastro-Enterological Association, in May 1931, one of us (J. L. K.) pointed out that our figures on gastric acidity collected from office and clinic patients, all of whom complained of gastrointestinal symptoms, corresponded to those of the
