It is well known that anaemia of the Addisonian type is accompanied by an absence of free hydrochloric acid from the gastric juice.In so-called secondary anaemia Davies' found that in the gastric juice there was excess of mucus, low peptic activity and frequently a fixed pH in contrast with the absence of mucus and peptic activity and complete fixation of the pH in pernicious anaemia. Hartfall and Witts' pointed out that in simple -achlorhydric anaemia t-he total chlorine and peptic activity were low when there was a deficient amount of intrinsic factor. Recently Hartfall' has stated that in the same individual free acid may be secreted at one time and not at another. He also considered that the data obtained from infants were unreliable owing to the numerous inhibitory factors likely to interfere with gastric secretion. In twenty-six adult patients with unexplained achlorhydria Polland' failed to find any significant variation from normal in the haemoglobin value and red cell count; he therefore concluded that anacidity per se did not tend to the production of anaemia. Bloomfield and Keefer' as a result of their investigations into gastric secretion in adults decided that anaemia, other than the pernicious type, had little or no influence on the secretion of gastric juice. Hawksley, Lightwood and Bailey6 in thirteen children under ten years of age with simple iron-deficiency anaemia found achlorhydria in twelve, and consider that achlorhydria may be a causal factor. In the literature-there are few' other studies in children of the association of anaemia with defective gastric secretion.During the course of an investigation into the gastric secretion in children, the following results were obtained. Thirty-four anaemic children, twenty-two boys and twelve girls, were examined; the ages varied between five months and eleven years. The method employed in examining the gastric secretion has been described in previous papers7. In children, as in adults, there is wide variation in the concentration of the hydrochloric acid in the gastric juice but for purposes of classification any readings of an acidity above 50 c.c. or below 12 c.c. I" per cent. were considered to indicate hyper-or hypochlorhydria respectively.