Acidity at different sites in the proximal duodenum of normal subjects and patients with duodenal ulcer.

Rhodes, Apsimon, and Lawrie (1966) have recently measured pH in the duodenal bulb for long periodsl* using two glass electrodes. By this method it is possible to maintain the distal electrode within the duodenal bulb for long periods but its exact position in the bulb cannot be determined. Over short _.... periods of time, however, the electrode can be located accurately by radiological methods. In this paper we describe the results of short-term observations on duodenal pH in normal subjects and patients with duodenal ulcer.