Ten subjects were given solutions of 33 mM-trisodium citrate or 505 mM-glucose, by tube into the stomach; either 25, 50, 100 or 200 ml. were instilled. The gastric contents were recovered, after 3 min with the trisodium citrate solution and after 10 min with the solution of glucose, then the stomach was washed out with 250 ml. water. Each volume was instilled six times in quick succession on one day with the trisodium citrate solution, and four times on another day with the solution of glucose. The recovered volume of the original meal, which contained Phenol Red, was assessed from the amount of dye in the combined recovery and wash. Each day's procedure was replicated on three days. 2. About half of the trisodium citrate solution was recovered after 3 min and about half the solution of glucose after 10 min, independent of the volume instilled. 3. Glucose slowed gastric emptying. The effect was seen when amounts as low as 1.5 g passed into the duodenum in 10 min. 4. Within-subject, the volumes of trisodium citrate (a distending gastric stimulus) recovered at 3 min allowed predictions of the volumes of glucose solution (a gastric distending and a duodenal osmotic stimulus) recovered at 10 min. 5. The volumes recovered on one day fell progressively with successive instillations of 25, 50 and 100 ml. 6. The results showed that the control system governing gastric emptying responded to volume and osmotic stimuli even when the intragastric volumes were as small as those in the stomach during the interdigestive periods.
