4. Glucose and lactose solutions inhibit abomasal emptying as well as acid production.5. Sodium chloride and sodium bicarbonate of low concentration, near isotonic with blood plasma, stimulate abomasal emptying but the bicarbonate is most effective. Hypertonic solutions of these salts inhibit abomasal emptying.6. Pepsin secretion in the abomasum of the calf is not affected by test meals of glucose, lactose, sodium chloride or sodium bicarbonate.7. These results shows a great similarity between the physiology of the abomasum of the milk-fed calf and the simple stomach. This suggests that the same duodenal receptors, discussed by Hunt & Knox (1968), which control gastric movement in man are also effective in controlling gastric emptying in the milk-fed calf.

1. The abomasum of the milk‐fed calf has been examined using an adaptation of the Serial Test Meal method devised by Hunt & Spurrell (1951). The emptying process, acid secretion and pepsin secretion were studied. 2. Using serial test meals of simple solutions instilled into the abomasum via a cannula, our investigation leaves no doubt that the osmolarity of the abomasal contents significantly modifies the rate of abomasal emptying. 3. Hypotonic and isotonic solutions of sodium chloride and sodium bicarbonate increase abomasal emptying but bicarbonate is most effective. 4. Increasing the concentration of solutes in the abomasal contents slows abomasal emptying. Sodium chloride, sodium bicarbonate, ammonium chloride and urea do not delay abomasal emptying until hypertonic concentrations are attained. Hypotonic solutions of potassium chloride, calcium chloride, glucose, lactose, hydrochloric acid and acetic acid delay abomasal emptying. 5. The results obtained in the calf show that the abomasum is under restraint probably from duodenal receptors as is the simple stomach (Hunt & Knox, 1968) and that an osmoreceptor as postulated by Hunt (1956) is an important factor in this mechanism. 6. Acid secretion is inhibited when hypertonic solutions are instilled into the abomasum. 7. Pepsin secretion is not affected by simple solutions in the abomasum. 8. Gastric function in the milk‐fed calf appears to be controlled by mechanisms essentially similar to those already demonstrated in the simple stomach.