1. We have shown that a test meal of orange juice stimulates a high free gastric acidity which reaches its acme one hour following ingestion. 2. We have shown that orange juice remains in the stomach on an average of one hour and forty-five minutes following its ingestion. 3. We do not yet know what would happen to gastric acidity if an ordinary small glass of orange juice were taken once a day in addition to an ordinary breakfast. 4. We do not know yet how important it is to withhold orange juice in ordinary portions in the treatment of patients with ulcer.