The lowest concentration of total base in the gastric juice was found in patients with hyperacidity and the highest in patients with achlorhydria and in those who had been subjected to gastro-enterostomy. This is true for secretion obtained during fasting and also after stimulation by histamin. Following the use of histamin the curve for secretion of total base is a mirror picture of the curve for total and free acid; as acids go up, total base goes down. The author believes that the study of bases in gastric secretion is as important as the study of acids.