Changes that occur in the blood in experimental acute gastric fistula are a rise in the carbon dioxide combining power of the plasma, a decrease in chlorides, and an increase in urea. These changes are similar in some respects to those in acute duodenal fistula1 and to those other observers2 have found in high intestinal stasis. In experimental acute gastric fistula there is a greater increase in blood alkalinity, as denoted by the carbon dioxide combining power of the blood, due to the loss of acid from the body through the gastric fistula. The decrease in the chloride content of the blood is quite comparable to that in duodenal fistula and in high intestinal stasis. Studies of the fistulous fluid revealed a loss of chlorides sufficient to account for the decreased chloride content of the blood. Because of the pronounced decrease in blood chlorides and the beneficial results