"Force fluids" has come to be a therapeutic maxim with the medical profession. For a patient with almost any acute condition, whether it is infection, toxic absorption or surgical shock, the sovereign remedy in most clinics is more water. There is quite a large group of patients who are, for the time being, unable to take liquids satisfactorily by mouth or by rectum, or for whom these routes of administration are too slow. In such cases, a method of administering large amounts of liquid directly into the blood stream slowly and with sufficient safeguards is of great service. The method presented was worked out at the suggestion and with the helpful criticism of Professor Whipple. It provides for automatic control of the rate and temperature of the infusion and makes it possible to observe, at frequent intervals, the recipient's venous pressure, the all important index of his reaction to infusion.