Continuous records of temp. were made in dogs subjected to marked diuresis for 4-7 1/2 hrs., and at the same time detailed studies of metabolism were carried out to correlate changes in body temp. occasioned by injection of sugar with degree of water loss, the quantitative change of certain metabolites in the blood, and the amount excreted in the urine. Marked hyperpyrexia did not occur when all possible toxic factors connected with preparation and administration of the solutions of sugar were excluded. A moderate increase in body temp. bore no direct relation to sugar injected, whether saccharose or glucose. Neither was there any absolute relationship between rise in temp. and amount of water lost. The condition in the urine produced by an excessive intake of water, such as a decrease in the H-ion conc. and in the amount of ammonia and P, is similar in many respects to that after diuresis, as is the fall in concentration of urea and chloride with an increase in total output. The output of fixed inorganic base in the urine, as evidenced by the amount of Na and K excreted, was usually increased. There was always evidence during water loss of a decrease in volume of circulating blood. When glucose was injected, the period of maximal level in the blood corresponded to the period of maximal excretion in the urine. During the period of water loss the blood sugar gradually fell to normal, while the amount excreted in the urine was very small. During diuresis urea output increased with a fall in plasma concentration. With establishment of marked water loss, the plasma content rose and the amount in the urine fell. At the height of water loss in the plasma there was an increase in the plasma chloride and marked decrease in urine content, whereas with restoration of water equivalent to that lost, the plasma chloride showed a decided decrease but the urine content remained extremely small. N. M. Keith.