Large amounts of water are regularly consumed by all individuals throughout life. Since one or more liters pass through the body in 24 hours, it is hardly conceivable that such passage is unaccompanied by energy transformations; the processes of absorption and secretion should also be taken into consideration. Furthermore, the taking of water at various temperatures frequently produces distinct subjective effects and (at times) effects of a physiological nature, such as an inclination to defecation. A study of the question as to whether or not the drinking of water produces a measurable effect on the basal metabolism is therefore of prime importance.

The literature is very deficient in definite information regarding the influence of water-drinking upon the metabolism. The most detailed experiments are those carried out in Rubner's laboratory by Lasch-tschenko,1 who concludes that the drinking of water at room temperature (approximately 18° C.) has no influence upon the carbon-dioxide production. Water at 32° to 33° C. produced a very slight increase, but at 37° C. there was practically no increase in the carbon-dioxide production.

Although the effect of water-drinking on the metabolism was studied by Berg,2 the technique was too unreliable to permit deductions from the experiments. Speck,3 who worked with a much more satisfactory technique in the experiments upon himself, concludes that drinking large amounts of water before an experiment has no influence upon the oxygen consumption or carbon-dioxide production. He found, however, that when 1,250 c.c. of water were taken inside of one hour and observations were begun 30 minutes after the water had been taken, there was a noticeable rise in the metabolism; in this experiment the author noted shivering. He considered that the rise was due to a stimulus of the digestive canal, of which he became aware shortly after taking the water because of the movement of gas in the intestines.

Loewy4 reports that immediately after the ingestion of 100 grams of cold water there was pressure and discomfort in the intestines, which was followed a half hour afterward by a movement of the bowels. The water caused an increase of but 2 per cent in the oxygen consumption with a great increase in the carbon-dioxide production. In his second experiment, in which the same amount of water was given, there was an increase of 1.5 per cent in the oxygen consumption 11 minutes after the water was taken and an increase of approximately 6 per cent 33 minutes after the drinking of the water. Thus Loewy found no definite increment in the metabolism as a result of the ingestion of pure water. Since, however, his technique as a whole has been criticized1 and a duplication of the experiments has not resulted in confirming his original observations, it is not possible to place much emphasis upon his findings.

1Laschtschenko, Arch. f. Hygiene, 1898, 33, p. 145. 2Berg, Deutsch. Arch. f. klin. Med., 1869, 6, p. 291. 3Speck, Physiologic des menschlichen Athmens, 1892, p. 42. 4Loewy, Arch. f. d. ges. Physiol., 1888, 43, p. 525.

Probably no factor makes direct calorimetry so difficult in a study of the effect of food on the metabolism as does the ingestion of liquids, which are almost invariably taken into the body at temperatures considerably below or above the body-temperature. Water is usually taken at a temperature below that of the body, while coffee, tea, and thin extracts or soups are ordinarily taken at a temperature above. The question of the temperature adjustment inside the body is therefore somewhat important. While the rectal temperature gives a remarkably good indication of the average body-temperature, it is by no means certain that the large amounts of heat required to warm a considerable quantity of water from 10° C. to body-temperature may not seriously disturb the temperature distribution. Indeed, in certain experiments reported from this laboratory,2 the ingestion of water produced a noticeable change in rectal temperature. The experience of Rancken, in Tigerstedt's laboratory in Helsingfors,3 shows that the rectal temperature, although instantly affected by the ingestion of cold liquids, returns to its original value in about 30 minutes, indicating that the equalization of temperature is rapid. In a recent series of observations Stengel and Hopkins,4 employing a thermo-couple, found that after the ingestion of 120 c.c. of ice water the temperature of the stomach dropped rapidly 1° to 14° C. and returned to normal in from 19 to 31 minutes.

The experimental difficulties experienced by Lusk5 when giving a dog large amounts of water and meat just taken from an ice chest illustrate very clearly the disturbance in the heat distribution and incidentally the difficulties of determining the heat production by direct calorimetry when a large amount of material is ingested at a temperature considerably above or below that of the body.