Hanriot and Richet1 showed the even absorption of oxygen and elimination of carbon dioxid during the early days of fasting in man, as is illustrated in this table:

Later Lehmann and Zuntz2 made some experiments on the professional faster Cetti. They analyzed his urine and feces, and also obtained two samples of the carbon dioxid eliminated between 10 and 11 A. m., each period of collection lasting from ten to fourteen minutes. In other words, the carbon dioxid output was determined for only twenty to twenty.six minutes daily. From these data the total day's metabolism was calculated. This apparatus as used by Zuntz has the advantage that it can be made in portable form, and may be carried on the back in mountaineering. The person inspires through a mouth.piece provided with a plate of hard rubber which fits between the lips and the teeth. The nostrils are closed with a clamp. The inspired air is drawn through a valve and the expired air is forced through another valve to a gas.meter. Arrangements are also provided for the gas analysis of portions of the expired air. Trustworthy results are obtained only when the person under investigation is accustomed to the apparatus. It is of especial value when pronounced temporary variations in the metabolism are to be measured.

1 Hanriot and Richet: "Comptes rendus de l'Acad6mie des Sciences," 1888, cvi, 496.

2 Lehmann and Zuntz: "Arch f. pathol. Anat.," 1893, cxxxi, Suppl., 23.

The record of the metabolism of Cetti during a ten days' fast was as follows:

Metabolism Of Cetti In Starvation

A very careful experiment on the metabolism of a fasting medical student twenty.six years old was made by Johansson, Landergren, Sonden, and Tigerstedt.1 The man fasted five days, doing light work in the respiration apparatus. The metabolism during these days was determined. The excreta in grams were as follows:

1 Landergren, Sonden, and Tigerstedt: "Skandin. Archiv fur Physiologie," 1897, vii, 54.

Metabolism Of J. A. In Starvation

The evenness of the carbon and nitrogen elimination is remarkable. From the above figures the following table of the general metabolism is made:

Further calculation shows the following relations between the weight of the individual and the calorific production:

On the fifth day of fasting it is seen that the individual oxidized 71.7 grams of protein, 181.2 grams of fat, and produced 1971 calories, or 31.23 calories per kilogram of body substance. This is presumably the minimum compatible with ordinary life.

Reference has already been made to the notable work of Benedict (p. 72), "The Influence of Inanition on "Metabolism".

Here in seventeen experiments on seven men the metabolism was determined during a fast of two days, and in one instance the starvation period extended over seven days. In these experiments the metabolism of glycogen was for the first time determined. Benedict's fasting individuals were placed in a respiration calorimeter, and in addition to the usual routine the amount of oxygen consumed by them was measured. Knowing the last factor, Benedict was able to calculate the amount of glycogen destroyed by deducting from the total oxygen intake the part necessary to oxidize the protein catabolized, and then, in the light of the knowledge of the respiratory quotient, apportioning the remainder of the oxygen to the non-protein carbon dioxid eliminated in such a way as to indicate the amounts of glycogen and fat destroyed (see p. 60). The heat value of the metabolism thus calculated agreed within ½ of 1 per cent, with the heat as actually measured by the calorimeter in which the man lived, whereas if the nonprotein carbon of the first day had been reckoned as fat metabolized, as had heretofore been the custom, the discrepancy would have been as high as 5 per cent, in some instances. This shows the usefulness of a comparison of direct and indirect calorimetry (see p. 57).

The results of Benedict's experiment on an individual who fasted for seven days are here reproduced:

Metabolism Of S. A. B. During A Seven-Day Fast

This complete and recent experiment reaffirms the principles which have already been enunciated. Benedict found that the pulse.rate showed a distinct tendency to fall. In the above individual the average pulse.rate was 57 on the first fasting day and 51 on the seventh day.

E. Voit1 gives the following summary of the energy requirements during the early days of starvation in man:

General Table Of Starvation Metabolism In Man

To this may be added the average results of the many experiments by Benedict:

Metabolism In The Early Days Of Starvation

This minimal metabolism requirement of the fasting organism appears remarkably constant in different men. Not only is the total metabolism the same, but also the amounts of protein and fat which yield the energy are the same. This is shown by comparing the nitrogen excretion of the different fasters during the first days of fasting. These are as follows:

1 Voit, E.: "Zeitschrift fur Biologie," 1901, xli, 114. 2 Munk: "Arch. f. Path. Anat.," 1893, cxxxi, Suppl. 25. 3 Munk: Ibid., p. 68. 4 Luciani: "Das Hungern," 1890.

5Johansson, Landergren, Sonden, and Tigerstedt: "Skandin. Archiv. fur Physiol.," 1897, vii, 54.

6 Freund, E. and O.: "Wiener klinische Rundschau," 1901, xv, 91.

It is thus evident that if the organism has previously been well nourished, the fasting metabolism is remarkably even, about 13 per cent, of the total energy being derived from protein and 87 per cent, from fat.