On the basis of their experiments Howe and Hawk2 conclude that a "repeated fast" is accompanied by less protein loss from the body than an original fast. Thus, in one dog weighing originally 3.4 kilograms, death was threatened after 15 days of fasting, the loss of body weight having been 45.8 per cent. The animal was then given food for forty-seven days and brought back to the original weight, after which it fasted again and lost 46.8 per cent, in weight during thirty days. During the first fast the daily loss of body nitrogen was 2.3 grams and during the second, 1.31 grams.

1 Schulz: "Pfltiger's Archiv," 1906, cxiv, 419-462.

2Howe and Hawk: "Journal of the American Chemical Society," 1911, xxxiii, 253.

The question of what organs are attacked in starvation has attracted attention. Long ago Voit1 showed that the muscles of a cat which starved thirteen days lost 30 per cent., while heart, brain, and cord lost 3 per cent. only. In normally nourished animals E. Voit finds that the relative weights of the fat-free organs in animals of the same species are very constant. He2 uses Kumagawa's3 results to show what percentage the different organs represent in the fat-free organism of a dog before and after a twenty-four-day fast. The third column represents the precentage loss of the fat-free organ in starvation:

Loss In Weight Of Different Organs During Starvation

It is apparent that the greatest loss is from the glands and the least from the skeleton. The activity of the glands is greatly reduced in starvation. Luciani found that there was no gastric juice formed during Succi's thirty-day fast, but Langley and Edkins4 find pepsinogen stored within the cells of a cat's gastric glands. The bile flow continues up to the death of the person, but in diminished quantity, corresponding to the lack of food and the decreasing size of the liver. The writer1 has noticed a great reduction in the activity of the milk secretion in starving goats, there being a permanent cessation of flow after five days. The percentage of fat increases in the milk, as it does in the blood, liver, and other organs.2 The fasting organs attract fat from the fat deposits of the body, and it is brought to them by the circulating blood. Glucose is present in the blood up to the last day of life, having its probable origin in a constant production of sugar in protein metabolism. The composition of the plasma of the blood in fasting, as regards its protein constituents, varies slightly from the normal. Lewinski3 gives the following comparative analyses of blood-plasma of dogs:

1 Voit: "Zeitschrift fur Biologie," 1866, ii, 353.

2 E. Voit: Ibid., 1905, xlvi, 195.

3 Kumagawa: " Aus den Mittheil. d. med. Fakultat der kais. Japan. Univ.," Tokio, 1894, iii, 11.

4 Langley and Edkins: "Journal of Physiology," 1886, vii, 371.

100 C.C. BLOOD-PLASMA CONTAIN OF GRAMS N:

The only constant change seems to be a slight increase of globulin during fasting. Burckhardt believes this to be due to the passage of globulins from the tissues to the blood. Robertson4 reports that in the fasting dog and cat the globulins tend to increase in the blood, whereas in the rabbit, ox, and horse the albumins increase. The percentage of hemoglobin and the number of blood-corpuscles are not appreciably affected. It is evident, then, that the blood in starvation retains the normal composition as regards its nutrient materials, except that it carries fat in increased quantity to the cells. In general the cells are well nourished for the ordinary maintenance of the life functions. Hence the appetite is not an expression of general cellular hunger, but rather the result of a local condition of the gastro-intestinal canal, which stimulates the individual to replenishment.

1 Lusk: Voit's Festschrift, "Zeitschrift fur Biologie," 1901, xlii, 41.

2 Rosenfeld, "Ergebnisse der Physiologic" 1903, ii, 1, 50. 3 Lewinski: "Pfluger's Archiv," 1903, c, 631.

4 Robertson: "Journal of Biological Chemistry," 1912, xiii, 325.

The glycogen of an animal is greatly reduced during starvation, but after seventy-three days it is not entirely removed.1 Prausnitz2 reports that a dog weighing 22 kilograms, after fasting for twelve days and after excreting 287 grams of sugar in the urine as the result of phlorhizin injections, still contained 25 grams of glycogen in his body. The writer3 has found 0.4 gram of glycogen in the liver of a meat-fed phlorhizinized dog after eleven days of diabetes and an excretion of over 600 grams of sugar. Exercise will greatly reduce the glycogen content, but the only method of completely freeing the organism of glycogen is by tetanus.4 Zuntz5 rid a rabbit of glycogen by strychnin convulsions and then kept the rabbit fasting and under the influence of chloral for 119 hours. During this time 5.25 grams of sugar were excreted in the urine, and yet 1.286 grams of glycogen were found in the liver and muscles. This must have gradually arisen from the protein metabolism. The writer6 made an observation that in a fasting diabetic rabbit tetanus produced an extra elimination of sugar in the urine of 1.1 grams, which undoubtedly was derived from the glycogen content of the organism (see p. 458). The quantity eliminated corresponded to the amount found as glycogen by Zuntz, as above mentioned.

There now remains a discussion of the influence of work and of change in temperature upon the fasting organism.

1Pfluger: "Pfluger's Archiv," 1907, cxix, 119.

2 Prausnitz: "Zeitschrift fur Biologie," 1892, xxix, 168.

3 Reilly, Nolan, and Lusk: "American Jour. of Physiol.," 1898, i, 397.

4 Kulz: Ludwig's Festschrift, 1891, p. 119.

5 Zuntz: Verhandl. der physiol. Ges. zu Berlin, "Arch. fur Physiol.," 1893, p- 378.

6 Lusk: "Zeitschrift fur Biologie," 1898, xxxvi, III.