METABOLISM DURING INANITION. 889 



the fact that there is still plenty of non-nitrogenous material (fat) able 

 to be drawn upon. The sudden increase which is sometimes met with 

 after a prolonged period of starvation is due no doubt to the fact that 

 by this time the non-proteid materials of the body, which have been 

 up to that time used for the production of energy by their oxidation, 

 are now practically exhausted, and the whole energy and heat of the 

 body must necessarily be derived from the tissues themselves ; since 

 these are composed essentially of proteid, there is a considerable rise 

 of proteid metabolism. 



The carbon dioxide exhaled from the lungs during starvation con- 

 tinues to be given off in proportion to the weight of the body, to the 

 work done, and in inverse proportion to the temperature of the environ- 

 ment. In a man weighing 71 kilos., Pettenkofer and Voit found that 

 during the first day of fasting 201 -3 grms. C were given off by the respir- 

 ation, and 5*8 grms. by the urine, in which also 12'5 grms. N was elimin- 

 ated. This corresponded to a loss of 78 grms. proteid (370 grms. flesh) 

 and 215 grms. fat. The same man was found by Pettenkofer and Voit 

 to lose, when working on the first day of fasting, 75 grms. proteid (478 

 grms. flesh) and 380 grms. fat. The amount of oxygen taken in in the 

 two cases was 760 and 1072 grms. respectively, and the amount of water 

 exhaled 889 and 1777 grms. Pianke found on the second day of fasting, 

 in a fat subject weighing about 70 kilos., 8 grms. N and 3'7 grms. C in 

 the urine, and 180-9 grms. C given off by the lungs ; corresponding to 

 50 grms. proteid (235 grms. flesh) and 204 grms. fat. 



For a considerable time, as a result of the oxidation of fat and body 

 proteid, the temperature of a fasting animal is maintained to about its 

 normal amount. Towards the end, however, of starvation, the temperature 

 begins to sink, and finally rapidly falls, the meaning of this being that 

 the animal has now practically exhausted all the nutriment which it 

 can take from the tissues, and that the amount of oxidation has become 

 reduced, so that the temperature is no longer capable of being main- 

 tained at normal. The change is also, in part, doubtless due to the 

 fact that the heat regulating functions of the nervous system are 

 beginning to break down in consequence of the deficiency of nutriment. 

 It has been suggested that an animal dying of starvation practically 

 dies of cold ; and it is undoubtedly true that the life of a starved animal 

 can be prolonged considerably by the employment of artificial warmth, 

 since this diminishes the amount of oxidation necessary for maintaining 

 the animal heat, and thus economises the energy-producing substances 

 within the body; but it is, of course, not possible for the artificial 

 warming of an animal to prolong life to any great extent under 

 circumstances of complete deprivation of food. 



Numerous experiments have been made to determine the amount of 

 loss of the several organs and tissues of the body which have occurred 

 during starvation, and also the relative composition of such tissues and 

 organs as compared with those of a well-nourished animal. All such 

 experiments tend to show that the most essential organs of the body, 

 such as the heart and nervous system, live during a period of starvation 

 at the expense of the other tissues. 1 



1 Bidder and Schmidt, " Verdaunngssafte u. Stoffwechsel," 1852; Bisehoff and Voit, 

 "Die Gesetze der Ernahning des Fleischfressers," 1860; Pettenkofer and Voit, Ztschr. 

 f. Biol., Miinchen, Bde. ii. and v. ; J. Ranke, " Die Ernahning des Menschen," 1876 ; Voit, 

 '"Ernaliruiig," Hermann's "Handbuch," 1881, Bd. vi. 



