GENERAL METABOLISM. 



633 



From these values it is apparent that the starving man quickly adjusts 

 himself to a definite minimum consumption. 



In the further duration of the fasting period the organism lives exclu- 

 sively at the cost of its protein and its stores of fat. The carbohydrates 

 are quickly consumed, and in the later periods come scarcely into 

 consideration at all. The starving organism is very economical with its 

 protein. Of the total calories 84 to 90 per cent come from the fat, and 

 only from 10 to 16 per cent from protein. This holds naturally only for fat 

 animals. After a time th^ stores of fat are exhausted, and the organism is 

 then compelled to obtain the requisite amount of energy (calories) at the 

 expense of its own protein. At this time there is a rapid increase in the 

 elimination of nitrogen through the urine. This was observed by Voit, 1 

 and has subsequently been much discussed. As a matter of fact, the 

 animals experimented upon were found to be not entirely free from fat at 

 the time when, just before death, there was an increased elimination of nitro- 

 gen in the urine. Often quite a considerable amount of fat has been 

 found to be present at such a time. On account of this fact the conclusion 

 has been drawn that the increased elimination of nitrogen is not 

 altogether due to the fact that the store of fat has been entirely con- 

 sumed, but that there must be other causes. F. N. Schulz 2 assumes 

 that the increased decomposition of protein just before death by starvation 

 is to be attributed to the sudden destruction of numerous cells in the body. 

 It is indeed conceivable that the cells, whose ability is taxed to the 

 utmost during starvation, in order to provide the necessary material for 

 the general metabolism, at last disintegrate. They are constantly giving 



1 E. Voit: Z. Biol. 41, 113, 502, 550 (1901). 



3 F. N. Schulz: ibid. 41, 368 (1901), and Pfliiger's Arch. 76, 379 (1899). 



