12 ANALYSIS OF DISTURBANCES OF METABOLISM 



food whose heat-equivalent is not decidedly above the interchange of forces 

 in the starving organism does not increase the total metabolism, and with a 

 diet beyond the amount required by the needs of the body the introduction 

 of extra N-free material (fat and carbohydrates), no matter how great, in- 

 creases the interchange of energy only to a certain percentage of the excess 

 of food. 



If the surplus is introduced in the form of fat, only 10.7 per cent, of it 

 undergoes combustion; therefore almost 90 per cent, is deposited as fat in 

 the body. If superfluous carbohydrates are introduced, only 15.9 per cent, 

 goes to increase the total metabolism; 84.1 per cent, is accumulated in the 

 body and is utilized for fat formation, since the body's capacity to increase 

 its carbohydrate material (glycogen deposit) is a limited one.^ 



Since the amount of metabolism is relatively independent of variations in 

 the ingestion of nourishment, we have the conditions which make possible a 

 deposition of fat. 



With an abundant introduction of albumin, however, proteid decomposi- 

 tion increases in exact ratio to the superfluous amount of albumin ingested. 

 The entire superfluous supply is taken up in metabolism, and the N-exeretion 

 in the urine shows a height corresponding to the increased administration. 



In reality it is, of course, only the N-containing complex in albumin which 

 is excreted, and these products of excretion are at once thrown ofE. Of the 

 non-nitrogenous components which remain after excretion, as well as also 

 the superfluous fat and carbohydrates introduced, only a portion is subjected 

 to decomposition, if the organism does not require them to meet its energy 

 requirements, while a considerable remainder (69.1 per cent.) is stored up in 

 the body (fat formation from albumin). Only the elimination of nitrogen is 

 complete. 



For this reason albumin occupies an exceptional position among food sub- 

 stances; the organism requires it for its simple material maintenance. It is, 

 therefore, difficult to understand why the organism should waste so much of, 

 and so soon eliminate, this most valuable food product. 



A number of explanations for this apparent waste have been offered. It 

 has been assumed that owing to the circulation of albumin products in the 

 fluids after albumin nutrition, the individual food stuffs take part in the 

 total metabolism. On the other hand, a special chemical affinity of the cell 

 substance for the individual food products has been assumed owing to the 

 fact that the albumin is most readily absorbed, less speedily the carbohydrates, 

 and last of all the fats. 



Eubner ' has lately assumed that the divisibility of the individual food 

 stuffs explains the different share taken by each in the processes of metabo- 

 lism. These differences in divisibility have not been sufficiently considered 

 until now : " A measure of these differences is the size of the molecules. In 

 the case of fat this amounts to 870, in grape sugar, to only 180. In what 



1 This increase in metabolism by introduction of food was formerly explained by an 

 increase of intestinal activity. Lately the correctness of this view has been doubted. 



2 Rubner, " Handbuch der Ernahrungstherapie," Bd. i, p. 78. 



