142 THE HUMAN MOTOR 



99. Maintenance Rations. By suitably increasing or decreasing 

 the quantity of nourishment absorbed in twenty-four hours, the 

 ration which assures " equilibrium of weight " (the body neither 

 gaining nor losing in weight), can be found. " I hold," wrote 

 Boussingault in 1844, " that an ' adult ' animal supplied with a 

 ' maintenance ration ' yields, in the different products resulting 

 from the vital action, a quantity of matter precisely equal and 

 similar to that which he absorbs through the aliments." (*) 

 Hence the weight is constant. The alimentation fills up the 

 gaps made in the reserves by the inter-organic combustion. 



If the alimentation is superabundant, there will be a foimation 

 of other and richer reserves and the person will gain in weight. 



If, on the contrary, it is insufficient, the reserves will make up 

 the deficit and the person will lose weight. The " expenditure " 

 of the organism has a practically constant source ; its value not 

 being modified by the alimentary flux, but, as we shall see, 

 regulated by the energetic flux. In practice, the maintenance 

 ration is easily determined. If the subject lives a regular life it 

 does riot take long to be able to decide it (see Technics, 237). 



Obviously the ration is not the same for everybody. It 

 depends on the total bulk of the body (which varies according to 

 age and sex), also on the external environment and the state of 

 repose or of activity. 



1. The Mtfss of the Body. The necessary alimentary expendi- 

 ture increases with the weight of the body.( 2 ) The wastage of the 

 tissues, the inevitable consequence of life, has first to be made 

 good. This is effected by the proteid elements. The emission 

 of nitrogenous compounds takes place continuously through the 

 urine (in the form of urea and uric acid), through the skin,( 8 ) and 

 by the processes of digestion. The minimum amount of proteids 

 needed to repair this loss is 1 gramme per kilogramme ol the 

 weight of the body, i.e., 65 or 70 grammes for an adult. Pro- 

 vided that the ration be sufficient, ( 4 ) this minimum need not be 

 exceeded. It bears a constant relation to the weight of the body, 

 independent of the activity of the subject ( 5 ) and of the external 

 environment. 



The question of the proteid minimum has formed the basis 

 of a great deal of study for about thirty-five years. The re- 



(!) Boussingault, Economie Rurale, vol. ii., p. 351, 1844. 



( 2 ) A child is in a state of growth ; its ration should therefore be super- 

 abundant (see 81). 



() Moleschott's Untersuch, vol. xii., p. 175, 1879). 



( 4 ) Atwater and Benedict (Bulletin, No. 136, pp. 121^6, 1903). 



() Wait (Bulletin, No. 89, p. 70 ; No. 117, p. 40) ; Atwater and Benedict 

 (Bulletin, No. 136, p.^175). 



