ALIMENTATION AND THE EXPENDITURE 143 



searches of Eijkmann ( x ) deserve attention, owing to the con- 

 sistency of the results obtained. The average minimum, accord- 

 ing to his experiments, is 1 -20 grammes per kilogramme. 



R. H. Chittenden,( 2 ) taking as his subjects students, gymnasts 

 and soldiers, found that 0-75 grammes sufficed to maintain health, 

 and vigour, and in addition caused an appreciable increase of 

 muscular power. No loss could be found in the weight of his 

 subjects after experiments lasting for several months. 



When the alimentation is vegetable, -7 grammes seems to be 

 sufficient ( 3 ) ; it cannot be said, however, that animal alimenta- 

 tion necessitates a higher rate. In practice an unnecessary 

 amount of proteids are consumed without any useful result. 

 Taken as a whole, the quantity of food, per kilogramme of the 

 weight of the body, needs to be more for tall than for short 

 subjects, ( 4 ) but each maintenance ration should contain about 

 1 gramme of proteids per kilogramme of the weight of the person. 



2. External Environment and Motor Activity. Man, as well as 

 the homeothermic animals, must regulate his temperature at all 

 times, so that it remains practically constant. The probable 

 reason for this is that the speed of the interorganic reactions 

 demands a constant temperature. This latter necessitates a 

 diet of constant calorific value ( 60). 



If, however, the temperature of the " external environment " is 

 reduced the flow of heat from the body will increase ( 1 65) . The 

 supply of heat energy to the organism must therefore be corres- 

 pondingly increased. Thus, as is well known, man needs a larger 

 ration in winter than in summer. 



Normally, and in repose, the organs of digestion, respiration, 

 and circulation are in activity ; and perform internal work, a 

 certain quantity of energy being dissipated into heat. The 

 organism is, therefore, always working, and is maintained in 

 thermal equilibrium by its total expenditure, relative to the 

 external and internal environment, that is, by its " static ex- 

 penditure." In order that the muscles may work and contract, 

 there must be further expenditure to produce this external 

 activity, namely, " dynamic expenditure." The alimentary 

 ration is sufficient for both. 



100. The Evaluation o! the Ration. This can be done in two 

 ways for any given subject and conditions. 



( J ) Eijkmann (Virchow's Arch., vols. cxxxi. and cxxxiii., 1893). 



( 2 ) R. Chittenden, Physiol. Economy in Nutrition, with special reference 

 to the minimum proteid requirement of man in health : an experimental 

 study. London, 1905. 



() L. Lapicque (Arch, de Physiol., 1894, p. 596) ; H. Tissier (Comptes 

 Rendus Biologic, 1910, p. 12). 



(*) Magnus L6vy (Pf tiger's 'Arch.., vol. lv., 1893, p. 1). 



