THE LAWS OF ENERGETIC EXPENDITURE 185 



cumstances progressively decreases until the third and fourth 

 hour. 



2. The initial rise increases until the third hour if the diet is 

 nitrogenous. 



3. In consequence of 1 and 2 a carbo-hydrate diet is more 

 economical than an nitrogenous diet, the materials of the first 

 being more quickly utilised than those of the second ; 



4. All things being equal, the expenditure, in nitrogenous 

 foods, is greater than the expenditure in carbo-hydrates. Briefly 

 stated, a day's work with a carbo-hydrate diet is 4-5% more 

 economical than with nitrogenous diet.f 1 ) The difficulty of 

 feeding for several days on fats makes any experiments with these 

 impossible. 



128. Conclusions and General Laws. 



1. Work compared to the simple support of a load necessitates 

 a higher energetic expenditure in the same time, and motive work, 

 other factors, being constant, is more expensive than resistant 

 work. 



2. An economy of expenditure is attained by working quickly 

 that is, by dividing the loads into fractions and taking short and 

 frequent rests. 



3. Movements of great amplitude are more economical than 

 those of small amplitude, more often repeated. There is a 

 rhythm which gives best results for a day's work. 



4. In a given time, a maximum amount of work will be pro- 

 duced if the resistance to be overcome decreases progressively, 

 that is, if the sensation of fatigue itself regulates the effort of the 

 muscles. 



5. Carbo-hydrate alimentation leads to an economy of 4-5% per 

 day in the expenditure of energy, as compared with a nitrogenous 

 diet. 



6. The law of repose must regulate the duration of the intervals 

 of repose in the course of the working day in accordance with the 

 demands of various trades. This is a fundamental principle, 

 but it has not yet been much studied. 



The application of the six preceding laws to the scientific 

 organisation of industrial work allows a man to utilise his 

 muscular force to the best advantage without prejudice to his 

 intellectual capacity, always a great asset. It prevents him 

 from overstepping the physiological limits of normal activity. 



(*) Jules Amar (Comptes Rendus Acad. Sc., 1912, 19th Feb., p. 528 ; 

 Journal de PhysioL, 1912, p. 298). 



