156 THE HUMAN MOTOR 



This table shows clearly that the work has raised the expendi- 

 ture, and that after its cessation the return to a state of repose is 

 gradual (see 128). The speed of the vital reactions does not 

 resume its initial value immediately on the cessation of work. 



Compared with a litre of oxygen, the total energy is 

 5,176-20 X 1429 



1,558-80 *75Cd. 



This calorific power differs a little from that which was ob- 

 tained in repose. The American professors obtained an average 

 value of 4-90 cal. ( 110). 



The heat carried away by the vapourised water (from the 

 luners and skin) represents : 



1 952 1 S 

 3,297-60 X 0-592 Cal. , = 1,952-18 Cal. or ^1^0 = 37 ' 7% f 



the total expenditure. This proportion varies with the intensity 

 of the labour, but not altogether regularly. 



Deducting the static expenditure (2,397 Calories) from the 

 5,176-20 Cal. expended in performing work amounting to 603-80 

 Calories, the dynamic expenditure will be 5,176-202,397 = 

 2,779-20 Cal. 



The motive work is therefore only a small fraction : 



603-8 

 27779^2 " 



The temperature of the body during the work, varies some- 

 times 1C ; but, whilst the stay in the calorimetric chamber 

 raised the temperature of the man in repose by 0-03C in 

 twenty-four hours, it lowered it by 0-06 C C during the working 

 periods ; for the temperature tends to fall after work.f 1 ) 



Finally, it is seen that a ration producing 5,176-20 Calories is 

 needed when the work is equal to 603-80 Calories or 260.000 kilo- 

 grammetres, the maximum which can be accomplished by work- 

 men, with very rare exceptions. 



106. Examples of Beneficial Combustibles used by Animated 

 Motors. The alimentary ration is generally mixed ; the reserves 

 of the body, the source of its energy and its expenditure are, 

 therefore, a mixture of fats, proteids and carbo-hydrates. None 

 of these typical substances could serve alone as the exclusive 

 source of energy. The living motor requires at least 65 grammes 



reached 7 '73 kg. A complete description of this bicycle has been given 

 by Benedict and Cady in Publication, 167, of the Carnegie Institute, 

 Washington, 1912 (not to be confused with the Bulletin). 

 (*) Atwater and Benedict (Bulletin, No. 136, p. 154, 1903). 



