230 THE HUMAN MOTOR 



As the surface of an adult is 19,900 square centimetres approxi- 

 mately, the loss will be : 



Q= 85450 Cal. (37-50C - t) 



in an external environment of t. This formula should be re- 

 membered. 



166. Examples. Let there be an environment at 9C. Re- 

 placing t by 9C in the expression for q we have : 



Q = 2435 Calories. 



At this same temperature, Jules Lefevre ( l ) measured a total 

 of 3,216 calories. From which we can infer a physiological 

 expenditure of 781 Calories, independent of the thermic influences 

 of the exterior. 



Let / = 20C (as in the American experiments) . Then : Q = 

 1,496 Calories, which gives: 



1,496 + 781 = 2,277 Calories. 



as the total static expenditure, of which about f are expended in 

 the regulation of the temperature. 



In a hot environment (in the tropics) at 37-50 C. we have 

 37-5 1 -- O ; the loss being zero and the organism reduced 

 to its minimum expenditure of energy. Further, suppose a 

 temperature, t, higher than 37-50 C. The organism would not 

 gain by it, because outside its thermic regulation, it could not 

 employ the heat for any physiological service. On the contrary, 

 it is a source of embarrassment, owing to the excessive per- 

 spiration which results (Rubner's Physical Regulation, 108). 



Some special examples are interesting. In the case of children 

 as their surface is relatively large, the calorific loss is relatively 

 higher than in the adult. Very thin people experience, for the 

 same reason, an excessive loss, to which they respond by more 

 calorific production. Fat men, on the contrary, have a relatively 

 small surface. Nevertheless, the intensity of their combustions 

 does not suffice to cover the necessary expenditure, and it is the 

 same with emaciated subjects with very little muscle. 



167. Other Effects of Temperature. It has been recognised 

 that the contractions of the muscles become rapid and energetic 

 in an environment of + 20 C., and that at this same temperature 

 the resistance to fagitue is a maximum. ( 2 ) In addition, cellular 

 renovation is accelerated between + 37 C. and + 40 C. 

 Directly opposite effects are observed at low temperatures. ( 3 ) 



( l ) Bioenergetique, p. 405. 



( 8 ) J. Carvallo (Comptes Rendus A cad. Sciences, vol. cxxx, 1900). 



() R. Penzo (Arch. p. le Sc. Med., vol. xvi., p. 129, 1892) ; Bizzozero 

 and Sacerdotti (Giomafe della R. Acad. d. Med. di Torino, vol. lix. No. 5, 

 1896.). 



