134 THE HUMAN MOTOR 



It is in this sense that the saying of Claude Bernard is true ; 

 " The muscle is a machine in perpetual renovation," ( J ) and the 

 words of Chauveau : " It is not what one is actually eating that 

 furnishes the energy employed in the physiological work of the 

 organism, but the potential energy formed by what has been 

 eaten previously. "( 2 ) The fact that the bodily organism is, 

 relatively, independent of the food which it is, at the moment, 

 assimilating, has important results. It ensures regularity of work, 

 and makes possible an even tenor of existence, while irregularities 

 in the supply of its fuel (food), which would cause irregular work- 

 ing or complete stoppage in the case of an inorganic heat engine, 

 have no such effect on the human motor. 



The previous elaboration of the aliment, without which there 

 is no real nutrition or energy, and its utilisation afterwards, is 

 what has been designated by the expression : "Labour or physio- 

 logical energy" (Chauveau). Physiological labour includes all 

 the reactions of life, whatever may be the state of the muscles, 

 in repose or in activity. In man, this profound intimate labour, 

 demands the conditions already denned for living matter in 

 general ( 65) : heat, oxygen, moisture, aliments. 



The temperature of the body is assured by the exothermic 

 phenomena of the organism, whose action it assists reciprocally. 



The blood is the vehicle of the oxygen, with which it is charged 

 at the lungs. 



The body of man contains about 60% of water and loses 2 to 3 

 kilogrammes of water per day, in repose. Lack of water may 

 be a grave danger, and lead to respiratory, cardiac, and often 

 nervous trouble. ( 3 ) 



Besides the aliments the organism needs " mineral salts," 

 especially Sodium Chloride. 



The latter regulates the concentration ot the organic liquids, 

 provides the gastric juice, with its acid property, and aids the 

 water to preserve the elastic state of the tissues. The " alkaline 

 salts " (phosphates, carbonates) consolidate the skeleton during 

 its period of growth, and participate in the physico-chemical 

 phenomena of life. The insufncienc}^ or absence of salts (mineral 

 inanition) produces grave illnesses, which affect the nervous 

 system. ( 4 ) Finally, other mineral bodies such as iron manganese 



(*) Cl. Bernard, Les Phlnomenes de la Vie Communs aux Vegetaux et aux 

 Animaux, vol. ii., pp. 506-509, 1879. 



(*) A. Chauveau, La Vie et I'Energie chez I' Animal, p. 50, 1894. 



(*) Pernice and Scagliosi (// Pisani, part ii., 1896). 



(') I. Forster (Arch. f. Hygiene, 1886, and Zeitsch. f. BioL, vol. ix., 

 pp. 297 and 381.) 



