140 APPENDIX II. 



also possible that muscular work may be derived 

 from the oxidation of the food, which has only 

 arrived at the condition of blood and not of or- 

 ganized muscular tissue. 



The importance of this problem can scarcely be 

 overrated ; it is a corner-stone of the physiological 

 edifice, and the key to the phenomena of the 

 nutrition of animals. For its satisfactory solution 

 the following data require to be determined : 



1st. The amount of force or actual energy gene- 

 rated by the oxidation of a given amount of muscle 

 in the body. 



2nd. The amount of mechanical force exerted by 

 the muscles of the body during a given time. 



3rd. The quantity of muscle oxidized in the body 

 during the same time. 



If the total amount of force involved in muscular 

 action, as measured by the mechanical work per- 

 formed, be greater than that which could possibly 

 be generated by the quantity of muscle oxidized 

 during the same time, it necessarily follows that 

 the power of the muscles is not derived exclusively 

 from the oxidation of their own substance. 



Istly. As regards the first datum to be determined, 

 it is necessary to agree upon some unit for the 

 measurement of mechanical force. The unit of 

 force most commonly adopted is that represented 

 by the lifting of a kilogram weight to the height of 

 one metre. The researches of Joule and Mayer 

 have connected this standard unit with heat ; they 

 prove that the force required to elevate this weight 

 425 times will, when converted into heat, raise the 



