/; AND MAN. 605 



lowever subtly devised, can ova iw of 



equivalence, or perform on its own aceomr 



MIII of work. Ti .mn't 



imal body, tii, -ii. to be classed among 

 \\ hen 1 lift a weight, or throw a sto; 

 climb ;i mountain, or wrestle with my comrade, am 1 n<>t 

 conscious of actually creating and expending !" I 



us look at the antecedents of tin- f>ice. \Vo derive the 

 le and fat of our bodies from what we eat. Animal 

 x now to be din- to the slow combustion of this 

 furl. My arm is now inactive, and the ordinary slow 

 combustion of my blood and tissue is going on. For every 

 grain of fuel thus burned a perfectly definite Amount < 

 has been produced. I now contract my ; .;.-,-ps muscle 

 without causing it to perform external work. The com- 

 bustion is quickened, and tin- heat is increased; t iii- 

 additional heat being liberated in the muscle itself. 1 lay 

 hold of a 5U-lb. weight, and by the con tract ion of my biceps 

 lift it through the vertical space of a foot. The blood and 

 tissue consumed during this contraction have not developed 

 in the muscle their due amount of heat. A Quantity of 

 heat is at this moment missing in my muscle which would 

 raise the temperature of an ounce of water somewhat m<>t< 

 than ce Fahrenheit. I liberate the weight: it 



falls to the earth, and by its collision generates the 

 precise amount of heat missing in the muscle. My mus- 

 cular heat is thus transferred from ite local hearth to 

 external fcpaoa The fuel is consumed iu my body, but the 



>f combustion is product e my body. 



case is substantially the same as that of the voltaic* battery 

 \\heu it performs external work, or produces external beat. 

 All this points to the conclusion that the force we employ 

 in muscular exertion is the force of burning fuel and not 

 of creative will. In the light of these facts the b- 



be as incapable of generating energy \\ithout 

 liture, as the b-.lids and liquids of the vohai- 

 The body, in other words, falls into the category of 



can do with the body all that we have already 



with the battery heat platinum \. mpoae water, 



otize iron, and dell. < t a mi ice.lle. 



n of muscle may be made .oe all them? :' 



as the combustion of zinc m >\ be caused to produce i 



