SCIENCE AND MAN 867 



velocity of 80 feet to an 8-lb. ball consumes in the act tV 

 of a grain of carbon. The lieat of tbe muscle is here dis- 

 tributed over the track of tbe ball, being developed there 

 by mechanical friction. A man weighing 150 lbs. con- 

 sumes in lifting his own body to a height of 8 feet the 

 heat of a grain of carbon. Jumping from this height the 

 heat is restored. The consumption of 2 oz. 4 drs. 20 grs. 

 of carbon would place the same man on the summit of a 

 mountain 10,000 feet high. In descending the mountain 

 an amount of heat equal to that produced by the combus- 

 tion of the foregoing amount of carbon is restored. The 

 muscles of a laborer whose weight is 150 lbs. weigh 64 

 lbs. When dried they are reduced to 15 lbs. Were the 

 oxidation corresponding to a day-laborer's ordinary work 

 exerted on the muscles alone, they would be wholly con- 

 sumed in 80 days. Were the oxidation necessary to sus- 

 tain the heart's action concentrated on the heart itself, it 

 would be consumed in 8 days. And if we confine our 

 attention to the two ventricles, their action would con- 

 sume the associated muscular tissue in 8J^ days. With a 

 fulness and precision of which this is but a sample did 

 Mayer, between 1842 and 1845, deal with ihe great ques- 

 tion of vital dynamics. 



In direct opposition, moreover, to the foremost scien- 

 tific authorities of that day, with Liebig at their head, 

 this solitary Heilbronn worker was led by his calculations 

 to maintain that the muscles, in the main, played the part 

 ■of machinery, converting the fat, which had been previ- 

 ously considered a mere heat- producer, into the motive 

 power of the organism. Mayer's prevision has been jus- 

 tified by events, for the scientific world is now upon his 

 side. 



