290 ANNUAL OF SCIENTIFIC DISCOVERY. 



convert one gramme of dry muscle into urea, as much heat was 

 evolved as would, when converted into mechanical force, be suf- 

 ficient to raise a hundred weight to the height of one hundred and 

 tliirty-two fc^et. 



The second of the required data, viz., the actual work performed 

 in a given time by the muscles, Avas ingenimisly determined by 

 Fick and Wislicenus by the elevation of the body itself. For this 

 purpose they ascended the Faulhorn, a mountain of tlie Bernese 

 Aljjs, 6560 feet high, near the lake of Brienz, whose regular slopes 

 rendered it well adapted for their experiment. The height of the 

 mountain, multiplii'd by the weight of the l)ody of each experi- 

 menter, gave the ara(nuit of external work performed, and to this 

 was added the estimated internal work of the circulation and res- 

 piration. 



The third datum — the amount of muscle consumed — was given 

 as a maximum by the amount of nitrogen excreted by the kidneys. 

 This amount being determined by analysis, the amount of muscle 

 consumed is readily calculated, since every 15.6 parts of nitrogen 

 indicate 100 parts of muscle destroyed. The excreted nitrogen 

 was determined in the experiments of Fick and Wislicenus with 

 every possible care ; and in order that there might be no soui'ce 

 of loss, tlie amount excreted for six hours after the ascent was 

 taken into account. 



As a tinal result of their investigations, they found that the mus- 

 cle consumed, even with the most liberal allowance for all possi- 

 ble chanc(i of error, would not account for the work performed. 

 Even under the most favorable interpretation, and neglecting all 

 the internal and external work that could not be accurately meas- 

 ui'ed, it was found that the eomljustion of the muscles themselves 

 would not account for a third of the work performed. 



The calorimetrical determination of the actual energy evolved 

 by the combustion of muscle and of urea in oxygen have been 

 made by Dr. Frankland; and the results show that the amount of 

 muscle destroyed by the former gentlemen during their ascent 

 would not account for one-half of the force i-eipiired to lift them to 

 the summit of the mountain. Taking the average of the two ex- 

 periments, and making several necessary allowances. Dr. Frank- 

 land calculates that scarely one-fifth of the actual energy required 

 for the Avork performed could be obtained from the amount of 

 muscle consumed. 



Examining a number of pi-evious experiments of a like kind. 

 Dr. Frankland finds them all confirmatory of the same thing. Thus, 

 he gives a summary of three sets of exjjeriments made by Dr. E. 

 Smith, by the Rev. Dr. Haughton, and by Playfair, in which in 

 each case the force expended is in excess of that derivable from 

 the muscle oxidized. 



The following are the conclusions deduced by Dr. Frankland 

 from his exi^eriments : — 



" 1. The muscle is a machine for the conversion of potential 

 energy into mechanical force. 



"2. The mechanical force of the muscles is derived chiefly, if 

 not entirely, from the oxidation of matters contained in the blood, 

 and not from oxidation of the muscles themselves. 



