Prof. Frankland on the Origin of Muscular Power. 187 



bers 378, 326, and 341, agree as closely as could be expected 

 when it is considered that all experimental errors are necessarily 

 thrown upon the calorific value of the potassic chlorate. 



The mean of the above five experimental numbers was in all 

 cases deducted from the actual numbers read off in the following 

 determinations. 



It was ascertained by numerous trials that all the potassic 

 chlorate was decomposed in the deflagrations, and that but mere 

 traces of carbonic oxide were produced. 



Joule's mechanical equivaleut of heat was employed, viz. 

 1 kilog. of water raised 1° C. =423 metrekilogs. 



The following results were obtained : — 



Actual Energy developed by 1 grm. of each substance when 

 burnt in Oxygen. 



It is evident that the above determination of the actual energy 

 developed by the combustion of muscle in oxygen represents 

 more than the amount of actual energy produced by its oxida- 

 tion within the body, because when muscle burns in oxygen its 

 carbon is converted into carbonic acid, and its hydrogen into 

 water, the nitrogen being to a great extent evolved in the ele- 

 mentary state; whereas when muscle is most completely con- 

 sumed in the body the products are carbonic acid, water, and 

 urea : the whole of the nitrogen passes out of the body as urea, 

 a substance which still retains a considerable amount of potential 

 energy. Dry muscle and pure albumen yield, under these cir- 

 cumstances, almost exactly one-third of their weight of urea; 

 and this fact, together with the above determination of the actual 

 energy developed on the combustion of urea, enables us to de- 

 duce with certainty the amount of actual energy developed by 

 muscle and albumen respectively when consumed in the human 

 body. It is as follows : — ■ 



