214 MAKUAL OF CATTLE-FEEDING. 



cnlar exertion, part of this force is diverted from lliese 

 clianriek, and takes tlie form of nxubcular contraction, 

 while tlie increase in the oxidation of non-nitrogenoub 

 nriatter is a conBeqnence, and not a caxibe, of the work. 



Voit, who believes the albmninoids to be the proximate 

 source of muscular power, advances this argument, and 

 compares the constant decomposition of protein which 

 goes on in the body to the constant flow of water in a 

 stream. A mill situated by the stream may use the whole 

 power of the water, a half, a quarter, or any desired frac- 

 tion, without in the least altering the amount of water 

 running past. So, according to him, the decomposition of 

 protein in the body, which is the source of power to the 

 muscles, goes on constantly, independently of whether the 

 energy which is set free takes the form of motion or ap- 

 pears in some other shape. 



Pettenkofer & Voit (see Chapter VII.) have shown it 

 to be at least -mrj prol)ablc that protein in its decomposi- 

 tion in the body takes up the elements of water and splits 

 up into urea SLXidi fat ; and it has been shown that 100 

 parts of protein might produce in this way 51.4 parts of 

 fat. This process, now, takes place during rest, and the 

 supposition is quite plausible that during work the protein 

 is decomposed completely into carbonic acid, water, and 

 urea, and that thus the latent energy which would other- 

 wise be stored up in the fat is applied to the production of 



It is plain, however, that this argument may be used 

 with equal force to show that the non-nitrogenous matteis 

 of the body may be the source of nuiscular power. 



In trath these considerations simply serve to show that 

 a study of the effects of work cannot give us decisive in- 

 formation as to its souree, both because the production of 



