204 MANUAL OF CzMTLK-FKEDIXG^ 



J 1. EFrECTS OF MUSCULAB EXEETION ON EXCEETION. 



Voit's Experiments, — It was formerly the common 

 belief that continued activity of the muscles caused a wear- 

 ing out of those organs, and, as a consequence, largely in- 

 creased the protein consumption and the excretion of 

 nitrogen. This belief, however, was never founded on 

 experimental evidence, and has now been rendered un- 

 tenable in its original form. 



Karl Voit, of Munich, was the first to make exact ex- 

 periments on the subject, and in 1860 he published the 

 results of his' researches,"^ which showed that, contrary to 

 the then generally accepted theory, muscular exertion did 

 not inciease the amoimt of protein decomposed in the body. 



His experiments were made on a dog weighing about 

 83 kilogrammes (70 lbs.). The work which he performed 

 on the woi king-days (by running in a treadmill) was very 

 considerable, being estimated at l.Y kilogramme-metres f 

 per second for the whole twenty-four hours (the work 

 being actually performed in six periods of ton minutes 

 each), while the work performed by a man working eight 

 hours in the twenty-four is estimated at only 2.3 kilo- 

 gramme-metres per second for the twenty-four hours. In 

 some of the experiments the animal received no food ; in 

 others he was given a daily ration of 1,500 grammes of 

 fat-free meat, with which amount the body was allowed to 

 come into equilibrium l)efore the beginning of the experi- 

 ment. The diet on the resting and working-days was al- 

 ways the same, except that the animal was allowed to 

 drink all the water he desired. Each experiment extended 



* " XJi^tersnchangen uber den Binfluss des Koclisalzea, des Kaffee's 

 und der Muskelbewegungcn auf den Stoffwechsel," 18G0. 



f A kilogrammo-metre is the amounfc of force required to raise one 

 kilogramme tlxrough a space of one metre, in opposition to gravity. 



