CARBOHYDRATES. 69 



ment of Fick and Wislicenus. 1 These scientists attempted to find out 

 what substances were chiefly decomposed as a result of strenuous mus- 

 cular work. At that time Liebig's 2 theory prevailed that the muscles 

 performed work at the cost of albuminous substances, and they decided 

 to test this experimentally. If Liebig's theory were correct, it was to be 

 expected that the elimination of nitrogen would be increased as a result 

 of muscular activity. Fick and Wislicenus climbed Mount Faulhorn, 1956 

 meters above the Lake of Brienz, which was the starting-point. For sev- 

 enteen hours before the start, during the ascent (which required six hours), 

 and for six hours following, care was taken to eat only food which was free 

 from nitrogen. All the urine passed during the ascent and the six hours 

 following was carefully collected and the nitrogen accurately determined. 

 From the results obtained by chemical analysis it was found that Fick had 

 decomposed 38.3 grams of albumin, and Wislicenus 37 grams. These 

 amounts of albumin correspond to about 250 heat units in each case, or 

 106,000 kilograms of work. If we estimate the actual work performed in 

 climbing the mountain we arrive at the following values. Wislicenus 

 weighed 76 kilograms. By simply raising this weight to the height of the 

 mountain peak, 76 X 1956 = 148,656 kilograms of work was performed. 

 These values suffice to show that the work could not have been at the ex- 

 pense of albumin alone. This fact is still more striking when we remember 

 that the above value of albumin in heat units is too high, for it is based 

 upon the assumption that the carbon is completely changed to CO2 and the 

 hydrogen to H 2 0. Now, as a matter of fact, nowhere near this amount of 

 energy is obtained by the consumption of albumin in the animal organism, 

 for a part of the carbon, some of the hydrogen, and the greater part of the 

 nitrogen, are eliminated in the form of urea. In man, the amount of urea 

 formed is as a rule equal to one-third the weight of albumin decomposed. 

 Therefore from the above heat value of albumin we must deduct one-third 

 the heat of combustion of the same weight of urea. On the other hand, 

 as a matter of fact, the scientists performed much more work than we 

 have estimated. Fick and Wislicenus estimate the amount of work per- 

 formed by their circulatory and respiratory apparatus as 30,000 kilogram- 

 meters. Furthermore, it must be taken into consideration that in every 

 motion, in every step, work is performed which is transformed into heat 

 and lost as far as the work performed is concerned. According to Helm- 

 holtz, only one-fifth of the actual heat of combustion is transformed into 

 external work. It is perfectly certain, therefore, that we can safely con- 

 clude from the above experiment that albumin alone is not the source of 

 muscular work, but, on the other hand, we are not justified in concluding 



1 Vierteljahresschrift des Ziiricher naturforschenden Gesellsch. 10, 317 (1865). 



2 Chemische Briefe (1857). Cf. also Ann. 153 1, and 157 (1870); C. Voit: Z. Biol. 6, 

 305(1870); Schenck: Arch, exper. Path. Pharm. 2, 21 (1874). 



