210 PRINCIPLES OF ANIMAL NUTRITION. 
experience and too well established scientifically to require more 
than illustration. The fact of such an increase was shown in the 
researches of Lavoisier. Scharling,* who as early as 1843 con- 
structed an apparatus somewhat like the Pettenkofer respiration 
apparatus (see p. 70), states in his account of his experiments 
that moderate work increases the excretion of carbon dioxide and 
that it is also greater shortly after a meal. Of other early researches 
upon this point may be mentioned those of Hirn f in 1857, and 
especially those of Smith { in 1859. The investigations of Petten- 
kofer & Voit § in 1866 appear to have been the first to be executed. 
in accordance with modern methods. Their results have already 
been cited in their bearing upon the influence of work on proteid 
metabolism, but may be repeated here: 
— Water Excreted. 6 
Nitrogen | Dioxide |————|_ Taken | Number 
Grms. ’ | Excreted, Tn Evapo- Up, of, Expert 
Grms. Urine. rated, Grms. saa 
Grms. Grms. 
Fasting: : 
Rest. cocsavwas 12.4 716 1006 821 762 2 
Work ......... 12.3 1187 746 1777 1072 1 
Average diet: 
Rest. zie ssi 17.0 928 1218 931 832 3 
Work ......... 17.3 1209 1155 1727 981 2 
Subsequent investigators such as Speck, || Hanriot & Richet,{ 
Katzenstein,** Loewy,{+ and many others have fully confirmed the 
results of the early experimenters. The increase in the oxygen 
taken up was not actually demonstrated in all of these experiments, 
but it was in some and may be reasonably inferred in the remainder. 
* Ann Chem Pharm, 46, 214 
t Comptes rend Soc. de Physique de Colmar, 1857; Revue Scientifique, 
ler Semestre, 1887. 
} Phil. Trans., 1859, p 681. 
§ Zeit f Biol., 2, 478. 
| Schriften der Gesell.der ges. Naturwiss zu Marburg, 1871; Arch. klin 
Med., 45, 461, 
{| Comptes rend., 104, 435 and 1865; 105, 76; Ann. de Chim. et de Phys., 
(6), 22, 485. 
** Arch ges Physiol., 49, 330. 
Tt Ibid., 49, 405. 
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