12 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 



PREVIOUS RESEARCHES ON THE GASEOUS EXCHANGE 



DURING WALKING. 



Before reporting and discussing the results of our own experiments, a 

 brief abstract is given of all previous research in which the metabolism 

 during walking has been studied. In thus reviewing the work of other 

 investigators, it has seemed advisable to record the results on the basis 

 of the movement of 1 kilogram over 1 meter of level path, i. e., 1 hori- 

 zontal kilogrammeter, and to compare them in a large summary table 

 rather than to give them under each research. This is done in table 



1 (see pages 22 to 27). 



Observations of Smith, 1859. The earliest attempt to measure the 

 gaseous metabolism during walking was made by Edward Smith, who, 

 in his memoirs entitled "Experimental inquiries into the chemical and 

 other phenomena of respiration and their modifications by various 

 physical agencies," 1 gives the details of two walking experiments. In 

 these experiments Smith collected the products of respiration by attach- 

 ing a mask to the face and forcing the expired air through specially 

 constructed boxes, containing caustic potash to absorb the carbon 

 dioxide. The mask had two openings, one for inspired air and the 

 other for expired air, a valve system providing for the separation of the 

 two currents of air. A dry gas-meter was attached at the intake point. 

 The expired air was first passed through a Woulff bottle containing 

 pumice-stone and sulphuric acid, then into a gutta-percha box contain- 

 ing a solution of caustic potash, and finally through a second Woulff 

 bottle containing pumice-stone and sulphuric acid. The walking was 

 done inside of a room and covered a distance of approximately 10 

 meters in each direction. All of the precautions incidental to modern 

 experiments as to recording the barometric temperature and pressure 

 were taken, and a further factor, which is only too frequently neglected 

 in modern work, namely, pulse-rate, was also recorded. The subject 

 carried a spirometer which weighed 7 pounds, but the exact method of 

 transportation is not clear from Smith's description. Both experiments 

 were made in one afternoon, with an intermission of an hour. During 

 the first experiment he walked at the rate of 2 miles an hour and during 

 the second at the rate of 3 miles an hour. For a base-line he deter- 

 mined the metabolism at rest without food and in a sitting position. 



Smith's values, which are given in English grains, were recomputed 

 to grams by Sonden and Tigerstedt. 2 While walking at the rate of 



2 miles an hour, the carbon dioxide per minute was 1.173 grams; at 3 

 miles an hour, 1.674 grams; and sitting at rest without food, 0.482 

 gram. The energy per horizontal kilogrammeter computed from these 

 values is given in table 1, page 22. The results obtained by Smith 

 have been criticized by Gruber 3 and Voit, 4 who both consider them 



'Smith, Phil. Trans. Roy. Soc., London, 1859, 149, p. 681. 

 2 Sonden and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, p. 166. 

 3 Gruber, Zeitschr. f. Biol., 1891, 28, p. 470. 

 4 Voit, Hermann's Haudbuch der Physiologic, 1881, 6, p. 201. 



