PREVIOUS RESEARCHES ON GASEOUS EXCHANGE. 15 



out a number of observations in Zuntz's laboratory in Berlin, using the 

 treadmill. 1 A dry gas-meter weighing 7 kilograms was employed and 

 was carried by the subject. In most of the experiments the inspired 

 and expired air were separated by a valve system and a mouthpiece and 

 nose-clamp were used. It is interesting to note that in the severe work 

 of going uphill in this series of experiments, the authors record that the 

 breathing appliances were very uncomfortable, particularly the nose- 

 clip. They accordingly trained themselves to inspire through the nose 

 and expire through the mouth, a procedure which they satisfied them- 

 selves gave accurate results. To establish a base-line, numerous exper- 

 iments were made with the subject in a sitting position, these being 

 carried out in the laboratory in Berlin, in the hotel at Zermatt, and also 

 in the camp and on the glacier in the mountains. Three walking 

 experiments were made with Zuntz as subject in a room of the labora- 

 tory building and two on the treadmill, which was in a practically hori- 

 zontal position. Two treadmill experiments were also made with 

 Schumburg as a subject. The energy per horizontal kilogrammeter, as 

 computed from the difference between the sitting values and the walk- 

 ing values, is given in table 1, page 22. 



Observations of A. Loewy, J. Loewy, and L. Zuntz, 1897. In connec- 

 tion with their studies in the Alps, A. Loewy, J. Loewy, and L. Zuntz 

 made several experiments in Berlin on the treadmill in the Landwirt- 

 schaftliche Hochschule. 2 Two experiments were made with A. Loewy, 

 three with J. Loewy, and five with L. Zuntz. A 6.6 kilogram dry gas- 

 meter was carried by the subject on his back and connected with the 

 Lob valve attached to the mouthpiece. The nose was closed with a 

 clamp. For the experiments made with A. Loewy, a base-line was used 

 which was founded upon earlier observations. The resting values for 

 J. Loewy and L. Zuntz were determined presumably with the subject 

 sitting. No statement is made as to whether the subjects were in a 

 post-absorptive condition or not. Certain experiments were also made 

 at Col d'Olen, in which the subject likewise carried the dry gas-meter, 

 but for these experiments the resting values were obtained with the 

 subject in a lying position. The results for the observations with the 

 subject walking on a level are summarized in table 1, page 22. 



Observations of L. Zuntz, 1899. In his observations regarding the 

 gaseous-exchange of bicycle-riders, Leo Zuntz included a number of 

 experiments made on the treadmill in the Landwirtschaftliche Hoch- 

 schule. 3 The statement is made that the treadmill had an inclination 

 of approximately 1 degree. Of special interest in these observations 

 is the fact that Leo Zuntz paid particular attention to the influence of 

 speed upon the gaseous metabolism, varying the rate of walking from 



J Schumburg and Zuntz, Archiv f. d. ges. Physiol., 1896, 63, p. 461. 

 2 A. Loewy, J. Loewy, and L. Zuntz, Archiv f. d. ges. Physiol., 1897, 66, p. 477. 

 3 L. Zuntz, Untersuchungen iiber den Gaswechsel und Energieumsatz des Rad ahresHirsch- 

 wald, Berlin, 1899. 



