16 MUSCULAR WORK 
INVESTIGATIONS BY ZUNTZ AND HIS ASSOCIATES. 
The first extensive investigation on the effect of muscular work upon 
metabolism carried out by means of the Zuntz-Geppert apparatus was that 
reported by Katzenstein. The work consisted of moving a Gaertner ergostat 
with the arm, and walking on a level and also on an inclined plane by means of 
a treadmill designed by Lehmann and Zuntz. The experiments were for the 
most part of very short duration — only 4 to 6 minutes. Katzenstein found 
no material alteration in the respiratory quotient, notwithstanding the 
increased metabolism. He also made a series of observations on the after- 
effect of work upon metabolism. 
In 1898 Leo Zuntz b published a description of a series of experi- 
ments made with a Zuntz apparatus for studying the metabolism during 
bicycle riding. The work performed was sufficient to produce 9 times the 
amount of carbon dioxide excreted during rest. This series of experiments 
represents the first careful attempt to study the metabolism during bicycle 
riding. 
The effect of different diets upon muscular work was studied in a long 
series of experiments, 176 in number, by Frentzel and Reach. The work was 
performed on a treadmill in the Zuntz laboratory . d Inasmuch as this is the 
first time that an extensive investigation was made on the effect of muscular 
work upon the character of the katabolism, we shall have occasion to refer 
to it frequently on subsequent pages. 
In 1901 Heinemann * reported a series of experiments performed in 
Zuntz's laboratory, in which the Gaertner ergostat and the Zuntz-Geppert 
apparatus were likewise used. In these experiments special attention was 
also given to the effect of different diets upon the amount of muscular work, 
and upon the quantity and quality of the material burned during muscular 
activity. The muscular work, which was approximately constant in all the 
experiments, averaged 360 kilogrammeters per minute. 
A practical application of the study of muscular work as influencing the 
metabolism was made by Reach in the laboratory of Durig in Vienna/ 
Reach used for the muscular work the turning of a centrifugal milk-separator 
which had been carefully calibrated by an electrically-driven motor. The 
gaseous metabolism was determined by the Zuntz-Geppert apparatus and 
compared with the amount of external muscular work performed. From 
his results he then computed the calories per kilogrammeter in turning the 
wheel of the machine, and compared his results with similar body-activity 
observed by Katzenstein, Sonden and Tigerstedt, Johansson and Koraen, 
and Hanriot and Richet. 
In connection with their study of the fasting metabolism of a subject 
(Breithaupt) who fasted 6 days, Lehmann and Zuntz ° made observations on 
the effect of muscular work, using the Gaertner ergostat and collecting the 
gas samples in short periods, namely, from 2 to 5 minutes. Their observa- 
tions also included data with regard to the after-effects of work. 
o Katzenstein, Pfluger's Arohiv f. d. ges. Physiol., 1891, 49, p. 330. 
» Leo Zuntz, Pfluger's Archiv f. d. ges. Physiol., 1898, 70, p. 346. 
e Frentzel and Reach, Pfluger's Archiv f. d. ges. Physiol., 1901, 83, p. 477. 
<* The treadmill used is described in the Landw. Jahrb., 1889, 28, p. 7. 
« Heinemann, Pfluger's Archiv f. d. ges. Physiol., 1901, 83, p. 441. 
/ Reach, Landw. Jahrb., 1908, 37, p. 1053. See also Biochem. Zeitschr., 1908, 14, p. 430. 
Lehmann and Zuntz, Archiv f. path. Anat. u. Physiol., 1893, 131, supp., p. 92. 
