INFLUENCE OF MUSCULAR EXERTION UPON METABOLISM. 187 
RESPIRATORY QuOTIENT.—By analogy with investigations upon 
respiration we may designate the ratio between the oxygen con- 
sumed and the carbon dioxide given off by the muscle as the respi- 
ratory quotient of the muscle. Numerous investigations upon this 
point have shown that during contraction much more carbon diox- 
ide is given off than corresponds to the oxygen consumed, or, in 
other words, the respiratory quotient of the active muscle is con- 
siderably greater than unity. : 
As early as 1862 Sczelkow * determined the gaseous exchange 
between the blood and the muscles of the posterior extremities of 
. a dog, tetanus being produced by an electric current. He found 
that during rest more oxygen disappeared from the blood than 
corresponded to the carbon dioxide taken up by it, while during 
tetanus, on the contrary, the carbon dioxide considerably exceeded 
the oxygen. His results, calculated for the posterior extremities 
alone, were as follows: 
Per Minute. 
. Respiratory 
Experiment. Carbon Oxygen Quotient. 
Dioxide c.c. 
c.c. 
ie See ey nto eee , 1.60 4.10 0.41 
Leveson ee ee ee 10.37 3.92 2.65 
ORES saan vem aeewest 2.62 4.25 0.62 
Zeveeeeees | Tetanus ..............2000. 12.38 | 10.52 1.18 
RESt: ho ds Bo tcne ge De oes 1.73 3.21 0.54 
Bese qa seas | Tei ANUS dana ius ox aa ease 2 10.62 7.55 1.41 
Dea vic meds cecal nai lea ataee 3.53 4.71 0.75 
Ai ainesias | Tetanus -........ssss0sseee 12.19 | 9.38: | 1.30 
Pe ois hat Fanieemanesee: 2.33 5.82 0.40 
Beeeeeeees { TRANS sccbiusauvacosaen 12.95 | 18.71 0.80 
In the above experiments, with a single exception, the quantity 
of oxygen consumed by the active muscles was more than that 
taken up in a state of rest, but the increase in the amount of carbon 
dioxide given off was still greater, so that the respiratory quotient 
was largely increased, exceeding unity in every instance but one. 
* Sitzungsber. Wiener Akad. d. Wiss., Math-Naturwiss. Klasse, 45, IT, 171. 
