Cakbon-Dioxide Elimination. 155 



From over 80 experiments on himself, Speck collected a number that he con- 

 sidered truly representative of his normal metabolism in the morning without 

 food, and from these results he concluded that on the average he excreted 234 

 c. c. of carbon dioxide per minute. 



Using the Pettenkofer respiration apparatus in Munich, Moller * made experi- 

 ments with a number of hospital patients and 3 healthy individuals. Of these, a 

 man, 44 years of age, weighing 68.8 kilos, exhaled 33.5 grams of carbon dioxide 

 per hour, or 284 c. c. per minute and 4.14 c. c. per kilogram per minute. An- 

 other subject, 36 years of age, weighing 52.5 kilos, exhaled 33 grams per hour, 

 or 280 c. c. per minute and 5.32 c. c. per kilogram per minute. A third subject, 

 28 years of age, with a body- weight of 70 kilos, gave off 44.3 grams of carbon 

 dioxide per hour, or 376 c. c. of carbon dioxide per minute and 5.38 c. c. per 

 kilogram per minute. 



In 1888 2 there appeared a description of a new method for studying the 

 respiratory exchange which was destined to revolutionize the study of metab- 

 olism during short periods the method of Zuntz-Geppert which has, in the 

 hands of Magnus-Levy, Loewy, and many others of the Zuntz school, yielded 

 a large number of results. The subject breathes through a mouthpiece into a 

 carefully calibrated gas-meter, and an aliquot portion of the air is taken for 

 analysis in duplicate by exact methods. It is impossible in this abstract to 

 include all the results obtained by the many workers with this method. Those 

 most comparable with the results here reported are such as were obtained on 

 men lying quietly, 12 hours after the last meal. The method has been used 

 extensively for studying the influence of various factors upon the respiratory 

 exchange and almost invariably each research has included a certain number 

 of experiments on the resting value without food, as a basis for comparison in 

 studying the different factors. It is still a matter of conjecture as to how 

 accurate are the results with this method when the subjects are not trained 

 in the peculiar respiration necessitated by using the rubber mouthpiece and 

 nose-clamp. In all probability the results obtained by Zuntz and his co-workers 

 on themselves have a high degree of accuracy. The results obtained on others 

 are open to reasonable criticism. Fortunately, most of the work, and that most 

 carefully carried out, was done on the subjects trained in the Zuntz school. 

 Magnus-Levy 3 used the method especially for studying the influence of the 

 ingestion of food upon the respiratory exchange. 



The most recent collection of the results obtained by this important method 

 is given by Loewy. 4 The results, not only for the carbon-dioxide exhalation but 

 likewise for the oxygen consumption and the respiratory quotient, are given in 

 table 64, which is copied directly from Loewy's article. The larger number of 



1 Moller, Zeitschr. f. Biol, 1878, 14, p. 542. 



2 Zuntz and Geppert, Archiv f. d. ges. Physiol., 1888, 42, p. 196. 

 : Magnus-Levy, Archiv f. d. ges. Physiol., 1894, 55, p. 1. 



4 Loewy, Oppenheimer's Handbuch der Biochemie des Menschen und der Tiere, 

 Jena, 1908, 4, p. 179. 



