820 CHEMISTRY OF RESPIRATION. 



method. The large respiration apparatus of iSoxDEN and TTGERSTEDT as well a.s 

 of ATWATER and ROSA * are based upon this principle. 



SPECK'S Method. 2 For briefer experiments on man SPECK used the follow- 

 ing: He breathes through a mouthpiece with two valves, closing the nose with a 

 clamp, into two spirometer-receivers, where the gas-volume can be read off very 

 accurately. The air from one of the spirometers is inhaled through one valve 

 and the expired air passes through the other into the other spirometer. By means 

 of a rubber tube connected with the expiration-tube an accurately measured part 

 of the expired air may be passed into an absorption-tube and analyzed. 



ZUNTZ and GEPPERT s Method* This method, which has been improved by 

 ZUNTZ and his pupils from time to time, consists in the following: The individual 

 being experimented upon inspires pure atmospheric air through a very wide feed- 

 pipe leading from the open air, the inspired and the expired air being separated by 

 two valves (human subjects breathe with closed nose by means of a soft-rubber 

 mouthpiece, animals through an air-tight tracheal canula). The volume of the 

 expired air is measured by a gas-meter and an aliquot part of this air collected and 

 the quantity of carbon dioxide and oxygen determined. As the composition of the 

 atmospheric air can be considered as constant within a certain limit, the production 

 of carbon dioxide as well as the consumption of oxygen may be readily calculated 

 (see the works of ZUNTZ and his pupils) . 



HANRIOT and RICHET'S Method 4 is characterized by its simplicity. These 

 investigators allow the total air to pass through three gasometers, one after the 

 other. The first measures the inspired air, whose composition is known. The 

 second gasometer measures the expired air, and the third the quantity of the 

 expired air after the carbon dioxide has been removed by a suitable apparatus. 

 The quantity of carbon dioxide produced and the oxygen consumed can be readily 

 calculated from these data. 



APPENDIX 



THE LUNGS AND THEIR EXPECTORATIONS. 



Besides proteins and the albuminoids of the connective-substance 

 group, lecithin, taurine (especially in ox-lungs), uric acid, and inosite 

 have been found in the lungs. POULET 5 claims to have found a special 

 acid in the lung-tissue, which he has called pulmotartaric acid. Glyco- 

 gen occurs abundantly in the embryonic lung, but is absent in the adult 

 organ. The proteolytic enzymes also belong to the physiological con- 

 stituents of the lungs. They are active in the autolysis of the lungs 

 (JACOBY) as well as in the solution of pneumonic infiltrations (FR. 



MlJLLER 6 ). 



The lungs have a strong reducing property, which BOHR explains by 

 the extensive oxidation processes in the lungs. According to N. SIEBER 



1 Pettenkofer's method; see Zuntz, 1. c.; Sonde"n and Tigerstedt, Skand. Arch. f. 

 Physiol., 6; Atwater and Rosa, Bull, of Dept. of Agriculture, 63. Washington. 



2 Speck, Physiologie des menschlichen Atmens. Leipzig, 1892. 



3 Pfliiger's Arch., 42. See also Magnus-Levy in Pfliiger's Arch., 55, 10, in which the 

 work of Zuntz and his pupils is cited. 



4 Compt. rend., 104. 



5 Cited from Maly's Jahresber., 18, 248. 



6 Jacoby, Zeitschr. f. physiol. Chem., 33; Miiller, Verhandl. d. Kongress. f. inn. 

 Medizin, 1902. 



