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JOHN R. MURLIN 



from C into C', thereby aspirating the air into C and returning air from 

 C' to the respiration chamber. By thus absorbing the CO 2 produced by 

 the subject the volume of the contained air is reduced and its place is 

 taken by oxygen driven from the flask N by water pressure. The experi- 

 ment is continued until all the oxygen contained in the three flasks is used 

 up. The last 300 or 400 c.c. of oxygen is driven over under pressure and 

 the experiment is continued until the atmospheric pressure is again 

 reached. At this moment samples of the chamber air are drawn off for 

 analysis. 



The CO 2 is discharged from the KOH by weak sulphuric acid and is 

 again caught in a KOH absorber to be weighed. It could not be obtained 



> i 



Fig. 4. Respiration apparatus of Regnault and Reiset. A, chamber for animal; 

 B, water jacket; C, carbon dioxid absorbers; a, b, c, manometer for recording pressure 

 inside respiration chamber; 2V, 2V', N", flasks containing oxygen; T, T', thermometers. 



by direct weighing of the absorbers because they contain some water ex- 

 haled from the animal as well as CO 2 . To the amount of CO 2 contained 

 in the KOH is added the residual amount found in the chamber air by 

 analysis at the end of the observation. 



The oxygen absorbed is found by measurement of the contents of the 

 flasks corrected by analysis of the chamber air. 



b. The Apparatus of Hoppe-Seyler(c). Similar in principle to that 

 of the original construction of Regnault and Reiset this apparatus con- 

 sists of a horizontal cylinder two meters in length, 1.66 meters in diameter 

 and a total capacity of 4.480 cubic meters. It is, therefore, large enough 

 for observation on the human subject. 



The respiration chamber rests on the ground floor of the laboratory, 



