186 PRACTICAL PHYSIOLOGY 



Olein : C 3 H 5 (C 18 H 33 2 ) 3 + 800 2 = 57C0 2 + 52H 2 0. 



^C0 2 _57 

 ~OT~80~ 



The effect of muscular exercise upon the respiratory exchange is 

 most marked ; hard work may increase it three or four times. 



For exact work upon the respiratory exchange of man a respiration 

 chamber is required. Few laboratories possess such an expensive 

 apparatus, but the principles can be studied in the simple form of 

 respiration apparatus for mice. 



CHAPTER XLVIII. 

 RESPIRATION APPARATUS. 



The Haldane-Pembrey Respiration Apparatus for the Mouse. The 

 apparatus is constructed as in Fig. 183. Each double absorption tube 

 is fitted with a wire loop, so that the glass need not be touched with 

 the hand. The animal chamber- a light beaker is provided with a 

 thermometer and is also fitted with a wire loop. The moisture given 

 off by the animal is absorbed by pumice saturated with sulphuric acid 

 in the tubes AB. The carbon dioxide is removed by soda lime in the 

 tube C, and the water given off by the soda lime is caught by the sul 

 phuric acid tube D. 



M N A B c D 



FIG. 183. The Haldaiie-Pembrey respiration apparatus for the mouse. 



The animal is weighed in the beaker (with the tubes closed) before 

 and after the experiment. A dummy beaker is placed in the opposite 

 scale pan. The tubes AB and CD are also weighed against a dummy 

 pair of tubes. During the weighings the exit and entrance tubes are 

 left unstoppered. By these means errors due to condensation of 

 moisture and changes of barometric pressure or temperature are 

 avoided, and the weighings can be carried out to less than a milli- 

 gramme. 



The air entering the chamber is freed from carbon dioxide and water 



