QUANTITATIVE ESTIMATION OF THE RESPIllED GASES. 



251 



The apparatus of Andral and Gavarret is thus used : The operator breathed 

 several times into a capacious cylinder (Fig. 110). A mouth-piece (M) was placed 

 air-tight over the mouth while the nostrils were closed. The direction of the 

 respiratory current was regulated by two so-called " Miiller's valves " (mercurial), 

 (a and 6). With every inspiration the bottle or valve, a (filled below with Hg. and 

 hermetically closed above) permits the air inspired to pass to the lungs during 

 every expiration, the expired air can pass only through 6 to the collecting cylinder C 



2. If the gases given off by the ekin are to be collected, a limb, or whatever part 



Fig. 110. 



I. Apparatus of Andral and Gavarret for collecting the, expired air C, large 

 cylinder to collect the air expired; P, weight to balance cylinder; a, 6, two 

 Muller's valves ; M, mouth-piece. II. Anthracometer of Vierordt. 



Fig. 111. 



Respiratory Apparatus of Scharling d, bulb containing caustic potash to absorb 

 C0 2 from in-going air; A, box for man or animal experimented on; e and g, 

 tubes containing sulphuric acid to absorb watery vapour; /, potash bulb to 

 absorb C0 2 given off; C, vessel filled with water to aspirate air through the 

 foregoing system; h, stop-cock. 



