GASES OF THE BLOOD. 



34. Extraction of the Blood Gases. 



The extraction of the gases from the blood, and their collection for chemical 

 analysis, are carried out by means of the mercurial pump (C. Ludwig). Fig. 15 

 shows in a diagrammatic form the arrangement of Pnuger's gas-pump. 



It consists of a RECEPTACLE FOR THE BLOOD, or "BLOOD-BULB" (A), a glass- 

 globe capable of containing 250 to 300 c.c.m., connected above and below with 

 tubes, each of which is provided with a stop-cock, and b ; b is an ordinary stop- 

 cock, while a has through its long axis a perforation which opens at z, and is 

 so arranged that, according to the position of the handle, it leads up into the 



Fig. 15. 



Scheme of Pfkiger's gas-pump A, blood-bulb ; a, stop-cock, with a longitudinal 

 perforation opening upwards ; a', the same opening downwards ; b and c, 

 stop-cocks ; B, froth-chamber ; d, e, f, stop-cocks ; G, drying-chambers, 

 containing sulphuric acid and pumice-stone ; D, tube, with manometer, y. 



