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A TEXTBOOK OF PHYSIOLOGY 



if the ascent has been fairly rapid by railway, so that no adapta- 

 tion takes place during the journey. It is suggested that the oxygen- 

 want leads the kidney to excrete more base than acid from the blood, 

 and thus increasing the breathing, lessens the concentration of carbon 

 dioxide in the blood and alveolar air. By lessening the concentration 

 of C0 2 in the alveolar air, that of oxygen is increased. 



The effect of oxygen-want is well seen in the inability voluntarily 

 to hold the breath for any length of time (Fig. 172). Acclimatization 

 takes place in about eight to ten days. This is due, in the first 



FIG. 174. VIEW OF CHAMBER USED FOR STUDY OF EFFECTS OF COMPRESSION 

 DECOMPRESSION ON MAN : WORKMAN INSIDE. (Hill and Greenwood.) 



The chamber is fitted with electric belt, electric light, telephone, observation window, 

 compression pipe from gas-engine, decompression tap. 



place, to a concentration of the blood-plasma, followed by an increased 

 formation of blood-corpuscles and haemoglobin (Fig. 18). Hence 

 the oxygen-carrying power of the blood is increased ; an alteration in 

 the acid concentration of the plasma compensates for the diminished 

 partial pressure of carbon dioxide. 



On the strength of determinations of the partial pressure of 

 oxygen in the blood, by the CO method (p. 273), it is asserted 

 that compensation is brought about by secretory activity of the lung 

 epithelium, since the oxygen-pressure of the arterial blood has been 



