364 



THE RESPIRATION 





Fig. 131. — Curves showing variations in alveolar gas tensions after forced breathing for two 

 minutes. Thin line = O* tension; thick line = COo tension. Double line = normal alveolar 

 C0 2 tension. Dotted line shows the alveolar COa tension at which breathing would recommence 

 at the end of apnea with the alveolar 2 pressures shown by the thin line. The actual breathing 

 is indicated at the lower part of the figure. It is periodic to start with. (From Douglas and 

 Haldane.) 



