RESPIRATION 333 



diffuses outwards from the blood much more readily than oxygen 

 diffuses inwards (see Chapter VIII). The deficiency of CO2 in 

 the arterial blood would prevent or minimize the true hyperpnoea, 

 .md lessen the increase of circulation through the tissue capillaries 

 and the pressor excitation of the vasomotor center. But it would 

 increase the true tissue anoxaemia with a given degree of cyanosis. 

 Anoxaemia in the coronary circulation would also lead to the 

 enfeebled action of the heart, as shown by the very weak and 

 feeble pulse. The symptoms generally were those of a pure anox- 

 aemia with urgent danger of failure of the respiratory center in 

 ;he manner already referred to in Chapter VI. 



In these cases bleeding was of course useless. On the other 

 land injection into the blood of saline solution or, still better, 

 7um-saline, seemed likely to be of some use in view of the failing 

 )lood pressure. By far the most effective treatment, however, was 

 :he continuous administration of air enriched with oxygen, par- 

 icularly if this was begun early and before there was time for the 

 langerous effects which continued severe anoxaemia causes. By 

 his means the oxygen pressure in the alveolar air was sufficiently 

 •aised to permit of a nearly normal aeration of the arterial blood; 

 md the administration could be continued till the lung inflamma- 

 ion subsided. 



The chronic after effects on the respiratory center of irritant 

 jases have already been referred to in former chapters. 



