x CONTENTS 



Exact physiological regulation of the blood-gases. 



Evidence that C0 2 acts physiologically as an acid. 



Investigations of the reaction of blood. 



Extreme delicacy of the physiological regulation of 

 the blood reaction. 



Regulation of the blood-reaction by the lungs, liver, 

 and kidneys. 



Effects of want of oxygen on the breathing. 



High balloon ascents, CO poisoning, and mountain 

 sickness. 



Acclimatisation to oxygen want: — the Anglo-Ameri- 

 can Expedition to Pike's Peak in 1911. 



Acclimatisation effects of oxygen want on the 

 breathing. 



Acclimatisation effects on the haemoglobin percent- 

 age and blood-volume. 



Acclimatisation effects on active secretion inwards of 

 oxygen by the lungs. 



Factors in acclimatisation to want of oxygen. 



III. Regulation of the Environment, Inter- 

 nal and External 61 



Further analysis of oxygen secretion by the lungs. 



Secretion of oxygen by the swim-bladder. 



Secretion in other glands. 



Analogy between secretion and cell-nutrition. 



The circulatory regulation of carriage of oxygen 

 and C0 2 . 



Regulation by vaso-motor nervous control. 



Evidence that this control depends upon the metabo- 

 lism of the tissues. 



Evidence that the heart's action in pumping blood 

 depends on the same conditions. 

 ^ Part played by contraction of the veins. 



The blood as a constant internal environment. 



Regulation of this internal environment by the kid- 

 neys. 



