APPLIED PHYSIOLOGY 



able to abolish the apnoeic period by causing a patient 

 exhibiting Cheyne- Stokes respiration to inhale carbonic 

 acid. 



Ehythmical respiration is often accompanied by similar 

 periodic variations in the control exercised over the blood- 

 vessels by the general vasomotor centre and over the 

 pupil by the pupil centre, and even by rhythmical 

 increase and diminution of the activity of the brain 

 cortex as manifested in consciousness. 



It is noteworthy that in sleep, when the higher centres 

 are presumably less active, the respirations readily take 

 on a rhythmical character, particularly in childhood, 

 when the control of the lower centres is presumably not 

 well developed. 



