RESPrRA TION. 1 39 



freely, taking care not to wound the visceral pleura. 

 The lungs will collapse. Why? 



(21) Replace the manometer, gently blow into the 

 mouthpiece until the lungs have been inflated 

 to their normal size. Measure carefully the rise of 

 mercury in the distal column. 



What degree of positive respiratory pressure will 

 the elasticity of the lungs alone cause. 



(22) What is the significance of the elasticity of the 

 lungs in respiration? 



d. The cardio-pneumatogram. Remove the tube n from 

 the Y-tube, join it to a recording tambour. 



(23) Let a member of the division sit in perfect 

 repose, and while the drum of the kymograph 

 rotates very slowly, hold the mouthpiece between 

 the lips. Hold the nose and suspend all respiratory 

 movements for a period. Let some member of the 

 division count the pulse of the experimenter. 



Trace the cardio-pneumatogram. 



(24) Is there a relation between the rhythm of the 

 pulse and the waves of the tracing ? If so, account 

 for this relation. 



(25) Account for the essential features of the cardio- 

 pneumatogram. 



