RESPIRATION. 115 



(1) During one revolution of the drum 5 minutes 

 note the rate and rhythm of the respiratory move- 

 ments as recorded by the stethograph, and chrono- 

 graph. 



(2) Does the stethogram show anything more than 

 rate and rhythm ? 



(3) What phase of a respiratory cycle does a rise of 

 the lever indicate ? 



(4) What is the relative duration of inspiration and 

 expiration as indicated by the stethogram? 



(5) Does the stethogram indicate any variation indif- 

 ferent parts of the inspiratory act ? Of the expira- 

 tory act? 



(6) Differentiate the essential from the nonessential 

 in the stethogram and determine as far as may be, 

 the cause of each. 



Intra-thoracic pressure. 



Trace upon the drum a stethogram and chronogram 

 as well as an intra-thoracic pressure record, taking 

 care that the tracing points of the recording tam- 

 bours are in a vertical line. 



(7) Does the rhythm of varying pressure correspond 

 to the rhythm of the respiratory movements ? 



(8) If so, does that necessarily establish between them 

 the relation of cause and effect? 



(9) What change of pressure is indicated by the rise 

 of the pressure lever? 



(10) What movement of the pressure lever corre- 

 sponds to a rise of the stethograph lever? 



(11) What is the condition of intra-thoracic pressure 

 during inspiration ? During expiration ? 



(12) Stop the entrance of air into the respiratory pas- 

 sages by closing the rabbit's nostrils. What effect 

 does this have upon the respiratory movements? 



