RESPIRATION 



91 



For the following experiments the slowest rate of drum is to be used, and 

 the subject must not be allowed to see the tracing which is being taken. 



Record of respiratory movements. Apply a stethograph (Marey's 

 or Sanderson's) (fig. 71) to the chest, and register the movements of 

 respiration by means of a recording tambour. 



m 



FIG. 75. SPIBOMETEE ARRANGED TO REGISTER, UPON A SLOWLY REVOLVING DRUM. THE AMOUNT 

 OF AIR RESPIRED, sp., BODY OP SPIROMETER ; cy, MEASURING CYLINDER WITH SCALE AND 

 WRITER ATTACHED ; v., v'., WATER VALVES ; m, MOUTHPIECE. 



Apno3a. Remove the lever of the recording tambour from contact 

 with the drum. Cause the subject to take a number of deep respira- 

 tions at a rapid rate. Then let him cease these voluntary efforts, and 

 take a record of the ordinary breathing which succeeds to them. 

 There will probably be a pause (apnoea) followed by respirations which 

 are at first shallow but gradually become of the ordinary character. 



Measurement of amount of air passing into and out of lungs. 

 Using either an airtight mask or a niouth-tube (in this case the nostrils 



