TAMBOURS 



235 



connecting the receiving tambour. Across the pan is stretched, not 

 too tightly, a sheet of very light dentist's rubber-dam, which is tied 

 on with thread. Upon the middle of the tambour membrane there 

 rests the foot of the tracing lever. Through this foot every movement 

 of the membrane is communicated to the tracing lever. The tracing 



FIG. 88 



Card. 



Sphyg. 



V 



Pleth. 



Steth. Can. 



Receiving tambours for various purposes. First four for the cardiograph, sphygmograph, digital 

 plethysmograph, and Btethograph, respectively. The last one (Can.) is a thoracic cannula for 

 use in determining intrathoracic pressure. 



lever is delicately pivoted to an arm which extends up by the side 

 of the pan and which is joined to the tube or to the pan, making of 

 the tambour and lever, with its supports, one apparatus. Only the 

 lever holder should be metallic, while long, light straws or reeds with 

 tracing points of parchment or celluloid may be inserted into the 



