LABORATORY MANUAL OF PHYSIOLOGY. 



cording tambour, whose writing lever is applied to the smoked sur- 

 face of a medium-slow drum. The increase in pressure at each 

 stroke of the pump is partly employed in distending the vessel. 

 This causes a bulging of the vessel and a hardening which can be 

 felt by the finger and which in this case is transmitted through the 

 receiving tambour to the recording tambour and is written as a 

 curve on the revolving drum. This is the pressure pulse and is 

 indicative of the rise in pressure in the artery with each systole of 

 the ventricle. The lever of the recording tambour should be deli- 

 cately adjusted to the surface of the drum so as to reduce friction 

 to a minimum. 



What is the form of the pressure pulse in this instance? How 

 does the systolic rise compare with the diastolic fall? Are there 

 any secondary waves ? If so, what is their significance ? 



Increase the rate of the pump stroke. What change occurs in 

 the pulse wave? Decrease the rate of the pump stroke. What 

 change occurs in the form of the pulse wave ? 



Increase the peripheral resistance by tightening the clamps on 

 the capillaries. What is the effect on the pulse? Decrease the 

 peripheral resistance. What is the effect on the pulse ? 



With the capillary clamps so applied that the venous outflow is 

 continuous, place the finger upon the venous tube while the heart 

 bulb is rhythmically pressed. Is any pulse felt in the veins ? Ap- 

 ply the receiving tambour to the vein. Is any pulse recorded by 

 the recording tambour ? 



Release the compression in the capillary region until the venous 

 outflow becomes remittent. Is a pulse tracing now obtainable from 

 the veins ? Explain. 



^kx. PULSE RECORD IN MAN. 



By the Tambour Method. A simple method for recording the 

 pulse is by some such scheme as depicted in Fig. 34. This con- 

 sists of a thistle tube, T, to act as a receiving tambour, and a re- 

 cording tambour, R, connected with the receiving tambour by 

 strong-pressure tubing for transmitting the impulse from one tarn- 



[106] 



