53 



(4) Place the finger on the radial artery of a companion 

 and study the pulse as to (a) rate, (b) rhythm, (c) force, (d) size, 

 (e) form of wave. 



(5) Does the wave develop simultaneously throughout the 

 arterial system or does it pass out to the periphery ? Place 

 one finger over the carotid and another over the radial artery 

 and time the appearance of the wave under each. 



(6) Using Dudgeon's or Marey's sphygmograph, under the 

 direction of the demonstrator, take a tracing of the radial 

 pulse. 1. Feel the radial pulse (note its rate). 2. Mark the 

 artery with an aniline pencil. 3. See that the pad on the 

 spring of the sphygmograph is over the artery. 4. Strap the 

 instrument on, varying the tightness of the band to give the 

 best range of movement. 5. Vary the tension of the spring 

 by means of the eccentric till the largest range of movement 

 of the lever is secured. 6. Slip the smoked papers under the 

 wheels and under the point of the lever, using a pin to raise 

 the point of the latter if necessary. 7. Now start the clockwork 

 and run off a tracing. 8. Mark upon it the name and age of 

 the subject, the date and the rate of the heart per minute, and 

 fix it. Copy it carefully, and try to explain the various 

 elevations and depressions with reference to the events in 

 the cardiac cycle. 



3. Blood Pressure in Man. Make an observation of the 

 arterial blood pressure of a companion by the 



Riva Rocci Instrument. 



(a) Examine the manometer and see that the cap is removed 

 and that the mercury is at zero. 



(6) Enclose the upper arm of the subject in the armlet and, 

 with the arm horizontal and at the level of the heart, place 

 one finger on the radial pulse and raise the pressure in the 

 instrument some 3 cm. above the point at which the pulse 

 disappears. (Take care not to pull on the tube.) 



(c) Release the pressure gradually and note carefully the 

 exact height of the mercury at the moment when the pulse 

 returns at the wrist. This is the maximum systolic pressure. 



