PRACTICAL EXERCISES 



207 



Fig. 101. Effect of Exercise on the 

 Pulse (Marey). Upper tracing, 

 normal; lower, after running. 



the needle which records the movements of the artery. Or a small 

 glass funnel or thistle-tube connected with a recording tambour may 

 be pressed over the carotid artery. The lever of the tambour writes 

 on a drum, on which at the same time half or quarter seconds are 

 marked by an electro-magnetic signal. 



19. Venous Pulse Tracing from the 

 Jugular Vein. Arrange a recording 

 tambour to write on a drum. Con- 

 nect the tambour with the stem of a 

 small glass thistle-tube or funnel (or 

 with a small metal cup) by a piece of 

 narrow rubber tubing, and apply the 

 cup-shaped end of the thistle-tube 

 over the right jugular bulb of a 

 fellow-student. This lies about i inch 

 external to the right sterno-clavicular 

 articulation, and a little above it. The 

 receiver may have to be moved about 

 a little until the best pulsation is 

 obtained. The ' patient ' should be 



lying down, the shoulders slightly raised, the head on a pillow and turned 

 slightly to the right, in order to relax the right sterno-mastoid muscle 

 (Mackenzie). 



20. Polygraph Tracings. Arrange the polygraph over the radial 

 artery, as with an ordinary sphygmograph, so that the lever will record 

 the radial pulse when the strip of paper is set moving. If the instru- 

 ment has only one tambour, con- 

 nect the tambour to a receiver 

 or thistle-tube over the jugular 

 bulb. The writing-point of the 

 tambour is arranged so as to be 

 immediately below the writing- 

 point connected with the radial. 

 If the polygraph is provided 

 with clockwork to record time, 

 Bet off the time-marker writing 

 fifths of a second. When it is 

 Been that the writing-points are 

 marking properly, start the 

 clockwork which moves the 

 strip of smoked paper. Repeat 

 the observation with the tam- 

 bour connected with the apex- 

 beat. Letter the curves as far 



Fig. 102. Effect of Amyl Nitrite on the as possible as in Figs. 65 and 

 Pulse (Marey). Upper tracing, normal; 66 (p. 149) without at present 

 lower, after inhalation of amyl nitrite. attempting their exact analysis. 



If the polygraph has two tam- 

 bours, simultaneous tracing of the radial pulse, the jugular pulse, and the 

 cardiac impulse, or of the carotid pulse, the jugular pulse, and the apex- 

 beat, may be taken, and other combinations as well. If no polygraph 

 is available, a drum may be employed, the tracings being all taken with 

 thistle-tubes connected with recording tambours. The levers of the 

 tambours must be arranged to write on the drum in the same vertical 

 straight line, or, without making the adjustment quite exact, vertical lines 

 of reference may be drawn through each curve, with the drum at rest, 

 indicating the relative positions of the writing-points. 



