58 



PRACTICAL PHYSIOLOGY 



FIG. 54. Dudgeon's sphygmograph. 



(v) See that the button on the spring of the sphygmograph is over 

 the artery, (vi) Strap the instrument on, varying the tightness 

 of the band to give the best range of movement, (vii) Vary the 



FIG. 55. Marey's sphygmograph. 



