DUDGEON'S SPHYGMOGRAPH. 



235 



of an inelastic strap, carefully regulating the pressure 

 which can be graduated from 1 to 5 ounces by means of 



Fig. 109. Dudgeon's Sphygmograph. 



Fig. 109a. Ludwig's Sphygmograph, made by Petzold, of Leipsig. 



