274 



PHYSIOLOGY 



CHAP. 



heart. A 7 ierordt (1858) was the lirst to construct an apparatus 

 for the study of these oscillations. Vierordt's haemotachometer is 

 based on the principle of the hydrostatic pendulum, used by 



FIG. 113. Chaiiveau's haemodrometer. Left-hand figure shows the instrument as a whole ; 

 right-hand, a vertical section of it. (Explanation in text.) 



engineers to measure the rate of a stream of water. His method 

 was perfected and developed by Chauveau (1860), who constructed 

 a very ingenious recording apparatus on the same principle, which 

 he termed a haemodromograph. 



Fig. 113 shows this apparatus as a whole on the left, and in 



