LX.] 



HEART-VALVES. 



289 



ADDITIONAL EXERCISES. 



8. Polygrapn of Knoll and Rothe. — This is a most convenient apparatus, 

 both for work in the laboratory and at the bedside. Moreover, it is so 

 arranged that two tracings can be taken simultaneously. It is made by 

 H. ;^the, Wenzelbad, Prague. It can be used to take simultaneously 



Fia. 210.— U. Tracing of the cardiac impulse, the respiratory movements of the chect 

 not being arrested. 



cardiac im])ulse and a pulse tracing, or respiratory movements and a pulse 

 tracing, or two ])ulse tracings. 



Fig. 209 shows the ariangement of the apparatus. It consists of a drum 

 [* F) moved Ity clockwork within the box D. K is a catch for setting D in 



FiCk an.— Showing the Method of Fixing the K«ceivlng Tambour of Eothe's 

 Polygraph on an Artery. 



motion. M is a time-marker beating seconds. H, H are two Marey*8 

 registering tambours adjustable on the stand C. B is a tambour which can 

 be fixed over an artery or over the cardiac impulse, while A is a bottle-shaped 

 caoutchouc bag which can be strapped to the body for studying the respiratory 

 movements. 



