314 



TEXT-BOOK OF PHYSIOLOGY. 



the blood can be made to flow directly into the distal portion of the 

 artery across the base or indirectly by way of the glass tube. Pre- 

 vious to the intercalation of the tube it is filled with serum or normal 

 saline solution. With the turning 

 of the cocks at B the blood enters '* 



the glass tube and drives the serum 

 ahead of it into the arterial system. 

 From the difference in time between 

 the moment the blood enters and 

 the moment it leaves the tube and 

 from the length of the tube the 

 velocity is determined. 



FlG. 147. VOLKMANN'S HEMODROMOMETER. 



C, C. Arterial cannulas. 



FIG. 148. LUDWIG AND DOGIEL'S 

 RHEOMETER. X, Y. Axis of 

 rotation. A, B. Glass bulbs. 

 h, k. Cannulas inserted in the 

 divided artery, e, e v rotates 

 on g, /. c, d. Tubes. 



, t \ rl T meter of Lud ^g (Fig. 148) is constructed 



on the same prmaple, but instead of the glass tube having the same 



