208 Canadian Record of Science. 



ously from the central and peripheral ends of the external 

 jugular, by inserting one canula into it through the 

 posterior scapular vein, and another through the external 

 maxillary. 



To measure the rate of propagation through the inferior 

 vena cava, one tracing was taken as above from the central 

 end of the external jugular, and the other from the femoral 



Pig. 3. 



vein by introducing a canula into it through the deep 

 femoral. At the end of the experiments the distances 

 of the points on the veins used from the right auricle were 

 measured ; if one indicates the distance of the point near- 

 est the heart by e^, and the distance of the point farthest 

 away by e^^, then the length of vein for which the rate of 

 propagation of the pulse waves is estimated is e^^ — e^. 



Finally, at the end of the experiment the points on the 

 two tracings, corresponding to one another in time, were 

 established by causing both levers to write vertical lines,, 

 with the kymograph standing still. The marking of these 

 points was sometimes attended with considerable difficulty^ 

 on account of the waves being less sharp than those of the 

 arterial pulse. 



In most cases, however, a fair number of satisfactory 

 markings could be made. An example of these markings 

 is seen in Fig. 4. The distance apart of the vertical lines 

 indicates how much later the wave began in the distal 

 part of the vein than in the central, the exact time being- 

 estimated by comparison with the horizontal line between 

 the tracings, on which seconds are marked. 



