272 



THE CIECULATION IN THE BLOOD-VESSELS [CH. XXI. 



is investigated is near the heart, a venous pulse is exhibited on the 

 tracing, with small waves as before corresponding to heart-beats, and 



Fia. 273. Normal tracing, somewhat magnified, of arterial pressure in the rabbit obtained with the 

 mercurial kymograph. The smaller undulations correspond with the heart-beats, the larger curves 

 with the respiratory movements. The abscissa or base line, which on this scale would be several 

 inches below the tracing, is not shown. (Burdon-Sanderson.) 



larger waves to respiration, only the respiratory rise in pressure now 

 accompanies expiration. 



The capillary pressure is estimated by the amount of pressure 



FIG. 274. A fown of Pick's Spring Kymograph, a, Tube to be connected with artery ; c, hollow spring, 

 the movement of which moves ft, the writing lever ; e, screw to regulate height of 6 ; d, outside 

 protective spring ; g, screw to fix on the upright of the support. 



necessary to blanch the skin ; this has been done in animals and men 

 (v. Kries, Koy and Brown). 



Other manometers are often employed instead of the mercurial 

 one. Tick's is one of these. The blood-vessel is connected as before 

 with the manometer, and the pressure got up by the use of a syringe 



