88 



Chapter VI 



under two headings, (a) his method for gauging the functional 

 activity, and (b) that for measuring the oxygen. 



The research was performed upon the excised heart of the cat in 

 every case. A rubber balloon was introduced into the cavity of the 

 ventricle, and the balloon was distended with water at a known 

 pressure. Thus it was possible (1) to estimate the pressure against 

 which the heart was working, and (2) by taking a tracing to obtain 

 a record of (a) the rise of pressure during systole, and (b) the rate of 

 the pulse. 



17cm 



A 



E 



CJ 



O 



FIG. 52. Eohde's arrangement for measurement of the functional activity of the 



warm-blooded heart. 



H rubber balloon in left ventricle. A= burette for measuring constant pressure. B = 

 pressure bottle. C = burette for measurement of capacity of balloon during isometric 

 contractions. D = quick-silver valve. F-M = Frank's " Feder manometer." W = 

 wall of incubation chamber. Bore of tubing = 0'6 0'7 cm. 



The apparatus is sufficiently described by the figure, from which it 

 will be seen that it is possible, by appropriately turning the taps, 



(a) to make the heart beat against a known pressure isotonically, or 



(b) by preventing the fluid from leaving the rubber bag to make the 

 beat isometric and that with any given volume of fluid in the bag. 



The technique for measuring the oxygen was also very different 

 from that used by us. In the first place the heart was perfused not 



