1082 



PHYSIOLOGY 



K 



contained, so as to register changes in the volume of the ventricle. A large 

 number of different forms of apparatus have been devised for these purposes. 



In another method the fluid is allowed to flow through the whole heart, 

 passing in by the sinus and out by the aorta. Here again the activity of the 

 heart may be registered either by recording the pulsations in the arterial column 

 of fluid or by connecting a tambour or piston recorder with the vessel in which 

 the heart is contained. 



The heart of warm-blooded animals can also be investigated by a somewhat 



similar method. It was shown by Porter that the 

 mammalian heart, could be kept alive by transfusing 

 defibrinated blood through the coronary vessels, 

 and Locke found that the same results could be 

 obtained by using oxygenated Ringer's solution, 

 modified so as to have the same tonicity as mam- 

 malian blood. A convenient apparatus for this 

 purpose has been devised by Brodie. 



The apparatus (Fig. 444) consists of a chamber 

 A to contain the heart, and of a tube B, through 

 which the perfusion fluid is carried to the heart. Both 

 are enclosed in a large outer jacket c, through which is 

 kept flowing a stream of water at body temperature. 

 The chamber A is bell-shaped and is fitted into the 

 jacketing tube c by a ground-glass joint D. Its 

 upper orifice is closed by a piece of rubber tubing 

 of such size that the perfusion tube B slips through 

 it easily. By means of the glass handle F, fused 

 into the tube about half-way down, B can be drawn 

 up or lowered into any desired position. To its lower 

 end the heart cannula is attached by a ground joint. 

 Its upper end is fitted, by a second ground joint, 

 with a small bulb w, with two tubes, B, and s, fitted 

 into it. These latter are connected by rubber tubing 

 with aspirators containing the solutions to be 

 perfused. The lower half of the tube B is nearly 

 filled up with a thermometer L, the bulb of which 

 projects into the heart cannula T. The upper half is 

 FIG. 444. Brodie's perfusion almost filled with a piece of glass tubing sealed at 

 apparatus for the mamuia- both ends, so that the perfusion fluid passes in a 



thin layer down the tube and thus offers a large 

 surface for heating purposes. Also by filling the 

 interior of the tube in this way its capacity is reduced to a very small amount. 

 The large outer tube c is kept supplied with warm water, entering through 

 the tube G and overflowing through a side-tube at the top into a wide T-piece N. 

 By raising or lowering this T-piece the level of the water in the jacket is adjusted. 

 The water-supply comes from a cold-water tap, but on its passage to G passes 

 through a metal spiral heated by a Bunsen burner. By varying the rate of flow 

 and the position of the burner the temperature of the water can be regulated 

 with considerable accuracy. The upper end of the supply-tube G is provided 

 with a thermometer so that the temperature of the inflowing water can be seen 

 and regulated. 



In using the apparatus the heart cannula is removed, and the tube B is then 

 passed through E and pushed down until its lower end issues just below the level 

 of the chamber A. The circulation of the warmed water through the jacket is 

 then started and adjusted to the proper temperature. One of the rubber tubes, 



lian heart. 



