HEAKT AND LUNGS OF MAMMAL. 143 



Place the funnels in the rings. Lay the heart, now 

 wholly severed from the lungs, on its front surface. Con- 

 nect one funnel, by rubber and glass tubing, with the left 

 auricle by the tube already in the pulmonary vein ; con- 

 nect the other funnel with the right auricle through the 

 vena cava superior ; ligature the vena cava inferior. Lay 

 the heart in a basin and pour water into the funnels ; hold 

 the heart with the two hands and compress it, repeatedly 

 adding water. In this way the clotted blood usually 

 present in the right ventricle may be washed out. If 

 this remain, it may interfere with later experiment. Con- 

 nect the aorta with the funnel which leads to the right 

 auricle, by means of a glass tube which bends over the 

 edge of the funnel, thus holding itself in place by the 

 hook, and emptying into this funnel any liquid which 

 escapes from the tube. 



In like manner have a bent glass tube, from the pul- 

 monary artery, hooked over the edge of the funnel leading 

 to the left auricle. 



Pour water into one of the funnels and compress the 

 heart to imitate its natural contraction; observe where 

 the liquid next appears; add more water and follow it 

 around to its starting-point. A little ink may be poured 

 into one of the funnels and traced around, as the heart is 

 worked, to its starting-point. 



That there is no direct connection between the two 

 halves of the heart may be shown by letting the liquid 

 from each artery empty into the auricle of the same side 

 of the heart. Different colored liquids may be used in the 

 two funnels. 



