426 



EXPERIMENTAL PHARMACOLOGY 



When no more blood can be obtained from the animal 

 (by injecting salt solution) then quickly open the chest by a 

 median incision with tinner's snips and carefully excise the 

 heart and lungs. Do not injure the vessels or tissues of the 

 heart and watch that the auricles are not cut away. The 

 aorta should be left an inch or more long. Cut off the lungs 

 and free the heart as much as possible from fascia but do 

 not tear the vessels. Tie all the large branches of the aorta, 

 slip the main aortic trunk over the perfusion cannula (do 



R. Ventricle 



Brachiocephalic Art. 

 R Auricle R.Subclavian Art. 



Precava 



^BU" 



R.Carotid Art. 



Postcava 



L.ventricle 



L Auricle 

 Pulmonary vein 



LCarotid Art. 

 LSubclavianArt. 



Ductus arteriosus 

 Pulmonary Art. 



Fig. 341. Cat's heart. 



not insert the cannula far enough to interfere with the 

 semilunar valves or the coronary arteries) and tie the can- 

 nula in. Let the air all out of the perfusion tubes (by open- 

 ing the outlet and running down some of the perfusion fluid 

 while the aorta just below the cannula is closed by a bull- 

 dog). Remove the bull-dog and start the perfusion. Oxy- 

 gen should be started to bubbling slowly through the stock 

 solution. (Compressed air may be used instead of oxygen.) 

 The temperature of the perfusion solution should be kept at 

 about 39 degrees centigrade. The heart may not beat at 

 first, but after a time the beats will begin and soon become 



