LESSON XIII. ACTION OF ADRENALINE AND 

 OF SALTS ON THE HEART. 



1. Perfusion of heart and effect of adrenaline. 

 Expose the heart of a pithed frog. Cut through the peri- 

 cardium and the tissue on either side of the aortae. Pass 

 a thread under the aortse and pull it backwards. Cut out 

 the larynx. Turn the ventricle forwards, cutting through 

 its ligament. Cut away the thin membrane overlying 

 the inferior vena cava, this requires care to avoid cut- 

 ting the vessel. With fine pointed scissors pick up the 

 wall of the vein close to the liver, cut a small hole in it 

 with fine pointed scissors. Remove the blood with a 

 sponge and insert the point of a cannula of the shape 

 shown in Fig. 23 (Ca.) and tie it in. (If this fails, make 

 a cut in one of the auricles as far as possible from the 

 ventricle and tje the cannula in this.) Cut across the 

 aortse, and cut out the heart attached to the cannula. 



Clamp the tip of the ventricle with the small wire 

 clamp (Fig. 23 CT.), pass a thread through the loop of 

 the clamp and fix the cannula and the heart as in Fig. 

 23, taking care that the lever is at such a height that by 

 moving the drum up or down the whole of the blackened 

 paper can be used. Put a small glass dish on the table 

 under the heart. Connect a Mariotte's bottle (cp. 

 Fig. 24 M ) containing Ringer's fluid, with the cross 

 piece of the cannula, the connecting rubber tubing 

 having a clamp on it. Set the drum so that the heart 

 tracings are only a few mms. apart. 



Raise the bottle so tfeat the lower end of the tube in 

 it is about 2 cm. above the level of the heart. Open the 



