424 EXPERIMENTAL PHARMACOLOGY 



Have you shown all three stages of the heart action in your 

 experiment I What general conclusions can you draw from 

 the experiment '! 



EXPERIMENT CXXXII. 



Adrenaline, Potassium Chloride, Digitoxin, Strophanthin. 

 (Cat, Rabbit, Dog: Heart Perfusion Langendorff 



Method.) 



1. Set up your apparatus with great care in the manner 

 shown in Fig. 340. Prepare several liters of stock salt solu- 

 tion (Locke's preferred). Place two liters of the solution 

 in the pressure bottle and heat the water bath to 39 de- 

 grees centigrade. Place water in the heart warmer (a hot 

 water funnel may be substituted for the cheap heart warm- 

 er here shown) and heat the warmer to 39 degrees centi- 

 grade. 



When all apparatus is arranged, including the adjust- 

 ment of the cannula (lower end of a glass T-tube with a 

 neck drawn on it) for insertion into the aorta, then etherize 

 the animal and connect a burette to one femoral vein. A 

 straight cannula is placed in one carotid pointing toward 

 the heart to bleed the animal. Draw off as much blood as 

 will flow readily out of the carotid and whip this until the 

 fibrin is all removed. Meanwhile siphon off a liter and a 

 half of the warmed salt solution from the pressure bottle 

 and inject a liter or more of the warm solution into the 

 femoral vein. This will revive the animal somewhat and it 

 may then be bled further from the carotid. All the blood is 

 carefully saved, whipped free from clots, filtered through 

 cloth or cotton and placed in the pressure bottle (which con- 

 tains now one-half liter of warmed salt solution). This 

 mixture of whipped blood and salt solution forms the stock 

 perfusion fluid. More salt solution can be added to it to 

 bring the volume up to four or five times its original 

 amount or more. 



