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EXPERIMENTAL PHARMACOLOGY 



and note carefully what has been removed. Cut the plas- 

 tron loose at each side and remove it. Lift up the intestines 

 and liver and with great care dissect them loose from the 

 lungs. To do this put a cannula (Fig. 233) into the trachea 

 and attach a rubber tube. Then with the mouth blow the 

 lungs up as indicated in the illustration and clamp off the 

 rubber tube. This holds the lungs partially distended and 



Fig. 233. Arrangement of apparatus with a turtle held in a Higgin's turtle frame 

 (of 3/8 inch iron rod with hooks at the corners to which the limbs are tied) for record- 

 ing lung contractions. A very sensitive large-bowled tambour with a large magnification 

 is used, and the lungs are partially inflated by forcing a little air (with the mouth) into 

 the side outlet of the tubing. This puts the tambour and the lung both under moderate 

 tension and in direct communication. When the lung contracts the tambour pointer 

 rises but when the lung relaxes the pointer descends as the rubber membrane on the 

 tambour forces the air back into the lung. Drugs are conveniently administered by in- 

 jection into the heart with a fine pointed hypodermic syringe. 



greatly aids in the dissection. Use great care not to punc- 

 ture the lungs. If you do this, find the hole, lift up the 

 edges of the opening and tie a ligature around the puncture. 



