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EXPERIMENTAL PHARMACOLOGY 



two or three hours and see if there is a return to normal. 

 Keep the animal covered with a thin layer of wet cotton. 



EXPERIMENT CXI. 



Pituitrin. (Frog or Turtle: Heart Tracing.) 



1. Pith a frog or turtle and take a normal heart tracing- 

 showing vagus inhibition. Irrigate the heart with some 

 pituitrin solution (1 to 5) and determine the action of the 

 substance on the heart. Is the inhibitory apparatus in- 

 volved in any way ? How is the musculature of the heart af- 

 fected? 



EXPERIMENT CXII. 



Pituitrin. (Turtle: Lung Tracing.) 



1. Arrange a turtle for recording lung tracings. Stimu- 

 late one vagus nerve and see if you get a contraction of the 



Fig. 321. Turtle lung tracing showing the action of pituitrin. 



lung. The magnification of the tambour tracing should be 

 large. Take a normal and inject into the heart one cubic 

 centimeter of pituitrin solution (1 to 5). AVhat conclusions 

 can vou draw from vour results? 



