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EXPERIMENTAL PHARMACOLOGY 



Arrange all writing points on the drum and take a few 

 inches of normal record. How does this record of blood- 

 pressure and respiration compare with that obtained when 

 you used an ordinary ether bottle to maintain the 

 anesthesia? 



3. While the anesthesia is moderately light but per- 

 fectly regular, inject just enough oxygen to run the animal 

 for about three minutes. Then with a screw clamp close 

 off the injecting (oxygen) tube and change the oxygen 



Fig. 120. At the place marked "normal" the animal was breathing naturally. No 

 drug had been administered and the animal was lying quietly on the table. At the point 

 indicated some nitrous oxide was given. The respiration at once becomes deeper and 

 more rapid. 



tank for a nitrous oxide tank. Open the screw clamp on 

 the injecting tube and run in as much N 2 as is possible 

 without stretching the bath cap. This should be perfectly 

 free to rise and fall and should not be under any tension. 

 If the cap is stretched the animal cannot breathe well for 

 the mechanical obstruction and may die. The drum runs 

 at a slow speed as the N 2 is run in. How does this affect 

 the blood-pressure and respiration? How does this com- 

 pare with the injection of a drug through the femoral vein? 



