306 EXPERIMENTAL PHARMACOLOGY 



tares does nicotine act and what is the nature of this ac- 

 tion? Do your records show this? Inject another dose of 

 nicotine of such size as your animal will probably tolerate 

 well. 



Stimulate the vagus nerve and see how this affects the 

 heart. Do you get an inhibition! If so give another dose 

 of nicotine and again stimulate the vagus. What are your 

 conclusions! How could you prove this? Observe one pu- 

 pil and stimulate the corresponding vago-sympathetic 

 trunk. Does the pupil contract or dilate! How do you ex- 

 plain this ! What is the action of nicotine on the pupil ? 



Empty the nicotine out of the burette and place arecoline 

 solution (one cubic centimeter equals one-half milligram) 

 therein. Inject one cubic centimeter of arecoline (less if 

 the animal is small) and get a record. Observe the pupil 

 as the drug is run in. Has the nicotine affected the action 

 of this drug in any way? Wait for the drug to act. Inject 

 one-half cubic centimeter of adrenaline to revive the ani- 

 mal (give a second dose if necessary.) 



Empty out the adrenaline and fill the burette with atro- 

 pine solution (one cubic centimeter equals one milligram). 

 Take a normal record and then inject one cubic centimeter 

 (or one and one-half cubic centimeters) of arecoline. 

 When the action is very marked inject one cubic centimeter 

 of atropine. Wait the circulation is slow. Do you get 

 the proper response to the drug ? How do you explain this 1 

 Inject one-half cubic centimeter more of atropine. 



Empty out the arecoline and fill the burette with nicotine. 

 Start the drum and inject one cubic centimeter of nico- 

 tine. Does your record correspond with the theoretical 

 action of the drug ? How do you explain this 1 What struc- 

 tures are involved? Kill the animal with a large dose of 

 nicotine. Discuss in full the counteraction of these drugs. 

 Open the chest, dissect out the left pulmonary artery and 

 place a ligature under it. (See Figs. 274, 275, 276, and 

 277.) Slip this ligature as far out on the artery as possible 



