274 



EXPERIMENTAL PHARMACOLOGY 



heart and note the effect on the heart rate. How do vou 



*/ 



explain this? Stimulate the vagus and crescent again. 



2. Cut out both eyes and place one in a normal salt solu- 

 tion, the other in salt solution containing pilocarpine (one 

 cubic centimeter equals five milligrams). Place the eyes 

 aside for ten or twenty minutes and examine the pupils 

 again. Can you detect any pupillary changes? What ex- 

 planation can you offer? 



Fig. 241. Lung tracing from a turtle showing the action of pilocarpine. 



EXPERIMENT LXVL 



Pilocarpine or Arecoline and Atropine. (Frog: 



Circulation.) 



Retinal 



1. Arrange a frog as shown in Fig. 164 and examine its 

 retinal blood vessels with an ophthalmoscope. Find one or 

 two very small vessels, preferably showing a branching so 

 that the individual corpuscles can be seen moving into each 

 division. Get a good notion of the rate of this movement 

 for later comparison. 



Under the skin of the back inject two cubic centimeters 

 of pilocarpine solution (one cubic centimeter equals two 

 milligrams) or arecoline hydrobromide (one cubic centi- 

 meter equals one milligram, Merck and Co.) solution. 



