350 EXPERIMENTAL PHARMACOLOGY 



EXPERIMENT XCII. 

 Cocaine. (Frog: Central Nervous System.) 



1. Pith a frog (cerebrum only) and wait a while for the 

 animal to recover from the shock. Then inject into the 

 anterior lymph sac one cubic centimeter of cocaine hydro- 

 chloride solution (one cubic centimeter equals five milli- 

 grams one-half per cent). 



Observe the symptoms produced and save the animal for 

 several hours (if it lives) to note the later action of the 

 drug. AVhat conclusions can you draw! Do you find any 

 evidence of central nervous stimulation! How is the rate 

 of beat of the lymph hearts affected! 



EXPERIMENT XCIIL 



Cocaine, Physostigmine. (Rabbit, Cat, Dog, Pigeon, 

 Sparrow, Chicken, Rat: Action on Pupil.) 



1. Into the right eye of as many of the above animals as 

 you can obtain inject ten drops of a one per cent solu- 

 tion of cocaine hydrochloride. Open the lids, drop in the 

 solution and try to hold the eye open a while to insure ab- 

 sorption. Wait ten minutes (examine the pupils from time 

 to time) and then inject into the left eye of each animal ten 

 drops of a solution of eserine (one cubic centimeter equals 

 five milligrams). Observe both pupils carefully from time 

 to time and when the actions of the drugs come on try the 

 light reflex to see if the pupil contracts when a bright light 

 (pocket flash light, lighted match, or It right light from a 

 window, etc.) is suddenly thrown into the eye. On what 

 does this light reflex depend! Explain in detail the nerv- 

 ous paths involved in its production. What differences do 

 you note in the actions of the two drugs! On what struc- 

 tures does each act and how! How do these drugs affect 

 the intraocular pressure! How is this brought about! 



