SCOPOLAMINE, PILOCARPINE, ATROPINE 273 



ameter as it enters tlie eye ball. Place the tips of the elec- 

 trodes on the nerve and carefully work the points into the 

 substance of the nerve trunk. "Watch the pupil closely and 

 stimulate. Is there any action? Perhaps the animal has 

 been dead too long. Do you think of any other reason? 

 Master the technic of the operation for you will want to 

 repeat it later. What is the innervation of the iris? 

 How do these nerves get into the eye? Can you reach them 

 in the way you have proceeded here? What are mydri- 

 atics? Myotics? Cycloplegiacs ? 



EXPERIMENT LXIV. 

 Scopolamine. (Frog: General Symptoms.) 



1. Into the anterior lymph sac of a frog inject one 

 cubic centimeter of scopolamine (one cubic centimeter 

 equals five milligrams). Put the animal in a quiet place 

 and observe the symptoms produced. "What conclusions 

 can you draw? Examine the pupils from time to time and 

 note the action on the lymph heart beats. Give a larger 

 dose if necessary to bring on marked symptoms. 



EXPERIMENT LXV. 

 Pilocarpine, Atropine. (Frog: Heart and Vagus Nerve.) 



1. Pith a frog, take a normal heart tracing showing- 

 vagus and crescent inhibition and then while the drum is 

 running at a fairly slow speed begin to drop on to the heart 

 pilocarpine (nitrate or hydrochlorate) solution (one cubic 

 centimeter equals one milligram). Watch for a slowing 

 of the beat. The heart may be entirely stopped. How do 

 you account for this? When the slowing has become very 

 marked pour about three or four drops of atropine solu- 

 tion (one cubic centimeter equals one milligram) on to the 



