ACTION OF ATROPINE 269 



of the pupils carefully. Place one eye in a watch glass full 

 of normal salt solution and the other in atropine solution. 

 Place both glasses aside for ten or twenty minutes. Then 

 again compare the size of the pupils. Do you note any va- 

 riations? Explain the results. 



EXPERIMENT LX. 

 Atropine. (Frog: Muscle and Nerve.) 



1. From the frog used in Experiment LIX prepare two 

 muscle nerve preparations from the sciatic nerves and gas- 

 trocnemius muscles. Fill a watch glass with atropine 

 solution and place the nerve of preparation A and the 

 muscle of preparation B in the solution. From time to time 

 stimulate both nerves with single shocks and determine 

 whether or not atropine affects either nerve trunks or stri- 

 ated muscle. Compare this with the action of curara. 

 Stimulate the muscles directly a few times. What con- 

 clusions can you draw? 



EXPERIMENT LXI. 

 Atropine. (Turtle: Heart and Vagus Nerve.) 



1. Repeat the experiment on the heart and vagus inner- 

 vation described in Experiment LIX, 1, on the turtle. What 

 conclusions can you draw from your results? 



EXPERIMENT LXII. 



Atropine. (Cat, Guinea Pig, Rat, Dog, Pigeon, or 



Chicken: Pupil.) 



1. Secure a dog, guinea pig or rat and a pigeon or 

 chicken. Into the right eye of each animal pour several 

 drops of a one per cent solution of atropine with a medicine 

 dropper. Place the animals aside and examine from time 



