240 THE NERVOUS SYSTEM 



Nerve Action 



Materials: Frog; feather; watch with second hand (pref- 

 erably stop-watch). 



1) lie flex Action: a) Feign blow at a person's eye, having 

 warned him that he is not to be struck, b) Tickle inside of 

 nose with feather. 



2) Voluntary Reaction: a) Arrange class in a circle so that 

 a signal may be passed from one to another by touching hands. 

 Let instructor, as member of circle, give signal by touching 

 hand of neighbor, who transmits it to next, and so on. Finally, 

 instructor receives signal and determines time of transmission. 

 This time, divided by number in circle, gives average reaction 

 time of its members. 



b) Repeat with such modifications as shutting eyes; whisper- 

 ing a sound instead of touching; dividing class into competing 

 halves, etc. 



3) Place live frog on table and note its reactions (breathing, 

 winking, jumping, etc.) to varying stimulations (touching, 

 turning, feeding, etc.). 



