SPECIAL SENSES 



LXV. NERVE ACTION. 



Apparatus. A stop watch, pencil, paper. 



Directions. Let the teacher write a vowel on a piece of 

 paper which he shall keep covered. Arrange the class in a 

 circle. Station a boy beside the teacher with a stop watch. 

 Proceed as follows: The teacher shows the vowel to the 

 pupil on his right, who whispers it to the pupil on his right as 

 quickly as possible, and so on around the circle to the teacher 

 again. All this as rapidly as possible. Let the, boy with 

 the watch release the stop at the second when the teacher 

 exposes the letter to the pupil on his right, and stop it again 

 when the last pupil repeats the letter to the teacher. Divide 

 the time elapsed by the number of pupils. The result will 

 represent the average reaction time of each pupil. Change 

 the arrangement of the pupils and note whether the time 

 varies. What muscular action does each pupil perform in 

 receiving and transmitting the sound? What sensory nerves 

 are employed? what motor nerves? 



NOTE. In order to bring out various sensation reactions this ex- 

 periment may be varied in many ways which will suggest them- 

 selves to the teacher. 



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