602 APPENDIX 



EQUILIBRIUM SENSE 



Compensating Movements. Let the subject with head erect ro- 

 'tate his body for 15 seconds about the vertical axis. When rota- 

 tion is stopped, note the movements of the eyeballs and the arms 

 and legs. Describe the after-sensation. 



Influence of Vision on the Maintenance of Equilibrium. Try to 

 stand on one foot for a minute with the eyes closed. Repeat the 

 trial with the eyes open. Record the experiences. 



HEARING 



Threshold. In a quiet room determine the greatest distance at 

 which the subject, who sits with eyes closed and a hand pressed 

 tightly over the right ear can hear the ticking of a watch held 

 opposite the left ear. Repeat the experiment with the right ear, 

 holding the left ear tightly closed. 



Bone Transmission. Hold a ticking watch between the teeth. 

 Close both ears with finger-tips. Note the effect on loudness of 

 closing both ears. 



Unstop one ear. Compare the loudness in the two ears. 



Spate Perception. Let a student click together two coins in 

 various positions with reference to the ears of another student, who 

 acts as subject and keeps his eyes closed. The subject should point 

 in the direction to which he refers the sound. Compare the ac- 

 curacy of judgment at the sides with that in the median plane. 



With a finger-tip stop the ear on one side, and observe whether 

 the power of localizing sound is diminished. 



TASTE 



Localization. Apply to different parts of the tongue samples of 

 the following solutions: a solution of quinine sulphate (bitter), a 

 5 per cent solution of cane sugar (sweet), a 10 per cent solution of 

 NaCl (saline), and a 1 per cent solution of acetic acid (sour). Note 

 the region on the tongue on which each substance is tasted most 

 acutely. 



Let the student wipe the surface of his tongue as dry as possible, 

 and then let another student apply crystals of salt and of sugar to 

 the dry surface. 



Undissolved substances are not tasted. 



