610 MANUAL OF PHYSIOLOGY. 



b) the difference of distinctness with which they are heard by one 

 or other ear. When we cannot form any idea of whence a sound 

 comes we usually turn our heads one way or the other in order to 

 present one ear more directly to the origin of the sound. When 

 a sound is either directly behind or before us we cannot judge 

 which position it really comes from, unless the head be slightly 

 turned to one side or to the other. 



