THE SECRET OF THE WILLOW WREN 131 



due to the human emotions which they express 

 or seem to express. If the voice simulates that 

 of a maniac, or of a being tortured in body or mind, 

 or overcome with grief, or maddened with terror, 

 the blood-curdling and other sensations proper 

 to the occasion will be experienced; only, if we 

 are familiar with the sound or know its cause, the 

 sensation will be weak. Similarly, if in some deep, 

 silent wood we are suddenly startled by a loud 

 human whistle or shouted " Hi ! " although we 

 may know that a bird, somewhere in that waste 

 of foliage around us, uttered the shout, we yet 

 cannot help experiencing the feelings a combina- 

 tion of curiosity, amusement, and irritation which 

 we should have if some friend or some human being 

 had hailed us while purposely keeping out of sight. 

 Finally, if the bird-sounds resemble refined, bright, 

 and highly musical human voices, the voices, let 

 us say, of young girls in conversation, expressive 

 of various beautiful qualities sympathy, tender- 

 ness, innocent mirth, and overflowing gladness 

 of heart the effect will be in the highest degree 

 delightful. 



Herbert Spencer, in his account of the origin 

 of our love of music in his Psychology, writes : 

 " While the tones of anger and authority are harsh 



