138 WOOD NOTES WILD. 



Genesis of Bird Song. — Contin. 



own addition to the glorious inheritance." — Torrey, B. : Birds in the 

 Bush, p. 47. 



" Let us for a moment try to conceive how this process may have been 

 accomplished. We presuppose a certain amount of the power of vocalization 

 at different heights or pitches, the results of social needs, etc. We further 

 assume, as the correlative of this, the existeuce of a nascent sensibility to 

 differences of pitch, also a feeling of preference for certain kinds of timbre 

 over others. The circumstances of wooing, with its eager rivalries, would 

 serve to bring out the existing powers of vocalization to their fullest. 

 The more striking and attractive the sounds produced by a particular 

 male, the more likely would it be to win his mate. Now a voice might 

 be more impressive, either through its greater intensity, or through its 

 more agreeable timbre, or finally through its greater variety of tone, or 

 range of pitch. And thus the fortunate possessors of voices having these 

 superior qualities would, other things being equal, outdo their rivals. 

 Now this triumph of rich-voiced individuals in the contests of love would 

 have important after-results. If from generation to generation the females 

 of a particular species continue to choose males with fine voices, there 

 would be a gradual improvement of vocal powers generally, according to 

 Mr. Darwin's well-known principle of sexual selection. By this means 

 any natural superiorities of voice would tend to be preserved, and the 

 average vocal capabilities of each succeeding generation increased. Nor 

 is this all. Along with this increased power of producing tones, there 

 would go an increased sensibility to the pleasurable effects of tone. And 

 this would be brought about in two different ways. In the first place the 

 continual performances of the male singers would, by exercising the 

 functions of the ear, tend to raise its sensibility. In the second place it is 

 plain that superior vocal powers in the male would, as a rule, co-exist with 

 superior auditory sensibility ; for the movements of the voice are always 

 guided by the effects on the ear. And thus sexual selection would tend 

 to improve the musical ear as much as the musical voice. In this way, 

 we think, might have been developed among all musical animals, including 

 the ancestors of man, the power of producing and of appreciating purity 

 of tone, richness of timbre, rhythm, and melody. Little by little, the 

 vocal organs would attain the necessary complexity, flexibility, and means 

 of adjustment, and little by little the ear would acquire the needed 

 nervous elements and their connections." — Sully, J., in article before 

 quoted. (See Index, Sully, J.) 



It is hoped that Mr. SuUy will carry out his intention to publish this 

 careful, admirable paper in book form. 



