44 TSE DESCENT OF MAN. 



certain rodents utter musical sounds. Singing mice have 

 often been mentioned and exhibited, but imposture has 

 commonly been suspected. We have, however, at last a 

 clear account by a well-known observer, the Rev. S. Lock- 

 wood,* of the musical powers of an American species, the 

 Hesperomys cognatus, belonging to a genus distinct from 

 that of the English mouse. This little animal was kept in 

 -confinement, and the performance was repeatedly heard. 

 In one of the two chief songs, " the last bar would fre- 

 quently be prolonged to two or three; and she would some- 

 times change from C sharp and D to natural and D, then 

 warble on these two notes awhile, and wind up with a quick 

 chirp on C sharp and D. The distinctness between the 

 semitones was very marked and easily appreciable to a 

 good ear." Mr. Lockwood gives both songs in musical 

 notation; and adds that though this little mouse "had no 

 ear for time, yet she would keep to the key of B (two flats) 

 and strictly in a major key. . . . Her soft clear 

 voice falls an octave with all the precision possible; then at 

 the wind-up it rises again into a quick trill on C sharp 

 and D." 



A critic has asked how the ears of man, and he ought to 

 have added of other animals, could have been adapted by 

 selection so as to distinguish musical notes. But this 

 question shows some confusion on the subject; a noise is the 

 sensation resulting from the co-existence of several aerial 

 ( ' simple vibrations " of various periods, each of which 

 intermits so frequently that its separate existence cannot be 

 perceived. It is only in the want of continuity of such 

 vibrations, and in their want of harmony inter se, that a noise 

 differs from a musical note. Thus an ear to be capable of 

 discriminating noises and the high importance of this 

 power to all animals is admitted by every one must be 

 sensitive to musical notes. We have evidence of this 

 capacity even low down in the animal scale; thus Crusta- 

 ceans are provided with auditory hairs of different lengths, 

 which have been seen to vibrate when the proper musical 

 notes are struck, f As stated in a previous chapter, similar 

 observations have been made on the hairs of the antennae 

 of gnats. It has been positively asserted by good observers 



*The "American Naturalist, "1871, p. 761. 



{Helmholtz, "Tlworie Phys. de ^ Musique," 1868, p. 187. 



