The Descent of Man

quently be prolonged to two or three; and she
would sometimes change from C sharp and D,
to C 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
very 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 shews
some confusion on the subject; a noise is the
sensation resulting from the co-existence of
several aerial "simple vibrations" of various