FACULTIES OF THE MIND. 984 
they do not hear the sounds which others utter, they have 
consequently no guide to their power of imitation. By 
operating upon their natural cries, and by the help of signs, 
they may be taught to speak, but their voice is unequal 
and harsh. It is equally possible to be able to distinguish 
sounds, and, to a limited extent, the things which they are 
intended to represent, without possessing the capability of 
voice necessary for imitating them. This is conspicucus- 
ly the case in the dog and horse, which understand the lan- 
guage of command, encouragement, and approbation, and 
yet are incapable of producing any analogous sounds. The 
parrot, mock-bird, and many others, can learn to imitate 
many kinds of sound, without comprehending the things of 
which they are the signs. By much trouble, however, 
they may be made to perceive the connection, and even to 
avail themselves of their knowledge, to express their wants 
or desires. It is necessary, however, to state this impor- 
tant limitation, that these sounds communicate information 
to man alone, their instructor, and do not constitute any 
channel of communication between individuals of their own 
species. 
The most obviously acquired sounds in the mferior ani- 
mals, may be observed in the Singing of Birds. Vf a 
young linnet, for example, be taken from the nest, and 
brought up in the company of the nightingale or lark, in- 
stead of learning to utter the musical notes of its own spe- 
cies, it imitates the song of that bird which it has been ac- 
customed to hear, more or less perfectly, according to the 
‘state of its organs. In this mode of educating singing birds, 
there is frequently displayed a power of selection on the 
part of the young scholar. |‘ I educated, (says the Hon- 
ourable Datnes Barrincron*,) a nestling robin under 

* Experiments and Observations on the Singing Birds. Phil. Trans. 
vol. Ixiii. p. 258. 
