The rabbits on the island of Sor, near Senegal, have white flesh, and are
well tasted, but do not burrow in the earth, so that we may suspect their
digging themselves houses in this cold climate is an acquired art, as well
as their note of alarm, (Adanson's Voyage to Senegal).

The barking of dogs is another curious note of alarm, and would seem to be
an acquired language, rather than a natural sign: for "in the island of
Juan Fernandes, the dogs did not attempt to bark, till some European dogs
were put among them, and then they gradually begun to imitate them, but in
a strange manner at first, as if they were learning a thing that was not
natural to them," (Voyage to South America by Don G. Juan, and Don Ant. de
Ulloa. B. 2. c. 4).

Linnæus also observes, that the dogs of South America do not bark at
strangers, (Syst. Nat.) And the European dogs, that have been carried to
Guinea, are said in three or four generations to cease to bark, and only
howl, like the dogs that are natives of that coast, (World Displayed, Vol.
XVII. p. 26.)

A circumstance not dissimilar to this, and equally curious, is mentioned by
Kircherus, de Musurgia, in his Chapter de Lusciniis, "That the young
nightingales, that are hatched under other birds, never sing till they are
instructed by the company of other nightingales." And Jonston affirms, that
the nightingales that visit Scotland, have not the same harmony as those of
Italy, (Pennant's Zoology, octavo, p. 255); which would lead us to suspect
that the singing of birds, like human music, is an artificial language
rather than a natural expression of passion.

X. Our music like our language, is perhaps entirely constituted of