First—By _vocal intonations_ (as in man) in brutes and birds: and I may
remark that all brutes possess a tongue, larynx, and vocal cords; and
that birds have these also, with the exception that the bird’s larynx
(syrinx) is rather modified from that of man and the mammalia; still we
know its perfection; and we know how the parrot can use it.
Secondly—_By gesture_ and visual regard, as seen in dogs, and in birds.
Thirdly—_By means of sounds other than vocal_, as is witnessed in the
stamping on the ground by various animals to intimate danger. Also the
noises of insects made by rubbing their wing-cases (elytra) together,
as in the cricket, etc.
Fourthly—_By means of touch_, as in the cases of ants, bees, and other
insects, which can convey meanings by crossing their antennæ.
Fifthly—Other signs, etc., perhaps, with which we have no acquaintance,
and can form no conjecture.
Sixthly—Information can also probably be ascertained by smell.
By any one of these means separately, or together, it doubtless is
possible for very numerous species of creatures to communicate with
their kind by means of a language,—little articulate it may be—but
still more or less articulate, according to endowment.
Let us now consider animal language by whatever mode effected; and to
do so I propose to divide the subject into two sections.