to visit for a few moments, to look at my experimental plants. This was
always a great disappointment to the dog, as he did not know whether I
should continue my walk; and the instantaneous and complete change of
expression which came over him as soon as my body swerved in the least
towards the path (and I sometimes tried this as an experiment) was
laughable. His look of dejection was known to every member of the
family, and was called his _hot-house face_. This consisted in the head
drooping much, the whole body sinking a little and remaining
motionless; the ears and tail falling suddenly down, but the tail was
by no means wagged. With the falling of the ears and of his great
chaps, the eyes became much changed in appearance, and I fancied that
they looked less bright. His aspect was that of piteous, hopeless
dejection; and it was, as I have said, laughable, as the cause was so
slight. Every detail in his attitude was in complete opposition to his
former joyful yet dignified bearing; and can be explained, as it
appears to me, in no other way, except through the principle of
antithesis. Had not the change been so instantaneous, I should have
attributed it to his lowered spirits affecting, as in the case of man,
the nervous system and circulation, and consequently the tone of his
whole muscular frame; and this may have been in part the cause.
We will now consider how the principle of antithesis in expression has
arisen. With social animals, the power of intercommunication between
the members of the same community, and with other species, between the
opposite sexes, as well as between the young and the old, is of the
highest importance to them. This is generally effected by means of the
voice, but it is certain that gestures and expressions are to a certain
extent mutually intelligible. Man not only uses inarticulate cries,
gestures, and expressions, but has invented articulate language; if,
indeed, the word INVENTED can be applied to a process, completed by
innumerable steps, half-consciously made. Any one who has watched
monkeys will not doubt that they perfectly understand each other s
gestures and expression, and to a large extent, as Rengger
asserts,[201] those of man. An animal when going to attack another, or
when afraid of another, often makes itself appear terrible, by erecting
its hair, thus increasing the apparent bulk of its body, by showing its
teeth, or brandishing its horns, or by uttering fierce sounds.
As the power of intercommunication is certainly of high service to many
animals, there is no _a priori_ improbability in the supposition, that
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