Книга только для ознакомления
.
The power of erecting and directing the shell of the ears to the
various points of the compass, is no doubt of the highest service to
many animals, as they thus perceive the direction of danger; but I
have never heard, on sufficient evidence, of a man who possessed
this power, the one which might be of use to him. The whole external
shell may be considered a rudiment, together with the various folds
and prominences (helix and anti-helix, tragus and anti-tragus, &c.)
which in the lower animals strengthen and support the ear when
erect, without adding much to its weight. Some authors, however,
suppose that the cartilage of the shell serves to transmit
vibrations to the acoustic nerve; but Mr. Toynbee,*(2) after
collecting all the known evidence on this head, concludes that the
external shell is of no distinct use. The ears of the chimpanzee and
orang are curiously like those of man, and the proper muscles are
likewise but very slightly developed.*(3) I am also assured by the
keepers in the Zoological Gardens that these animals never move or
erect their ears; so that they are in an equally rudimentary condition
with those of man, as far as function is concerned. Why these animals,
as well as the progenitors of man, should have lost the power of
erecting their ears, we can not say. It may be, though I am not
satified with this view, that owing to their arboreal habits and great
strength they were but little exposed to danger, and so during a
lengthened period moved their ears but little, and thus gradually lost
the power of moving them
|
