The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
What I have always most admired in the mole is its _eyes_. This
animal occasionally visiting the surface, and wanting, for its
safety and direction, to be informed when it does so, or when it
approaches it, a perception of light was necessary. I do not know
that the clearness of sight depends at all upon the size of the
organ. What is gained by the largeness or prominence of the globe
of the eye, is width in the field of vision. Such a capacity would
be of no use to an animal which was to seek its food in the dark.
The mole did not want to look about it; nor would a large advanced
eye have been easily defended from the annoyance to which the life
of the animal must constantly expose it. How indeed was the mole,
working its way under ground, to guard its eyes at all? In order
to meet this difficulty, the eyes are made scarcely larger than
the head of a corking-pin; and these minute globules are sunk so
deeply in the skull, and lie so sheltered within the velvet of
its covering, as that any contraction of what may be called the
eyebrows, not only closes up the apertures which lead to the eyes,
but presents a cushion, as it were, to any sharp or protruding
substance which might push against them. This aperture, even in
its ordinary state, is like a pin-hole in a piece of velvet,
scarcely pervious to loose particles of earth.--_Paley._
[Illustration: Fig. 70.--ELEPHANTS DRINKING.]
1076. _Why has the elephant a short unbending neck?_
Because the elephant's head is so heavy, that it could not have been
supported at the end of a long neck (or lever), without _a provision of
immense muscular power_.
[Verse: "Be not afraid, ye beasts of the field: for the pastures of
the wilderness do spring, for the tree beareth her fruit, the fig-tree
and the vine do yield their strength."--JOEL II.]
1077. _Why has the elephant a trunk?_
The trunk of an elephant _serves as a substitute for a neck_, enabling
the animal to crop the branches of trees, or to raise water from the
stream.
1078. _Why do the hind legs of elephants bend forward?_
Because the weight of the animal is so great, that when it lay down it
would _rise with great difficulty_, if its legs bent outward, as do the
legs of other animals. Being bent _under the body_, they have a greater
power of pushing directly upward, when the powerful muscles of the
thighs straighten them.