1286. _Why are the seeds of plants indigestible?_
Because they are encased in a hard covering upon which the gastric
juice of animals takes no effect. This provision has been made by the
Creator, _for the preservation of seeds_, the productions of which are
so essential to animal life.
The gastric juice can dissolve any other part of the plant, even the
woody fibre, and yet upon the _seed_ it takes no effect. When, however,
the seed is _crushed_, and, thereby, the vital principle destroyed, so
that no plant can spring from it, the gastric juice acts upon it, and
it is soon dissolved.
Hence graminivorous birds are provided with gizzards _to break the
protecting coats of the grain_; and animals that feed on seeds and nuts
_strip them of their shells and husks_.
It is remarkable that in the _succulent fruits_, such as the
strawberry, the raspberry, currant, apple, orange, melon, &c., and
which, from their very nature, are likely to attract animals to use
them, and in eating which _the seeds are likely to be swallowed_, they
are fortified by a doubly-protective coating; the pips of the apple,
orange, &c., and the seeds of the strawberry and raspberry, pass
through the digestive organs, not only unharmed, but their germinating
powers are even improved by the warmth and trituration of the stomach.
Indeed, the stomachs of quadrupeds and birds have been made the
vehicles of propagating plants, and distributing them to the widest
geographical latitudes. It is even said of some seeds that they will
not germinate until they have passed through the digestive organs of an
animal.
[Verse: "And it was commanded them that they should not hurt
the grass of the earth, neither any green thing, neither any
tree."--REVELATION IX.]
1287. _Why do animals that graze, crop the tender blades of grass, but
avoid the tall stems?_
Because they are tempted by the greater sweetness and tenderness of the
young blades; and in this temptation a very important end is served;
for, by avoiding the stems that have grown up, _the animals spare the
matured plant by which seeds are borne_, and by which the supply of
food is to be continued.
1288. _Why do the eggs of butterflies lie dormant during the winter?_
Because the _coldness of the winter_ would be fatal to the life of
the young insects; and the absence of vegetation would leave the
caterpillars to _perish of starvation_, if they were developed during
the winter months.
[Illustration: Fig. 76.--CATERPILLAR FEEDING.]
1289. _Why do caterpillars appear in the spring?_
Because the increasing warmth of the sun developes the living embryo,
_at the same time that it developes the vegetable germ_. The warmth,
therefore, that calls the caterpillar from its embryo sleep, also
kindles the germinating power of the vegetable upon which it is
destined to feed. The worm awakes and finds the bountiful table of
nature spread for it.
[Verse: "Thou shalt plant vineyards, and dress them, but shalt
neither drink of the wine, nor gather the grapes: for the worms shall
eat them."--DEUTERONOMY XXVIII.]
1290. _Why does the caterpillar eat voraciously?_
Because it _grows rapidly_, and a large amount of vegetable matter
is necessary to supply the rapid growth of its animal substance.
Caterpillars in the course of a month devour 60,000 times their own
weight of aliment.
[Illustration: Fig. 77.--THE UNDER SIDE OF THE CHRYSALIS OF THE PEACOCK
BUTTERFLY.]
[Illustration: Fig. 78.--THE SAME CHRYSALIS, WITH PART OF ITS SHEATH
RAISED TO SHOW THE PARTIALLY-FORMED WINGS, &c.]
1291. _Why do caterpillars pass into the state of the chrysalis?_
Because they are thereby prepared for the new existence which they are
about to enjoy; _new organs must be perfected in them_ to adapt them to
the altered conditions of their lives.
Because, also, in the transformation of their bodies, differing
materially from the laws of existence that pertain to other creatures,
the Creator affords another illustration of his Omnipotence.
Because, also, during the stage that the insect sleeps in the
chrysalis, the flowers and their sweet juices, upon, which the fly is
to feed, are being prepared for it, just as, when it was sleeping in
the egg, the green food was being prepared for the caterpillar. When,
therefore, the beautiful fly spreads its silken wings, it finds a
_second time_ that, while it has slept, its meal has been prepared, and
it now flies away joyously to feed upon the milk and honey of beautiful
flowers which, at the time it passed into the chrysalis, had not yet
unfolded their petals.
[Verse: "For the moth shall eat them up like a garment, and the worm
shall eat them like wool: but my righteousness shall be for ever, and
my salvation from generation to generation."--ISAIAH LI.]
[Illustration: Fig. 79.--THE PEACOCK BUTTERFLY.]
Paley observes, that "the _metamorphosis_ of insects from grubs into
moths and flies, is an astonishing process. A hairy caterpillar
is transformed into a butterfly. Observe the change. We have four
beautiful wings where there were none before; a tubular proboscis, in
the place of a mouth with jaws and teeth; six long legs, instead of
fourteen feet. In another case, we see a white, smooth, soft worm,
turned into a black, hard, crustaceous beetle, with gauze wings. These,
as I said, are astonishing processes, and must require, as it should
seem, a proportionably artificial apparatus. The hypothesis which
appears to me most probable, is that, in the grub, there exists at
the same time three animals, one within another, all nourished by the
same digestion, and by a communicating circulation; but in different
stages of maturity. The latest discoveries made by naturalists, seem
to favour this supposition. The insect, already equipped with wings,
is descried under the membranes both of the worm and nymph. In some
species, the proboscis, the antennæ, the limbs, and wings of the fly,
have been observed to be folded up within the body of the caterpillar;
and with such nicety as to occupy a small space only under the two
first wings. This being so, the outermost animal, which, besides its
own proper character, serves as an integument to the other two, being
the farthest advanced, dies, as we suppose, and drops off first. The
second, the pupa or chrysalis, then offers itself to observation. This
also, in its turn, dies; its dead and brittle husk falls to pieces, and
makes way for the appearance of the fly or moth. Now, if this be the
case, or indeed whatever explication be adopted, we have a prospective
contrivance of the most curious kind; we have organisations _three
deep_; yet a vascular system, which supplies nutrition, growth, and
life, to all of them together."
[Verse: "That which the palmer-worm hath left hath the locust eaten;
and that which the locust hath left hath the canker-worm eaten; and
that which the canker-worm hath left hath the caterpillar eaten."--JOEL
I.]
Lord Brougham, in a note upon the above, does not support Paley's
view. He says "It is more than probable that the parts which are to
appear in the perfect insect do _not_ exist in the larvæ, where there
is not much difference between the larva and pupa, excepting at the
time just previous to its becoming a pupa, at which time the larva is
motionless and torpid. The caterpillar of a moth, when about to turn
into a pupa, provides for the protection of the latter state, either by
surrounding itself with a web, or by some other means. Soon after this
is accomplished, the caterpillar becomes motionless, or nearly so; it
can neither eat nor crawl. At this time, and _not before_, the parts of
the pupa are forming within the skin of the caterpillar, which may be
easily seen by dissection."
It appears to the author, however, that Paley is partially right, and
Lord Brougham totally wrong, in these remarks. When Lord Brougham
asserts that the parts of the pupa are forming within the skin of
the caterpillar at that time when the transformation begins, "and
not before, which may be easily seen by dissection," he forgets,
that although in some instances it is the first moment when, to the
human eye, the organs of the new creature _become perceptible_, that
the "_three deep_" nature which Paley attributes to the _grub_, must
really have existed _in the egg_--that the _butterfly_ originated _in
the egg_, as certainly as did the _caterpillar_, or the _chrysalis_,
and that unless that egg had possessed its three mysterious embryos,
it would have been impossible for the grub to have progressed to
the stages of transformation. No one has ever known the embryo of a
bird's egg to pass through three distinct and dissimilar states of
existence; nor has any one ever known the embryo of the butterfly's
egg to stop short at either of the stages, if the proper conditions of
its existence and development were supplied to it. _Why?_ Because the
embryo of the insect has a _threefold_ nature, while that of the bird
is _single_.
[Verse: "They shall cut down her forest, saith the Lord, though it
cannot be searched; because they are more than the grasshoppers, and
are innumerable."--JEREMIAH XLVI.]