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Union of the Ovum and Zoosperm.--The zoosperms not only come in contact
with the ovum, but penetrate the thin membrane which incloses its
contents, and enter its interior, where they disappear, becoming united
with its substance. In the ova of certain fishes, small openings have
been observed through which the spermatozoa find entrance. Whether such
openings exist in human ova is an undecided question; but it is probable
that they do.
Curious Modes of Reproduction.--A peculiar kind of reproduction is
observed in a variety of polyp, a curious animal which very much
resembles a shrub in appearance. It attaches itself to some solid object,
and then, as it grows, sends out little protuberances resembling buds.
Some of these separate and fall off, swimming about as separate animals.
These never become like the parent polyp; but they lay eggs, which hatch,
and become stationary polyps like their grandparent, and in their turn
throw off buds to form swimming polyps. In this case we have two kinds
of generation combined, alternating with each other.
Plant-lice afford a curious illustration of a similar generation. Males
and females unite and produce eggs. The creatures produced by the
hatching of eggs are neither males nor perfect females. They are
_imperfect females_. They are all alike, so that no sexual union occurs.
Instead of laying eggs, they produce live young like themselves, which
appear to be developed from internal buds similar to the external buds
of the polyp. After this method of reproduction has continued for eight
or ten generations, a few perfect individuals appear, and the first
process is repeated.
The common honey-bee affords another illustration like the last. A
virgin queen sometimes lays eggs, which always produce males, or drones.
After union with a male, she lays eggs in the royal cells which become
perfect females like herself. She also seems to have the power to lay,
at will, unfecundated eggs, from which drones are produced.
Human Beings Are Developed Buds.--It has been very aptly suggested by
an eminent physiologist that the ovum and zoosperm may be correctly
considered as internal buds. Thus it would appear that generation is
universally a process of budding. A child is but a compound bud, an
offshoot from its parents. This idea is not a mere fancy, but has a
scientific basis. As all the exquisite details of the most beautiful
flower are in essence contained within the tiny bud which first makes
its appearance, so is the developed human being, the full-grown man
or woman, virtually contained within the tiny cell called the ovum after
it has been impregnated or fecundated by the zoosperms. In short, men
and women are blossoms in a strictly scientific sense.
Fecundation in Hermaphrodites.--The process of fecundation in
hermaphrodite animals is very peculiar. In some cases, as in the snail,
the union of two individuals is usually necessary, though each
possesses both kinds of organs. In other cases, as in the tape-worm,
the oyster, and numerous other mollusks, a single individual has the
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