Liberal Republican. [volume] (Dallas, Or.) 1872-1???, 1873-05-17
THE WONDERsOF THE EGG.

| In the raolates, the lowest type OF
the animal kingdom, the eggs are most
ly microscopic. / shall have more to
say Of them hereafter, and of other
modes of reproduction common to this
type. Before entering upon this part
of my subject wish to make a broad
experimental statement about all eggs
and all animals. These eggs, whether
of vertebrate, artlculate, mollusk, or
radiate, appear at some time or other to
be Identical in structure, At least, no
investigator has ever been able to de-
tect any essential difference in them.
They are all formed in an organ be-
longing to the maternal being,
known as the ovary. In some animals
this organ is very simple. Whatever
its structure, however,whether complex
or simple, there is spot in the female
organism known as the ovary, in which
eggs are formed, from which new
beings may be developed. But before
the egg develops into the new bsing, it
must be formulated For what have
said thus far with reference to absolute
identity of egg structure througout
the animal kingdom refers only to the
egg as egg, before the process OF fe-
cundation takes place. There IL an
organ in the male organisms, cores
ponding to the ovary in the female
organisms; iu which spern cells are
! formed, the contact Of the contents Of
Shich with an ovarian egg is an
indispensable condition for the growth
of new being. There are no animals
known in which these corresponding
organs do not exist
Reproduction in the Vegetable kingdom
is based on similar structures with sim
| liar relations TO one another. These
two conditions, essential to the main
tenance of types, shonld be we'll
weighed by any one who would ap-
proach the problem Of the origin of
life.
Before showing you the structure of
the egg prop,r, as it exists in all ami
rlals before it takes upon itself any
individual character, | will say word
on other modes of reproduction, 10
order that you may have before you
the whole subject, aud that ] may not
be limited in my comparison to the
ovarian eggs and fer,ilizing cella, but
be able to include budding and self
division among the reproductive pro-
cesses.
With ra liates, es,ecia ly among the
hydroids, multiplication by buds and
by self division il common. An indi-
vidual such as | sketch on the board
(tydroid), puts out bud from the
main trunk. This bud grows into an
individual similar to the parent, and it
gives rise In its turn to q number Of
buds which go on multiplying in the
same way till large community is
formed. Ia other instances su.h buds
may drop off, and become free. indi-
viduals. Sometimes again, new indi'
vidlals arising IN this way differ from
the parent, aud only in their offspring
reproduce being resembling
the one from which they sprang.
Many hydroids, aud even some of the
acaleps, multiply by a still more simple
process-that of self division. The
primitive stock bresks up transversly at
regular intervals by construction, aud
each such part, when thrown of,
becomes q new individual, while the
parent remains unimpaired in its vitali-
ty.
Certain worms, also, multiply in
this way, dividing into parts, and each
! part building itself up into new and
perfect being. Instances are also
known Of longitudinal division leading
to the same result. Not only 10 it true
that there are other modes of reproduce
ton besides that of eggs, but it is also o
fact that the sntagonism between male
and females ,on which the whole processes
of multiplication and increase among
animals seems to rest, j. not always
necessary for the production Of new
individual.