New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-03-29

The Young shark is favored at his birth with what
seems 70 be an egg 1t is however, bag OF nourish-
ment supplied by the maternal parent which keeps BIN
in food until he is able 10 set in business for himself
What now, would ask is the significance OF an egg
IL the egg itself an individual Is 1t being
think as We 90 shall be brought 10 the conclusion
that the is the new being, endowed with an lndyld
ualty, that is with typical character 80 dstlnct tt
never the world began did the OF any one an
mal produce an animal differing from the parent IN
essential features or the seed any plant produce
anything differing essentially from the plant which bore
IL. Whatever phases an egg passes through, however
much il transienty resembles the adult condition Of
some animal than itself in the type, IT never
ends by producing anything but the kind OF animal from
which it There Is not a solitary Instance on
record Of from that overcoming cycle Of
development which shows succession OF specihcaly
identical individuals the result OF reproduction,
whether through eggs budding division. There are
other modes of multiplication known;
one SINGLE being The egg OF the Natca, for instance
often divides 10 form several individuals though II may
also develop being In many Instances, how
ever, the Naca egg beginning one yelk, breaks up
into two four, or more one primitive individuality thus
dividing and transmuting ls pecunsIlues 10 genera
ton numerous than ITSELF This is not the case
when double birth takes place in higher animals in The
mammalla for instance Edch individual Is III that
instance the growth of separate egg. So in monstrOs
ties in the quadrupeds, where double heads and the
like abnormal developments occur they come
form the merging OF the eggs together The multiplying
Of individuals IN one egg seems more IKE the process OF
reproduction by Subdivision, in hydrolds and worms
only in the latter is kind OF reconstruction OF lost
parts. while in the former 1t Is the primitive egg growing
several beings The examine these various
processes of multiplication among animals the more
kind the fxedness OF features the world, is
that is the conclusion TO which all my studies IN
embryology nave brought me.
EGGS OF -FOUR YEARS GROWTH.
The reproduction Of individuals does not go
stantly 1t is periodical and this perodicity varies iu
different animals. Some ANIMALS require long develop
ment of themselves before they produce eggs Others
lay eggs very early in life Fowls begin to lay the first
year after their BIRTH Fresh turtles do not
young before their tenth eleventh year, sometimes
t their twelfth. In our common black and yellow
dotted fresh water terrapin in the painted eFrapln
the eggs require four years OF growth before they
are laid. Take seyenyearold turtle OF this
OF uniform size. An eight-yeaT-old turtle OF the
same kind will have two sets OF eggs one larger, one
smaller One of nine will have three SETS the old
est set being the size OF small pea turtle Of ten
years will have four sets Of and in year
win lay for the first time and give birth TO the
ture get. Other animals require but few weeks TO
bring their to full maturity In common jelly
fishes for instance with rOsecoored Ovares the eggs
begin in May. In July they all laid and the young
begin their independent life The OF laying differs
greatly IN different ANIMALS Some lay their IN
Spring, others in midsummer others, the trout fam
lily, salmon. and the like, in Autumn
feature Of this problem OF reproduction. IL would
that kinds Of ANIMALS require far greater number
Of individuals for Nthe maintenance OF the type than
others. Some animals multiply by hundreds OF thou
sands-nay, by millions. Others bring forth single
being, or at the most two or three 1T time. Some
animals bear but and then die Others,
tenacious Of life, bring forth new broods for long
period OF years. These various conditions OF growth,
duration. and ripenDg, these extraordinary differ
in the power of multiplication and reproduction,
are doubt necessary part of the economy of the
whole animal kingdom. There is nothing variable
capricous about IT, and we must not forget that who
would account Tor the origin successive introduc
tion of the different types OF organized beings which
have followed one another upon earth must include 10
his explanation the whole scheme by which character
isucs are continued ana transmitted
Before closing, and az preparation for my next
lecture will show You what the ovarian egg. DRAW
ing the blackDoaTd) IL Is microscopic IN many
ANIMALS but whatever It's SIZE 1t consists OF an outer
bag filled with a semi.transparent mud which Is some
what oily. and inner bag also filled with transpar
ent fluid which is chiefly alDuminOus. The difference
in the character OF the two fluids gives greater trans
lucenee that which nils the inner Within the
bag there spot dot, sometimes several Of
them, more less distinct. In this condition all
the eggs have shown you all eggs born of whatever
living creature, are alike