New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-04-26


phsses-eegs 40 small as to DO hardly percoptlbe with
tho naked eye others largo as pins head others
the OF pea others about the dimensions OF ahaze
nut; others as large walnut. and nnay one CON-
pete mature egg. The first Of these hons had not yet
begun laying while The second already sitting upon
eggs nv tding OF these oyares the right condition
was mere chance; and. Indeed when g YOU ~,
how many fortunate circumstances are essentldl 10
sGeeessin Investigation 10 eDryo,qgy a n 9now @ liz
tie Indeed nothing better reetes tendency to over
hasty conclusions than III attempt " observe tt
DISTINCTIONS BETWEEN EGGS.
Let us now return 10 this subject where W. left u
the last lecture and consider especially the peooss OF
reproduction In yertebrates. choose that type because
vertebraes have no other mode of multiplying than by
eggs. and wish especially 10 dwell upon the his
tory OF the egg, and its Importance such in the prob
lem OF reproduction should rcc1r ffst to statement
since, which fear you may mlsnndcrotmd. state
ment made in full kiowledgo Of the facts sometimes
makes as have said, false impression upon the MINI
which receives it without any previous preparation
told you that all eggs were alike up to certain POM IN
characteristics OF al eggs in their ncpen condition
are the same. Bat toe ye2ks vi dlherent eggs
Color and she. The yeik may be- light, almost
white in sOne dark yellow. orange or reddish, green
ish or brown In others. I have the SIZE OF mems
yelk Just ready to drop into the oyiduct such as yon
have seen In the specimen Just passing or ~ may De 80
small escape the unaded vision but the elements
composing the yelk and the membrane sufrOuidlnB ~
are the in alat least no power OF the microscope
has ever yet revealed any difference III tnese paIts
Yet no naturalist would confound the egg or mammal
with that any other vertebrate The yltellne mem
70 the size OF the egg than the membrane surrounding
tho hens yek In examination ~ 10 ionDd 10 0e V9J
complex apparatus. The mammalian egg mas, lnueed
kind OF membraR0us shell, called by naturalsIs lIe
chOriOn, etIueida IL Is made or special cells
and mi ght a first be taken for part Of the yelk mem
brane and thus lead TO the impression that the Tten
membrane Of mammaha - mscn .ncner H. t,I or
birds There is also great dnerence IN te teuaciy VI
elasticity OF the yelk. The yelk oil mems egg Is 80
plastic that can press Win my ns e b sp a.ch and
others soft they can barely De nandlea. Egss a.
greatly in transparency at different periods OF the u
velopment. hens egg IS at hfst go t pco me,
the whole interior may be seen under the enOScOpo'
yellow and OPAQUE The different parts OF an egg may
differ WITH reference 70 one another Inc gerunatiso
the side IL may even be drawn so near tue ytellnc
membrane as to touch It. THIS is especially tne case
when speak OF the identity Of egg structure alude 10
the correspondence Of essential parts 0yerookhg ose
and OF no value with to the part played Ny inc
egg Ia the economy OF reproduction.
TIE FECUSDArIoS or THE EGG.
In what now does formulation consist and what IS the
substance whose with the egg contributes TO the
formation OF the new beingi When entering upon this
subject let US not get that some eggs undergo all the
necessary phases OF growth without any such influence
from the male organism and that this occurs even
among animals whose structure Us hgny t @ 49,
as wiih the bees, among whom unieeundated eggs pro
duce males or dronea while formulated eggs produce
females or working bees. Among yertebrates no egg
has ever with certainly been known To produce new
being without Foundations but In numerous cases tue
90
OF the new being as Tor instance, ~
previous fecundatOn The spermarles are organs Oh
snerm1ry cells are formed which may be com
pared to those peculiar cens VI se s I'm
% WIZ do not produce yek but gave rise within them
selves to peculiarly constructed particles usuhiy
snarmatr Dartcles Previous 10 the formation OF these
PARTICLES a kind OF augmentation OF the substance nnB
the cell takes place. which may pc eoparGa 70 te
nrocess ends In forming bundles OF hte bodies tue so
called spermary partices) which, on closer examination
auH have
them not iuaptly. They ale long IN comparison 10 ne
width almost nreadhke and have blunt ehd Win :
tsIIke appendage. When highly magnihed the cage OF
this taike appendage seems yer! lLn Suu resembles
fin when tue cell breaks which occurs under some
particles move with astounding rapldlty producing
| commotiOn in the liquid in which they are hed' ana
| having every appearance OF animated beings. III
! deed, when tDese phenomena were first Oh
| served by microscopes OF the liza century,
the spermatc particles were supposed TO
be little animals what they arc, and the part they play
in the process Of formulation, has been learned only
within few years. If indeed We know even now what
their function truly IS That they exist nFonSnout inc
animal kingdom IS an ascertaned fact ana they can DC
/ power A magnfer OF a few hundred diameers Will
bring most them, though not ALL into view, and Will
better compared than with those of the adpoe the cef
movement being wrgglng, rapid vibration Of Ire tan
times current respecting these PARTICLES Dut IL IS
useless recall them, since they have be IN found 10 Dc
| wholly incorrect At one time pbysiO gists dd not
doubt that these particles were actually the beginning
OF the germ they went so far as to assume that
they constituted the portion Of the body known as the
axis the backbone or nervous center We are sure now
tnat all these theories were nsoIha bnt Saao
! part In the economy OF rePIoaucuOh' S slnGe
Character they have been reach the egg and
penetrate into its interior TGis Is an accepted fact
though all embryOlOgists who admit 10 as sch nave
had the good fortune TO see 1t themselves
INVESTIGATIONS PRESENTING GREAT DIFFICULTIES.
When you bring egg (he spawn OF fish is perhaps
the easiest subject for the investigation into contact
with the of the sperm cells, that is, with
spermac particles, you will see these particles crowd
ing with their quick sudden movements around the egg
and covering its surface AT particular Of the
year in some OF the hermaphrodite molusks, these
particles may be seen in numbers around the eggs IL
than 70 trace their functions. The great movabity Of
the particles however, and the difficulty OF keeping any
one of them in the focus of the microscope makes the
operation an exceedingly delicate one The crowding OF
the particles about the egg OF variety OF animals Is
indeed easily in fishes, in the mousks mentioned
above and also in sea uchns and star shesand even
in Jelly fishes. IL is more difficult TO observe III the
higher animals and among insects and crustacea.
Although the introduction OF the spermatic particle
into the yelk Is so difficult OF observation there are in
yestgators who have this phenomenon repeatedly.
siebold master among masters and an observer who
never eTagSerates his facts has seen the spermate
particles Within the yelk membrane OF the bees egg
more than 20 times and mas been able to show this to
eggs of turtles and have never succeeded But my own
failure does not 10 the least diminish my confidence In
sebolds results. His capacity for observation Is SO
admirable his results free from exaggeraton
personal bias, that his statements may be accepted
I without question, To his demonstration we owe our
Hrst absolute knowledge OF this phenomenon; and in
some animals the spermac particles penetrate into the
yek more easily than in others owing to the openings
In the envelopes Of the yekthe sOcalled micropye-
through which the introduction takes place. But I'M
der any circumstances these micropyles" difficult
TO watch So experienced an observer as Bisch0, at
the time he published his magnificent embryologieal
monographs on maInmaa had never had the good for
tune to see spermac particle penetrate ntoa mammal
| egg, or to detect within the egg, He indeed,
doubted aud conroverted the fact until Ii was demon
strated past oil question. The nature OF the special in
| fuence exercised by the spermatic particles In
! the growth of the egg is not yet ascertained;
but this much at least we know with certainty viz:
that the sperlatc particles penetrate into the yek and
that combination thus taking place between
the substance OF the spcrmac cells and the substance OF