New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-04-05

to, number of vertehrates known is 5000 not to speas
Of thehos,s ario,ates mcllnsks aud ruiaIes Of
our IDEAS % the orgin and growth oi tho egE'
DEsCRrrloN oP nR EGG or THE mAhNA'A'
With this preface let us now consider the ovarian esk
"a we know 1t in mammalia, and then procceu ~
pare II with the OVARIAN cog ~ far asst ~ known ~
classes of vertebrates. When it has acquired US
growth prior to the formation OF the germ, W" ese "
tbe map,malia presents bag the walls Of when aIo
exceedingly transparent THIS bag ia uieu Wiz hioh ~,
stance which is itself transparent ana yer wor ~,
neaTs under very high magnifying power; 70
he granular, IA II dotted WIN ,n1 H. another
ing i'm the huid. In that outer Dag - mio.no, ,
diIninntiye bag containing also Transparent
1md This inner bag occupies an eocen,.iU PosuuV1n
with reference 30 the periphery OF the out pas ana IN
~ @ ono or several dots. These parts OF the
mature egg have received names lac OuteI 1Nciopos
nied the vitene membrane because t Has been ascer
tsined by comparison corresponds exactly 70 the
exceedingly thin skin inclosing tho ysih n tue men
Ss bss contains the yeik and however transparent
this fuid may be II retains the name OF yeiR 10 the
,iar substance conta med in the birds egg OF yell
ioWfsh color The yelk may be any substance which Is
contained in the outer envelope OF the egg The inner
nag is called tho eermnative yesioe. That name was
given To il under the impression that from II the germ
arises That namo has been retained though wish at
tbe ontset that you shoud free yourself from the idea
that special connection WITH the formation OF
the new being The dot or dots within the gerninatve
vcsre are ordinarily called the germinatiye dot From
their those parts have also had some other
names applied to th0m 1t Prof Purldnje OF Bres
Ian who discovered the germnative yesce, and in bis
homer some psychologists call II the Purkiniean
brane veSioe. Prof. Wagner of GOttingen discov-
cred the presence OF tho dot in the germnatye vesce
and in his honor 1t is occasionally called tho "agherah
dot or dots.
The dimensions Of such mammalian egg are very
small IL comes Just within the range Of the power oil
the human eye Practced embryolOgists may detect,
without the of the lens egg in its organ
when it has reached maturity Owing to the difference
in the power of human vision, some observers Will easily
detect the egg in its natural position in the Ovary Win
the nakedeye while Others are unable 20 see IL except
by the and the magni6sr Place the ovary under the
MICROSCOPE
various dimensions in various stages OF CROWN. IN
the germinatye dot exists; in others IL IL not yet
formed indeed vescles are found 10 the oYay III when
neither germinatve dot germnative vcscle exists
and which supposed to he eggs IN process oil iors
ton. . .
ORDER OF CHANGES IN THE EMBRYONIC ECO.
1t IA lust hero that our observations lack cont
nuity Is the vitene membrane formed first, and next
the germinatve yescle, ana last the germinatiye
dot Or, "a some observers suppose does the
formation OF the germnative vesce precede the accu
mutation transparent substance around It, this trans
parent substance becoming incOsed lastly in the outer
wall Of tina perfect egg. the socaled yeline membrane
Twill nj opinion rs 10 the priority
of these different phases but simply give you the facts
Evidently the truth is not easy 10 ascertain FOR when
you place the Ovary under the microscope the process OF
lie and consequently OF growth, is stopped The egg is
dead You see only the point Of development at which
you have arrested It, Whatever preceded the condition
of the egg of the mammal have described IT, that Is,
when the outer membrane the gcrminatve yeslce, and
the germinaye dot are formed, lot me say that Wltn
of changes which end in the formation Of the germ
This process has been carefully studied III all
It's phases, first by Carl Ernst Won Bder. the
great embryOlogis who is next TO his master, Dokln-
ger founder OF this science and after hun ana 10
greater extent with much greater nnuteness the MAN
mal egg has been watched by Prof BschOf of Munich.
who has traced all the phases OF growth Ill ING RABBIT
dog guinea pig and deer. These four are the Only
mammals Of which have complete elDbryolOglcal
history. Thus the range Of our observation Is small
But tile amount OF gathered and recorded III the
works OF BsGhoh have made him one OF the masters OF
the science and really he who has laid the fOunda-
ton OF our knowledge OF the embryOiOgy of the mann
mala, though the investigations OF Dr. Martin barry
ought not 20 be forgotten.
Twill not aude 10 those changes which take place
after the egg completed its growth but limit myself
10 "A comparison of the egg in different animals. III we
pass now bird, ind in the Ovary eggs which
can he distinguished from those observed IN
the Ovary of the mammal, only find in the former
much larger number Besides those very small ovarian
eggs larger ones-eggs rising 10 dimensions SO
considerable that they not only Visible 10 the
naked eye but may be handled with facility. mature
egg the OYary OF the hen Is about the dimension OF
small walnut IL has no she'll no white; but II Is DnlK
of yelk inclosed in a vIteine membrane, containing
geTunative vescle with germndtlYe dots Inc amOuht
Of yek is very great. If examine the yek We nhd
that It's whole substance is made up of cells This TACT at
once suggests further inquiry as 10 the cOnsutu.
non OF the iu!d contained III the yltelllne egg OF
the mammalia. The question would be answered diner
emily by different Investigators. But unqueStOnaDly The
mature ovarian egg the bird differs from that OF the
mammal in the larger amount OF yelk II contains ana Ill
the whole Of Yek consists In tne ac-
emulation of cells such numbers that they are
counted myriads These cells may be traced under
the microscope. In absence OF well drawn mems egg
give mature ovarian egg OF the swapping turtle.
which may for this purpose
OVARIAN EGG OF TURTLE. MAGSRIRD 5'5 DIAMETEks.