Evening times-Republican. [volume] (Marshalltown, Iowa) 1890-1923, 1916-03-10
THE POULTRY YARD
THE STRUCTURE OF AN EGG
By ED WEBER

If hen be dissected there will be
found in each side of the backbone two
little punches of immature eggs. These
are the ovaries: one remains rudiment-
airy and the other Casually that on the
left side) VIII in time become active
and produce ripened yolks. Various
calculation have been made as to the
number of oyules in hens ovary, and
altho the usual estimate is 500. casts
are on record of hens which have laid
1000 eggs.
Roughly. the immature egg consists
Of the germ. the yolk material. and
the delicate membrane enclosing it.
These are, in the ovary. included in the
ovisac which is connected with the
Ovary by thin tube termed the pedi-
Gle. II the hen under examination Is
laying, these ovules will vary in size
from q mature yolk Of ordinary size
down 10 small ones whose size can not
be gagged by the unaided eye. AS soon
as the yolk is ripe, or matured, and
ready TO be cast off by the ovary, the
ovisac which has during distension be-
come very thin at it's greatest diameter,
bursts at line called the stigma, and
SO releases the yolk. Attached to the
hens intestnes by various processes
the oviduct. One end. that nearest the
ovary, is free, and is funnel-shaped.
The other end communicates with the
cloaca at the vent. The ovlduct varies
from eighteen inches in small fowl
to twenty-four inches in a large one.
Coincident with the rupture Of the
ovisac and the shedding of its enclosed
yolk, the free funnei-shaped end of the
oviducr arises and grasps the yoIk as it
! leaves it's sack. When first received in
! the oviduct and until 1t mas travelled
about four inches there is no addition
OF a!bumen or white, but at about that
! point secretion takes place, and seven
! Oh eight layers CT white CT eihur,en. Of
| different thicknesses and different de-
, grees Of density. are secreted by q set
! Of glands and enclose the yolk. When
| this is finished the inner skin-a very
delicate, semi-transparent membrane
is secreted and envelops both the white
! and it, Included yellow.
! 4 fresh set of glands now secretes a
| much stronger membrane, which is the
; outer skin lining the shell of the egg.
! Between theses kins, and as a rule, at
the large end of the egg, these men,
| branes separate and form the air sack.
! Farther down the oviduct the egg re-
! ceives its shell which Is secreted By
other glands. The egg she'll is COM
I posed ,of lime, salts, etc, and Is de-
posted in the form Of prisms,, the for
nation allowing for numerous pores"
or minute openings thru the walls Of
the shell. In hens which lay eggs with
tinted shells there are other glands
! which discharge a pigment which
colors the shell more or less. Shortly
after this the egg is extruded. The time
occupied in the formation and passage
OF the egg dvwn the o":a3c. &c nnde.
normal conditions about eighteen
| hours. 49, =
Abnormal Eggs.
If the ovaries' are unduly excited It
may happen that two or even three
yoiks mature and are shed simuItane-
ously. These become enveloped in the
abdomen, then in the membranes. and
finally in the shell, which is of size
proportionate to the, contents. Small
eggs containing no, Yolk and only a
little albumen are due to false stimula-
ton of the oviduct. No yoik Is shed
by the cvary but the glands in the
duct secrere quantity geneT all
small, Of albumen which Ia, enclosed in
the mebranes ami in s::. = rcss::::a s.!
sheii. rE rF 155t3s - ~ 5F3f4 ~ s :
i Eggs without shells or soft -shelIed