The Daily Missoulian. [volume] (Missoula, Mont.) 1904-1961, 1917-11-04

II is doubtful il there is a more in
tercsting story in any branch Of physi-
ology than the development Of an egg.
The problem OF determining: the best
way to feed and care for hens to in
duce heavy egg production receives
hours of study. TO distinguish the
hens capable Of laying the greatest
number of eggs in a year, laying con-
tests are conducted under government
supervision. These hens have the
most favorable environment for pro-
ducing eggs; they are furnished with
choice foods selected according to the
latest feeding standards. but our over
sight and regulation cease when we
allow the hen every facility to lay.
Each hen controls. either efficiently or
otherwise. the inside machinery that
turns out the finished product in the
shell.
1t is natural and correct to suppose
that the yoll Of the egg is made first.
Attached to the body cavity of the hen
near the left kidney are organs called
the ovares which develop yolks as de-
| sired In birds the left ovary alone
functions, the right degenerating at an
| early age. This is doubtless due to the
| large size of the egg and the delicate
nature Of the shell, there not being
| room for two eggs side by side in the
lower part of'the body cavity.
The yolk first appears as a minute
cell on the surface of the ovary. BY
examining this organ with n micro
scope as many rs thirteen thousand
| ynlli cells have been seen, so that there
is no possibility of the ovary running
short of cells during the life of the hen.
The growth OF each yolk from the mi
mute cell to normal size is constant
during the laying period Moreover, as
there are yolks in all stages of devel-
opment to maintain the daily produce
ton of eggs, the ovary at this time
presents somewhat the appearance of a
| bunch Of grapes. Each yolk is attached
TO the ovary by Il thin sac. which Is
ruptured when the yolk attains its
| normal size.
AS the yolli bursts its sac and
escapes from the ovary, it is swallowed
in the wide. funnel shaped mouth OF
the second organ of reproduction called
the oviduct. This is large, coiled
tube about twenty inches long, whose
| function it is to sccrcte sufficient al
bumen (whitc of cgg) to form the egg
and to inclose it with two membranes
or skins.
Real Egg Size Of Pea.
The true egg of the hen is not the
large. shelled egg we know so well. II
is small light -colored disc. not larger
than n pea, which floats on the upper
surface of the yolk. Before the germ
can grow into a chick during the proc
ess of incubation, it must be fertiiiZed
by a sperm cell. otherwise the egg Is
known as infertile or sterile.
The small germ must obtain all the
prot"plasm or material to form the
body and feathers of the chick, and
for its nutrition during the three
weeks Matching period from inside the
egg. Hence. there is II large amount of
lalbumen surrounding the germ, which
il converted into the body and feathers
of the chick. and a supply of yolk for
its nourishmcn,
Since the yok is mainly fat or oil
and the albumen principally water, il
| would be natural for the oily yolR to
float at the top Of the watery albumcn
But this position of the ynlk would
cause the germ to lie against the side
of the egg. where it would be imros
sible for the egg to hatch Therefore
nature has suspended the yolk by two
twisted cords inside cushion of dense
alhumen at the center of the egg. This
method of suspension absolutely pre-
vents the yolk of a fresh egg moving
from n central position. while the
spring in the twisted cords overcomes
any sudden jar that would otherwise
rupture the yolk.
The yolk or egg revolves on it's axis
as it is slowly forced through the owl.
duct by the peculiar wormlke contrac.
tons OF that organ. Layer upon layer
of albumen is constantly added, at frs
| quite dense, then thinner and final,
when the process is about complete,
almost watery in its composition. Tn,
secretion of albumen is estimated I,
occupy about three hours.
), Formation Of Shell Membranes.
When about two-thirds the length o
the oviduct is traversed and the secre
ton of albnmen is almost over, the eg,