Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1916-11-02
DWARF EGGS
Notes From the Experiment Station

Orono, Me-, Nov. 1.-(SpeciaD.-The
following was today made pubic by
Charles D. Woods, director OF the
Maine Agricultural Experiment Sta
ton at the University of Maine.
Almost everyone who has kept fowls
has found hens eggs as small or small
er than a pigeons egg. Such an egg
may be found at any time of year but
they are most common during the late
spring and early summer. These small
eggs may be soft or hard shelled and
the egg white is usually but not always
of thicker consistency than the white
Of a normal egg. Some of them con-
tain a small yolk without a germ spot
but many more contain only few
drops or a coagulated lump Of yolk. A
few have no yolk whatever.
A century or two ago there were
great many superstitions associated
with these eggs. The name derived
from the superstition once commonly
accepted in a particular region often
remains in use as the local name for
these eggs. Thus in different places
they are called cock eggs, witch
eggs, wind eggs. etc. The most
of these superstitions is the one that
such eggs are laid by cock birds. With
the passing of the age of superstition
the more descriptive term dwarf eggs"
has come into use.
1t is still commonly believed that a
dwarf egg marks the end of litter.
Since dwarf eggs are most common
during the season of year when the
birds are most apt to be broody it is
easy to understand how the two things
seem to be related. The use Of the
trap nest and Individual egg records,
however dispels the illusion. A dwarf
egg Is no more likely to be the last
than the first or any other egg in a
litter.
| When dwarf eggs were supposed to
represent the ends Of filters they were
| explained either as the residue left in
the egg tube after the series had ended
or as the secretion of the egg tube
| which remained active after the ovary
had ceased to function In face Of the
fact that the dwarf egg does not repre-
sent the end Of series these explana-
lions must be abandoned What then
is the cause for the production of. a
dwarf egg?
Eight years investigation of dwarf
egg production at the Maine Agricul-
tural Experiment Station poultry
plant has thrown considerable light on
this question. First, it has shown that
in all cases where dwarf egg was
produced there was evidence from the
egg record Of the bird, checked in sew
eral cases by immediate post mortem
q v mi ~ hot hn to,
active condition and was maturing and
discharging yolks. Second, in IS per
cent. of the cases the disturbance was
of a temporary character since the
dwarf egg was one of a series of eggs
and was preceded and followed by nor
NAL eggs exactly as though it were
itself a normal egg. Post mortem ex-
aminations of many of these cases
showed normal sex organs. Third. two
thirds Of all the dwarf eggs contained
| some yolk. In many cases post mort
eE1 examination showed that the rest
of the yolk was free in the body cav
ity IN one case a dwarf egg contain
ing some yolk was found in the shell
gland. Attached to the ovary was a
follicle containing a partly ruptured
yolk membrane from which yolk was
draining into the body cavity.
From the above facts it is clear that
at least two-thirds of all the dwarf
eggs result from the stimulation of a
normal active egg tube by a small
yolk or more often by a part of a
normal yolk, the rest of which escapes
into the BODY cavity. In all cases the
active egg tube is associated with a
fully functional ovary.
| During several post mortem exam
nations free yclk was found in the
body cavity of birds which had Just
| laid, or which still held in the, egg
tube. yolk'ess dwarf egg. Also sever
| al yclkless dwarf eggs contained one
or two apparently perfect chalazae. In
| these cases it seems possible that all
or part of yolk may have entered
| the egg tube, started the secretion of
the egg white and may then have been
| eXtruded leaving behind enough of the
| white to furish the stimulus for the
completion Of the egg. It is known
certainly that the discharge of yolk
from the ovary to the body cavity
when there is no stimulation of the egg
tube does not result in the formation of
dwarf egg or in the production of
any secretion in the egg tube. In a
single case a yolkless dwarf egg con-
tanning a small lump Of hardened egg
| white was found in an egg tube and
no yolk was found in the body cavity.
It has also been shown experimentally
that in certain cases an active egg tube
can be excited to secrete egg white
and shell around an artificial yolk
when all possibility Of the entrance of
yolk is excluded. 1t is. therefore,
probable that in a small percent of the
lilo rnlrNn ulInf.