PROFITABLE EGG FARMING. 
occurrence therefore denotes a serious state of 
affairs, and should be met at once by depletic 
medicines, or it will probably be followed by the 
loss of the bird. 
Let us now consider the egg itself, which is a 
much more complicated organism than many 
people are aware of. There is much even in the 
shell to excite our interest. It is composed 
chiefly of prismatic particles, so arranged as to 
leave pores or interspaces between them. As 
laid, the shell is of enormous strength, so that 
it will resist great pressure between the palms 
of the hands applied to the opposite ends; 
though it is not correct that, as we have seen 
stated, “the strongest man cannot break it” in 
this way. Still, for its thickness and texture, 
its strength is phenomenal. As hatching pro¬ 
ceeds, however, the carbonic acid and dioxide 
formed by the breathing of the chick, dissolved 
in fluid, gradually dissolve a portion of the 
material, and thus the prismatic bodies are slow¬ 
ly softened and disintegrated. The shell thus 
becomes far softer and more brittle as hatch¬ 
ing approaches; and so great is the difference, 
that if the edge of a fracture made across 
a fresh egg-shell, and another of one hatched or 
hatching, be examined under a microscope, it 
will be instantly seen that the two are in a quite 
different molecular condition. Were it not for 
this beautiful provision of nature, the chick 
could never break the shell. 
The outer and inner shell membranes M and 
M, separating at the air chamber A, need no 
further explanation. Proceeding inwards, we 
come next to the white or albumen W. This 
is composed of a denser, and a more fluid kind, 
arranged in layers, which can be peeled off in a 
hard-boiled egg, like the layers of an onion. A 
layer of the more fluid kind is always next the 
shell, and another thin one, F, next the yolk, 
but enveloped by another layer, D, of the dense 
kind. If an egg be broken into a basin, there 
will further be observed attached to two oppo¬ 
site sides of the yolk, two slightly opaque and 
rather twisted thick cords C H, of still denser al¬ 
bumen, termed the chalazce. They are not at¬ 
tached to the shell, but to opposite sides of the 
dense layer of albumen, D, which envelopes the 
inner fluid layer and the yolk. They are at¬ 
tached at opposite sides, rather below the center, 
thus they act as balancing weights, keeping the 
side of the yolk which carries the germ always 
uppermost, and very nearly in floating equilib¬ 
rium. If the egg be turned round, therefore, the 
yolk itself does not turn with it, but retains its 
position with the germ on the upper side. 
It will be seen how elaborately and beautifully 
the yolk, bearing upon its upper surface the 
tender germ, is protected within the egg. Itself 
rather lighter at the upper part, it is further 
balanced by the chalazce, so as to float germ up¬ 
permost in the albumen. It is usually very 
slightly lighter than the albumen, but scarcely 
perceptibly so; thus it floats near the upper 
side of the shell, but always separated from it by 
a layer of albumen of more or less thickness, 
and oscillating gently away .from the shell on the 
least motion. In a few cases it probably floats 
more strongly up against the shell, and these are 
generally the cases in which adherence takes 
place, or the yolk is ruptured during hatching; 
but an exquisitely delicate floating balance is 
the rule. Nevertheless, it will be readily under¬ 
stood why it is inadvisable to leave an egg lying 
on the same side for any length of time. The 
shell being porous, and permitting of evaporation, 
such a course keeps the germ close to the portion 
of albumen which is slowly drying up, and 
may cause a tendency to adhesion. 
Turning now to the yolk, this is contained in a 
very delicate vitelline membrane, V. It is com¬ 
posed of both white and yellow cells, and if an 
egg be boiled hard, and cut across, it can be seen 
that there is a flask-shaped nucleus or center of 
white yolk, W Y, round which are several con¬ 
centric layers of yellow yolk, Y A". Under the 
microscope additional thin layers of white yolk 
cells can be distinguished amongst the yellow 
layers. On the top of the white yolk rests the 
blastoderm (germ skin), a small disc about one- 
eighth of an inch across, shown at B L. The dif¬ 
ference between a fertilized and an unfertilized 
egg is solely to be found in this small disc. 
10 
