THE POULTRY BOOK. 
21 
sustenance for supporting life in the bird herself. But another object is also served ; 
for by the contraction of the air in the air vesicle, when the hen leaves the nest, 
and the eggs are cooled, a fresh supply of air enters, which we may suppose ad- 
vantageous to the enclosed chick ; and it has been found desirable, by those who 
have employed artificial incubators, to remove the eggs from the machine during 
half an hour daily, so as to imitate, as far as possible, the natural cooling. 
It is desirable daily to examine each nest when the hen is off. An egg may be 
broken, and the fragments of the shell may dry on the others in places where the 
first efforts of the young chicks to free themselves may be attempted ; and this double 
casing proving too much for their beaks, they may eventually die in the shell. When- 
ever the nest is found in a dirty state, from this or any other cause, take a bowl of 
tepid water, and with a piece of flannel wash the eggs, gently removing any sub- 
stance that may be found adhering to them, replacing them again in the nest, 
having previously furnished it with clean straw. Do not let the temperature 
of the water exceed that of new milk, and, when perfectly dry, get the eggs 
under the hen at once, so that no chill may happen. It is unnecessary to 
add that, where this is neglected, the fetid atmosphere produced by the 
decay of the contents of the broken eggs is as injurious to the prospective 
chickens as offensive to the proprietor. In this daily inspection, count 
the eggs over, so that if by accident another hen may have gained entrance, her 
egg may be at once removed, — the originals having been duly marked in the first 
instance by making a ring with ink or pencil around their circumference, which is 
visible in every position of the egg. If from any cause the egg of a valuable fowl 
has been slightly cracked within a few days of hatching, it may be worth while to 
plaster up the fracture with a piece of paper and gum, or the edge of a postage 
stamp, as numerous instances are on record where such eggs have hatched in due 
time, and the progeny flourished. 
Our own practice is to examine the eggs at the end of a week, and remove those 
not fertile ; this is readily accomplished by taking a candle into the sitting house 
at night, and on holding the eggs near the flame, sheltering the eye at the same 
time from the direct action of the light, the sterile eggs are readily distinguished, 
being correctly described by the adjective clear, which is usually applied to them ; 
those which are fertile are at that time perfectly opaque. A little practice renders 
the distinction easy. The clear eggs being removed, more room remains for those 
that are fertile, and they receive a greater share of warmth. Those who follow 
this plan will find it advantageous to sit two hens on the same day, and if, on 
examining both nests at the expiration of a week, many sterile eggs are discovered, 
the whole of the remainder may be given to one hen, and a fresh setting placed 
under the other. 
In Cornwall, it is usual to test the eggs on the eighteenth or nineteenth day, by 
placing them in a bowl of tepid water ; those containing living chickens are in imme- 
diate motion, bobbing and reeling on the smooth surface, — for the vessel must be 
kept perfectly still. These are v/iped, and returned to the hen, the others being 
