8 BULLETIN 565, U. S. DEPARTMENT OF AGRICULTURE. 
or in one which has been exposed to warm temperatures, as in summer 
or by incubation. The condition of the white is indicated on candling 
by the ease with which the yolk moves when the egg is rotated. For 
example, in a fresh egg the white is so firm that the yolk sways 
but little during candling, whereas in an egg with a weak white the 
yolk moves much more rapidly. A further indication of a thin white 
is seen on candling by the ease with which the white moves at the 
air cell, which usually is enlarged. Out of the shell the difference 
between a firm and a thin white is detected easily by pouring the egg 
from one dish to another. As an egg becomes stale the amount of 
thick white decreases and the amount of thin white increases. 
Out of the shell the white of the fresh egg has an opalescent 
tinge, which characteristic is lost when an egg becomes stale. Eggs 
are found sometimes in which the white is as thin as water. Such 
eggs, however, are encountered rarely in ordinary candling. They 
are detected by the exceedingly rapid motion of the yolk when 
the egg is turned before the candle and by the very watery appear- 
ance of the white at the air cell, which usually is broken. The watery 
condition is caused, in most instances, by bacteria which penetrate 
the shell when it is broken or wet and grow in the egg material, 
destroying the mechanical structure of the white. "When such eggs 
are opened the white flows out as readily as water and may be color- 
less, although usually it is a yellowish brown. The odor is bad and 
ammonia frequently is detected. Eggs with whites thus liquefied are, 
inedible. 
Several classes of bad eggs are indicated by discolored whites. Of 
these, eggs with yellow, bloody, moldy, and green whites are the most 
numerous. 
A yellow white represents one of the most common forms of egg 
deterioration and is caused by the disintegration of the yolk. The 
whites assume a clouded yellow color before the candle, the depth of 
the color depending upon the amount of yolk present. (See PI. VI.) 
Eggs with bloody whites are comparatively rare. They occur most 
frequently among pullets' eggs in spring and fall and are caused by 
rupture of blood vessels of the hen during the passage down the 
oviduct of the egg before it is covered with the shell. The blood may 
be present in the egg in the form of clots attached to the yolk or 
distributed through the white. Such eggs are detected on candling 
by the red color of the white and by the clots which appear as 
irregular-shaped bodies floating in the egg. (See PI. X.) If eggs 
with bloody whites are inclosed in white shells, the red color is 
detected easily by candling; if they are inclosed in brown shells, it 
is not so easy to distinguish between the deep pink color caused by 
the shell and the red color due to the presence of blood. An orange- 
colored yolk also may make it difficult to detect an egg with a bloody 
white. 
