QUALITY IN EGGS 
infertile eggs, as the germ of the chick is microscopic in size. 
If the egg is immediately cooled and held at a temperature 
below 70 degrees, the germ will not develop. At a tempera- 
ture of 103 degrees, the development of the chick proceeds 
most rapidly. At this temperature the development is about 
as follows: 
Twelve hours incubation: When broken in a saucer, the 
germ spot, visible upon all eggs, seems somewhat enlarged. 
Looked at with a candle such an egg cannot be distinguished 
from a fresh egg. 
Twenty-four hours: The germ spot mottled and about the 
size of a dime. This egg, if not too dark shelled, can readily 
be detected with the candle, the germ spot causing the yolk 
to appear considerably darker than the yolk of a fresh egg. 
Such an egg is called a heavy egg or a floater. 
Forty-eight hours: By this time the opaque white mem- 
brane, which surrounds the germ, has spread well over the 
top of the yolk, and the egg is quite dark or heavy before the 
light. Blood appears at about this period, but is difficult of 
detection by the candler, unless the germ dies and the blood 
ring sticks to the membrane of the egg. 
Three days: The blood ring is the prominent feature and is 
as large as a nickel. The yolk behind the membrane has be- 
come watery. 
Four days: The body of the chick becomes readily visible, 
and prominent radiating blood vessels are seen. The yolk is 
half covered with a water containing membrane. : 
These stages develop as given, occuring at a temperature 
of 103 degrees. As the temperature is lowered the rate of 
chick development is retarded, but at any temperature above 
70, this development will proceed far enough to cause serious 
injury to the quality of the eggs. 
For commercial use eggs may be grouped in regard to 
heating as follows: 
(1) No heat shown. Cannot be told at the candle from 
fresh eggs. 
(2) Light floats. First grade that can be separated by 
candling, corresponding to about twenty-four hours of incuba- 
tion. These are not objectionable to the average housewife. 
(3) Heavy floats. This group has no distinction from the 
former, except an exaggeration of the same feature. These 
eggs are objectionable to the fastidious housewife, because of 
the appearing of the white and scummy looking allantois on 
the yolk. 
(4) Blood rings. Eggs in which blood has developed, ex- 
tending to the period when the chick becomes visible. 
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