HOW TO CANDLE EGGS. 
IS 
can be used as a working guide in the candling of eggs. The terms 
used to express the specific condition of the eggs are defined in the 
general description of shell, white, and yolk, as discussed on pages 
6 to 12. 
FRESH EGG. 1 
(Plates I and II.) 
BEFORE THE CANDLE. 
Air space: Not enlarged; less than 
three-fourths inch in diameter. 
White: Firm and clear. 
Yolk: Dimly seen through the white 
as a shadowy object indistinct in 
outline. The chick spot is not 
visible. 
Distinguishing characteristics: No 
shrinkage and general firm condi- 
tions of white and yolk. 
OUT OF THE SHELL. 
Edible. 
White: Firm and thick; opalescent; 
reflects the light. 
Yolk: Spherical and firm; chick spot 
small with no sign of hatching. 
Color is uniform for the entire yolk, 
but varies in color from light yellow 
to deep orange, and is occasionally 
olive green. 
Distinguishing characteristics: 
General firm condition of white and 
yolk. White, opalescent. 
HATCH-SPOT EGG. 
(Plate III.) 
BEFORE THE CANDLE. 
Air space: Usually enlarged. 
White: Thin and clear. 
Yolk: A distinct reddish glow around 
the germinal spot, which is visible ; 
usually located above the middle of 
the egg. 
Distinguishing characteristic : Red- 
dish glow on the yolk. 
OUT OF THE SHELL. 
White: Thin and clear; no opales- 
cence; does not reflect the light as 
strongly as does a fresh egg. 
Yolk: Bears a hatch spot; is flattened, 
being especially weak around the 
embryo. 
D is tingu ishing characteristic: 
Hatch spot on the yolk. 
Edible. 
Occurrence: Chiefly durin; 
warm weather or hatching season. 
STALE EGG. 2 
BEFORE THE CANDLE. 
Air space: Enlarged ; the lower wall 
may be movable in outline. 
White: Thin and clear. 
Yolk: Definite in outline; sometimes 
weak, and may occasionally have 
dark, mottled areas. 
Distinguishing characteristics : En- 
larged air cell and increased contrast 
between white and yolk as compared 
with a fresh egg. 
Edible. 
Occurrence: Among eggs not marketed promptly 
OUT OF THE SHELL. 
White: Thin; no opalescence; does not 
reflect the light as much as does a 
fresh egg. 
Yolk: Flattened, and occasionally may 
have light, mottled areas. 
D is Unguis hing characteristics: 
Thin white and flattened yolk. 
!The color of a white egg before the candle is yellow with a pinkish tinge, that of a 
brown egg is pinker, and that of a dark brown egg is almost red. In each instance the 
color deepens in the region of the yolk. 
2 Illustrated in color in TJ. S. Dept. Agr. Bui. 51, PI. IIL 
