HOW TO CANDLE EGGS. 



however, the contents shrink and the two membranes separate at the 

 large end of the egg, forming an air space less than three-quarters 

 of an inch in diameter. The outer or shell membrane follows the 

 outline of the shell and is both tougher and thicker than the inner 

 or egg membrane, which follows the outline of the egg contents. 



The shell of the egg is porous and varies in color from white to 

 dark brown, depending upon the breed of the hen laying it. The 

 yolk is composed mainly of fat, protein, and water; the white, of 

 protein and water. The yolk sac, shell membrane, and fibers in the 

 white are made of keratin, a material similar chemically to finger 

 nails or the horns or hoofs of animals. The shell is principally 

 carbonate of lime. 



Germinal spol. 



,Yo/k 



Thin whii& — -._ 



Air space- 

 Ch&laj-s 



■ Yolk rnemhr&ne. 



^Chala 



'J a 



Thick while, 



Thin while. 



s Off ■-■ £-<?'? niemhnsne 



Shell me,rnbr<3nes 



Sh&JI 



Fig. 4. — Structure of an egg. 

 HOW TO HOLD AN EGG WHEN CANDLING. 



The room in which the candling is done must be dark. The egg 

 is held by hand in a slanting position with the large end against 

 the opening in the candle. A few moderately rapid twists are given 

 to the right and to the left. During this turning, which should be 

 enough to expose the entire surface of the egg to view, the size of 

 the air cell and the condition of the white and yolk should be noted. 

 After this movement the egg should be turned from end to end so 

 that the whole of the egg is again seen. If the egg is not completely 

 turned before the candle bad eggs, such as those containing mold 

 spots or yolks stuck to the shell, may not be detected. In other 

 words, one side of an egg may appear good on candling, but the 

 other side may be found to be bad if brought into view. 



It is customary to pick up two eggs in each hand, supporting one 

 egg at a time in the tips of the thumb and the first two fingers (see 

 fig. 2). Each egg should be candled separately. After the foremost 

 egg in each hand has been candled, it is dropped back into the palm 



