194 POULTRY PRODUCTION 



insure the complete checking of development, eggs must 

 be kept in a temperature below ().S° F. Practical experience 

 seems to indicate that eggs held in a temperature that is 

 even as possible, lying between the limits of 55° and 65° F., 

 give best results. Just what tlie temperature is at which 

 eggs begin to sliow the efi'ccts of chilling has not been deter- 

 mined so far as the author is aware. The jjlace most likely 

 to furnish the best holding condition is a cool, well-ventilated 

 cellar. 



Turning Hatching Eggs. — As already pointed out, the yolk, 

 with the germ spot uppermost, tends to float on the albumen. 

 It is prevented from coming in actual contact with the shell 

 membrane by the dense layer of albumen which surrounds 

 it. When left in the same position for a considerable time 

 a constant though gentle tendency upward parts the coat of 

 dense allnimen and allows the germinal disc to come in 

 contact with the shell membrane. With evaporation 

 constantly taking place the tiny embryo becomes adhered 

 to the membrane and is destroyed. When the eggs are not 

 allowed to remain in the same position, but are turned 

 fairly frecjucntly, a new point of contact is given, and more 

 albumen brought between the germ and the shell membrane. 



Jackson' reports, as the result of experiment, that after 

 the first two weeks there was a distinct advantage in keeping 

 eggs on their side and turning daily over, keeping them in 

 any other position or without turning. It is considered good 

 practice to turn all eggs dailv during the whole time thev are 

 held. 



Washing Hatching Eggs. — Eggs that are stained or dirty 

 are frecjuently washed with the hope of increasing their 

 hatching power. As a protection against disease, hatching 

 eggs are often washed in alcohol or other disinfectant. 



\^■asIling eggs destroys their protective coating, called the 

 cuticle or bloom, and allows more rapid evaporation. As 

 shown elsewhere, when artificial incubation is practised, 

 evaporation is likely to be abnormally rapid, and any practice 

 which increases evaporation should be looked upon with 



- Pciiiisj 1\ aiiia I'.ulletin No. 120. 



