BREEDING 95 



excluded, and taken up by the oviduct at the same time 

 and wrapped in the same albumen, shell membranes, and 

 shell. A second way is by the premature rupture of a follicle, 

 which allows the yolk to escape into the body cavity. This 

 yolk is sought out and taken up by the oviduct, often just 

 before or after another yolk has been received from the ovary. 

 These two yolks then travel down the oviduct together, as 

 in the first case. In either case one or both of the yolks may 

 be fertile and develop a chick, though such eggs rarely 

 hatch. 



The so-called soft-shelled egg is usually one that has no 

 shell at all. This may be caused by the shell gland faiUng 

 to function or by the peristaltic constrictions becoming so 

 violent as to hurry the egg to exclusion, without allowing time 

 for the secretion and deposit of the shell. 



When the shell material is first applied to the egg it is 

 plastic and the oviduct on the outside and the egg on the 

 inside together constitute a mould which determines the 

 shape of the egg. For some reason that part of the oviduct 

 which immediately surrounds the egg sometimes becomes 

 constricted, taking on what is termed an hour-glass form. 

 The result is that as the shell material hardens it takes the 

 same form, becoming what is called, for want of a better 

 name, a "dumb-bell" egg. 



Of quite common occurrence are the very tiny eggs which 

 have no yolk. These are caused by some foreign substance, 

 as a clot of blood or a piece of detached membrane, finding 

 its way into the oviduct and travelling down in the same way 

 that an egg does. As it comes to the albumen secreting 

 portion, the gland is stimulated and secretion occurs, much 

 as though a yolk were present. After being surrounded by 

 albumen the substance has the same history as a normal egg. 



It sometimes occurs that what appears to be a double- 

 yolked egg is found upon being opened to contain another 

 egg in every way normal, instead of the expected two yolks. 

 For some reason, after the egg is completed and is ready for 

 laying, the constrictions that usually take place behind it, 

 forcing it toward exclusion, become reversed and take place 

 in front of the egg, forcing it back into the albuminous 



