THE EGG 25 



enclosed the egg which projected from the opening; in others 

 finally the empty capsule had just deposited the egg in the en- 

 trance of the oviduct." According to Patterson the funnel of 

 the oviduct becomes inactive as soon as an egg is received, but 

 about the time of laying it becomes highly active and again clasps 

 an egg follicle. 



The existence of double-yolked eggs renders it probable that 

 the oviduct can pick up eggs that have escaped into the body- 

 cavity. But in some cases ova that escape into the body-cavity 

 undergo resorption there. 



Immediately after the ovum is received by the oviduct a 

 special layer of albumen is secreted which adheres closely to the 

 vitelline membrane and is prolonged in two strands, one ex- 

 tending up and the other down the oviduct; these strands become 

 the chalazse; the layer to which they are attached may, therefore, 

 be called the chalaziferous layer (Coste) of the albumen. The 

 hne joining the attachments of the chalazse is at right angles to 

 the main axis of the ovum (that passing through the germinal 

 disc) ; it is obvious, therefore, that there must be some antecedent 

 condition that determines the position of the ovum in the oviduct; 

 this is probably the position of the ovum in the folHcle, i.e., the 

 relation of the germinal disc to the stigma, for the folUcular 

 orientation is apparently preserved in the oviduct. The question 

 is of considerable importance because, as we shall see, the axis of 

 the embryo is later bisected by a plane passing through the 

 chalazse, and is therefore certainly determined at the time that 

 the chalazae are formed, and Bartelmez even traces it back to the 

 earliest stages of the ovocyte. 



After formation of the chalazse the ovum passes down the ovi- 

 duct, rotating on the chalazal axis, and thus describing a spiral 

 path; the albumen which is secreted abundantly in advance of 

 the ovum is therefore wrapped around the chalaziferous layer 

 and chalazse in successive spiral layers and the chalazse are re- 

 volved in spiral turns. 



Only about 50 % of the white of the egg is formed by the albu- 

 men secreting portion of the oviduct; this is in the form of a 

 dense layer formed of matted fibers; the shell membrane is de- 

 posited directly on this; and the more fluid portion of the albumen 

 constituting 50% or more of its entire bulk enters through the 

 shell membrane while the egg is in the isthmus and uterus (Pearl 

 and Curtis, 1912). 



