The Egg. 19 



guidance should be, "Only a perfect egg produces the perfect 

 chick " ; and when care is used in selecting the eggs there will 

 be but few failures in hatching. 



HOW THE EGG IS PUT TOGETHER. 

 HENRY STEWART. 



An egg is not simply a mass of yelk surrounded by a layer of 

 albumen and inclosed in a shell, but consists of a vitalized 

 germ imbedded in a mass of yellow yelk composed of several 

 layers and surrounded by a tough membrane known as the vi- 

 telline membrane, which is shown in the accompanying draw- 

 ing, the yelk being at i and the inclosing membrane at 2. 

 This yelk is the fertile part of the egg and is developed in the 

 ovary. As it descends the oviduct, it becomes inclosed in a 

 thick layer of albumen, consisting of three distinct films, each 

 of a different density (2, 3 and 4 in the figure), and these are 

 deposited around the yelk at three different periods during its 

 descent along the oviduct. This albuminous covering is ine 

 closed in a double lining membrane of a tough, fibrous char- 

 acter, which is the covering of those imperfect eggs known as 

 soft-shelled eggs, and which are without any solid shell. Im- 

 mediately over this and attached to it is the outer shell, which 



consists chiefly of 

 carbonate of lime. 

 This outer shell con- 

 sists of several lay- 

 ers of fibrous tissue 

 woven together, and 

 its opacity is due 

 to air contained in 

 the meshes of the in- 

 terlaced fibers. It is 

 porous and admits 

 the passage of air 

 freely through the tissues. At 6 is shown a spiral albuminous 



