MALFORMED EGGS AND THEIR CAUSES 305 



germ, which can easily be distinguished by its whitish color and 

 circular shape. 



The function of the yolk is to nourish the chick for the first 

 few hours after hatching and during the early stages of its growth. 

 It is just as essential to the young chick as is the colostrum to the 

 calf. It supplies nutrients in easily digestible form, at the same 

 time exerting a laxative influence which starts the digestive 

 processesB. 



Composition of the Egg. — Aside from its shell, the hen's egg 

 resembles in its composition the adult bird. Wheeler gives the 

 following analysis: The dry matter of the egg, exclusive of the 

 shell, shows the following proportion of constituents, water not 

 considered: 49.8 protein; 3.4 ash; 38.5 fat. 



Considering the total dry matter in the whole egg, shell in- 

 cluded, we find the proportions to be: 38.5 protein; 35.6 ash; 

 25.4 fat. 



A fresh-laid egg with a good sound shell, including water, 

 shows the following analysis: 13.2 protein; 11.4 shell, 0.8 other 

 ash; 8.9 fat; 65.7 water. 



The ash found in the egg, aside from the shell, is rich in phos- 

 phate. The shell consists almost entirely of carbonate of lime. 



Malformed Eggs and their Causes. — Soft-shelled eggs are due 

 either to the absence of shell-forming material in the feed or to 

 lisease in the lower part of the oviduct which results in an insuffi- 

 cient secretion of lime salts. In rare cases, however, they may be 

 caused by the fowls not eating enough of shell-forming material, 

 even when an abundant supply is available. Sometimes the bird 

 is too fat, and this results in an absence of muscular tonicity, the 

 egg being passed do^\^l the oviduct so rapidly that the secretions 

 are not supplied in sufficient amount. 



In the ordinary course of eggs down the oviduct, they should 

 mature at such times that only one will be laid at a time; but in 

 consequence of improper feed, usually too much of carbohydrates 

 or fat, the bird deposits excessive fat, the organs contract and do 

 not permit the free passage of the ovum, finally one of two things 

 may result. Two ova may pass into the oviduct nearly at the 

 same time, or one may be held near the upper end until another is 

 formed there, when the combined force of the two will propel 

 them douTi the oviduct, this resulting in an egg being laid with 

 two yolks, — the commonly seen double-yolked egg, which is usually 

 of excessive size because of the twin yolks. 

 20 



