GALLUS DOMESTICUS. 



residue having the leading characters of albumen, but contain- 

 ing phosphorus in some peculiar state of combination ; the 

 alcoholic solution is yellow, and deposits a crystalline, fatty 

 matter, and when distilled leaves a yellow oil. The use of 

 the phosphorus is to yield phosphoric acid to form the bones 

 of the chick, but the source of the lime with which it is com- 

 bined is not apparent, for it has not been detected in the soft 

 parts of the egg, and hitherto no vascular communication has 

 been discovered between the chick and the shell. 



The shell of the egg is lined throughout with a thin but 

 tough membrane, called pellicula ovi, which, dividing at or 

 near the obtuse end, forms a small bag, the air follicle. 

 This membrane weighs about 2.25 grains in a common or 

 usual sized egg. It contains what is called the albumen or 

 white, and the vitellus or yellow. The white consists of two 

 distinct parts, one of which is a delicate membrane forming a 

 series of cells which inclose the other or fluid part. It has 

 the well-known property of being coagulated by heat. The 

 yelk consists of oil, suspended in water, by means of albumen, 

 and held in a membranous sack, the yelk-bag, each end of 

 which is twisted, to form what is called the chalaza intended 

 to preserve the yelk in such a position that the cicatricula or 

 rudimental embryo shall always be uppermost. The egg 

 loses two or three per cent, of its weight when boiled in 

 water. The white is more easily digested than the yelk, and 

 both are more digestible in the soft than in the hard state. 

 Hen's eggs are decidedly wholesome, and when new-laid are 

 an agreeable and nourishing food. 



Eggs are preserved any length of time by greasing them 

 well over with butter or lard, when warm from the nest. It 

 keeps out the air, arid, preventing the admission of air through 

 the pores of the shell, preserves eggs for a longer period than 

 they otherwise would be kept good. Fresh-laid eggs are 

 easily known by holding them up to a bright light. If the 

 inside appears semi-transparent and fluid, and the yelk in the 

 centre, it is a fresh egg. On the contrary, if it looks turbid, 

 opaque, or irregularly clouded, it is a stale one, and should be 

 rejected. Also, if an egg held up to a bright light shows a 

 small vacancy at the top of it within, it will produce a male 

 bird ; on the contrary, if the little vacancy is observed at the 

 side of the egg, it will prove a female. (Main's Domestic 

 Poultry, p. 253.) 



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