THE PRISONER BREAKING THE WALL. 301 



chicken, just above the point, there will be seen a 

 small horny scale, nearly circular, having at its 

 centre a hard and sharp projecting point: this 

 sharp point it is which, impelled by the head 

 against the side of the shell, ultimately effects its 

 perforation." After the chick leaves the shell the 

 scale falls off, leaving only a light-coloured mark 

 to indicate the place where it had been. Where 

 the shell is very thick, as in the ostrich, it is pro- 

 bable that this horny appendage is proportionately 

 thickened. 



The result of the first strokes of the bill of the 

 chick is a small crack, shown 

 in the cut. The blows are 

 often hard enough to be caught 

 by a quick ear, and Reaumur, 

 by examining an egg in this 

 state by candle-light, saw the 

 action of the chick in its endea- 

 vours to break down its dun- 

 geon wall. Some of the pieces 

 fly off to a little distance from 

 the egg ; the chick pecks at one part of the shell 

 until it is fractured, and then it appears to turn a 

 little round and peck a little further on. At all 



