120 DISEASES OF SHEEP. 



must the dung be removed, and all objects brushed over 

 with whitewash to which chloride of lime has been added. 



TO TELL THE AGE OF SHEEP. 



The age of sheep, like that of tlie other domestic animala, 

 may be determined from the change and condition of the 

 teeth. This is certain up to the sixth year inclusively, and 

 tolerably sure after this age. The sheep, like the ox, has 

 eight incisors, which are all situated in the lower jaw, 

 as in all ruminating animals. The visible part of the 

 teeth which projects above the gums is called the crown, 

 At its lower end, the crown becomes thinner and is en- 

 veloped in the gum. This part is called the neck. The 

 lower end of the tooth, which tapers to a point and is 

 situated in the socket, is called the root. ' All the teeth are 

 placed loosely in the sockets and admit of more or less mo- 

 tion. The two middle teeth are called the tongs or gath- 

 erers; the two on each side, the inner middle teeth; and 

 the next on each side, the outer middle teeth. The two ex-' 

 ternal ones are called the corner teeth. 



In new-born lambs the two gatherers are just visible above 

 the gums ; after six or eight days, the two inner middle 

 teeth, and after four or six days more the two outer middle, 

 teeth, make their appearance. Six or eight days later 

 the two corner teeth may be seen ; so that in three weeks 

 after birth the sheep has its full complement of incisors. 

 These teeth, called milk-teeth, become longer and broader, 

 and reach their full development at the end of the first 

 year. Their upper edge, or edge of the crown, is some- 

 what pointed. 



The milk-teeth remain from eighteen to twenty months, 



