CHAPTER. LL 
THE DIGESTIVE SYSTEM. 
THE TEETH. 
E great importance of the teeth of the horse as an index of age 
calls for a special notice and copious illustration. Points in de- 
termining the age are the following:—There are two sets of teeth, 
the temporary or milk-teeth, and the permanent, the same number be- 
ing on each jaw. 
The ¢emporary are twelve front teeth, or incisors, and twelve molars, or 
grinders. The permanent set has twelve incisors, twenty-four molars, and 
four canines or tushes tn the male. At birth, or within about ten days 
afterward, the two central incisors are found, and about the same time three 
molars on each side of either jaw appear; at six months, four more middle 
incisors are seen; about the eighth month, two corner incisors on each jaw; 
at one year, there is the full temporary set. During the second year are 
cut two molars on either side of each jaw—eight in all—making twelve inci- 
sors and twenty molars, of which twenty-four are temporary and eight 
(molars) permanent. At two years and a half two permanent incisors 
displace the two temporary central ones, and are distinguished by increased 
size anda dark mark in the center. Between three and four years the next 
incisors are displaced by permanent ones. Between four and five, the corner 
incisors are likewise changed, and about this time the twelve temporary 
molars are replaced by permanent teeth, to which are added the remaining 
molars of the mare’s mouth. At about four and a half, the four canines 
or tushes of the Zorvse are seen and become fully grown at five. At six the 
central incisors of the dower jaw lose the dark mark in the crown which 
appeared at about three, perhaps a little before. At seven, this mark dis- 
appears from the middle incisors, and at eight is worn from all of them. 
At ten, eleven and twelve, the mark disappears from the central, middle 
and corner incisors respectively of the upper jaw. We thus have a fair 
index to the age. The teeth becoming longer, their edges triangular (tushes 
round and blunt), dishonest men attempt to practice various impositions, by 
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