48 THE TEMPORARY UE^s'TITIOX. 



eral development, the foal lia^ no teeth at birtli, Ka- 

 ture providing a membrane-like cover for the incisors 

 as well as the hoofs. In two or three days, however, 

 the molars are all cut. The incisors are cut in pairs, 

 two above and two below. The first pair protrude in 

 from three to eight days, and attain their growth in 

 about two months. The second pair are cut when the 

 foal is five or six weeks old. They also attain their 

 growth in about two months. The time of cutting the 

 third pair varies. In some foals the\' appear as early 

 as the sixth month ; in others as late as the ninth. 

 They attain their growth in about three months.* 



The milk teeth are smaller and whiter and have 

 more distinct necks than the permanent. Their shin- 

 ing, milky-white color, M, Chauveau says, is due to 

 the thinness or absence of the cement, their crowns 

 being finely striated (not cannular) on the anterior 

 face, and their growth, unlike the permanent teeth, 

 ceasing when they begin to be used.f 



" M. Rousseau assigns from the seventh to the tenth month 

 as the period of the completion of the first or colt's mouth den- 

 tition. Tlie deciduous incisors have thinner and more trenchant 

 crowns than the permanent. — Owen, 



\ The absorption of the roots of the milk teeth bv the per- 

 manent would tend to prevent the coniiuuous growth of the 

 former ; but the real cause appears to be that continuous growth 

 is contrary to their nature. As the roots are conijicsed of 

 cement (except the dentine lining the pulp cavity), and as 

 they are absorbed, it naturally follows that much of the cement 

 surrounding the crowns of the permanent teeth is derived from 

 them (cement from cement), thus lesseninrr the drain on the 

 permanent tooth pulps, which are all the better able to supply 

 cement for the roots of the permanent teeth. The scarcity of 

 cement on the crowns of the milk teeth is probably owing to 

 the fact that they had no cement to absorb. The evil of extract- 

 inor healthy milk teeth is obvious^ 



