FIRST PERIOD. 



ERUPTION OF THE INCISORS OF FIRST DENTITION. 



At Birth, — At the birth of the foal the incisors have not 

 yet pierced the gums. The anterior border of the pincher and 

 intermediate teeth can be seen under the mucous membrane, 

 which is rendered paler than the surrounding tissues by their 

 pressure. (Figs. 32, 33, 34.) 



About One Week. — The pincher teeth have generally ap- 

 peared in from six to eight days, the upper teeth preceding the 

 lower by twenty-four or forty-eight hours. At this age the 

 teeth are of little importance; for the general aspect of the 

 animal, its manner of walking, which is still unsteady, and 

 the condition of its hairs show that it is but a few days old. 

 (Figs. 35, 36, 37.) 



About One Month. — The intermediate teeth appear between 

 thirty and forty days, just as the interior border of the pincher 

 teeth commence to be worn. (Figs. 38, 39, 40.) 



About Three Months. — There are now four teeth in the 

 upper and four teeth in the lower jaw ; the pinchers have com- 

 menced to wear on their posterior borders ; they are entirely free 

 from the gum. (Figs. 41, 42, 43.) 



About Four Months. — The incisive arch has become wider ; 

 the inferior intermediate teeth are free from the gum; their 

 anterior border has commenced to be worn away toward their 

 inner edge as it comes in contact with the corresponding supe- 

 rior teeth. (Figs. 44, 45, 46.) 



About Five Months. — The pincher teeth have pushed through 

 the gums to the line of the neck of the teeth ; the intermediate 

 teeth are worn on their anterior borders ; the mucous membrane 

 is ollen sensitive along the posterior border of these teeth on 

 account of the corner teeth, which have commenced to push out. 

 (Figs. 47, 48, 49.) 



(53) 



