358 THE ANATOMY OF THE nORSE 



a knowledge of the ago of tlic liorsc after he has shed his luilk teeth, which 

 as a rule lie does in jKiirs at certain fixed periods. In order, therefore, to 

 be able to estimate the age of the horse from his teeth, it is necessary to 

 ascertain, as nearly as may be, the exact time at which he puts up each 

 pair of his milk or sucking teeth, and afterwards the periods at which they 

 are replaced b)' the permanent teeth. Finally, it becomes the province of 

 the veterinarian to lay down rules for ascertaining the age from the degree 

 of attrition which the permanent teeth have undergone. For these several 

 purposes, the horse's mouth must be studied from the earliest period of his 

 life up to old age. 



In horseman's language the incisors are called nippers, the canine teeth 

 tushes, and the molars grinders. 



By the end of the first year the colt has cut his twelve nippers and 

 sixteen grinders, which usually pierce the gums at the following months. 

 Before birth, the eight anterior grinders have generally shown themselves, 

 followed about a week after foaling by the two central nippers. At the end 

 of the first month another grinder makes its appearance all round, and in 

 the middle of the second the next nipper shows itself. By the end of the 

 second month the central nippers have attained their full size, and the 

 second are about half-grown, requiring another month to overtake their 

 fellows. Between the sixth and ninth months the corner nippers are cut, 

 and towards the end of the first year reach their full size. This first set of 

 nippers consists of teeth considerably smaller in size than the permanent 

 teeth, and somewhat difFei*ent in shape. They are more rounded in front, 

 and hollow towards the mouth, the outer edge being at first much higher 

 than the innei\ As they wear down, these two edges soon become level, 

 but the corner nippers maintain this appearance for a long time. At six 

 months the central nippers are almost level, with the black "mark" in 

 their middle wide and faint ; and about the ninth month the next nipper 

 on each side above and below is also worn down almost to a level surface. 



During the second year the following changes take place : — In the first 

 month, and sometimes towards the end of the first year, a fourth grinder is 

 cut all round, which commences the set of permanent teeth, the three first 

 molars only being shed. At a year and a half, the mark in the central 

 nippers is much worn out, and has become very faint ; the second is also 

 worn flat, but is not so faint ; and the corner nippers arc flat, but present 

 the mark clearly enough. In colts which have been reared on cora and 

 much liay, the wearing down proceeds more rapidly than in those fed upon 

 grass alone. 



The third year is occupied by the commencement of the second dentition, 

 which is effected in the same order in which the milk teeth made their 

 appearance. Both sets are contained within the jaw at birth, the permanent 

 teeth being small and only partially developed, and lying deeper than the 

 milk teeth. As the mouth grows, it becomes too large for its first set of 

 teeth ; and the roots of these being pressed upon by the growth of the 

 permanent set, their fangs are absorbed, and allow the new teeth to show 

 themselves, cither in the places of the former, or by their sides, in which 

 case they arc known by the name of ivoJf's teeth. This change proceeds in 

 the same order as the cutting uf the milk teeth, commencing with the first 

 grinder, which is shed and replaced by a permanent tooth early in the 



