30 THE SURGICAL ANATOMY OF THE HORSE 



ot the food, etc., the examination of the teeth remains nevertheless up 

 to a certain period of life one of the most potent methods we possess 

 of determining the age. The times given below are of course 

 only approximate, but they may be reasonably accepted as being the 

 most constant. 



When the horse is one year old all the temporary incisors are present, 

 and each jaw also carries six temporary molars, three on either side. In 

 addition a fourth molar is found, which has made its appearance 

 through the gum, but is not so well developed as the remaining three. 

 This is thtjirst permanent molar. 



At two years old the animal's mouth presents some little difficulty. 

 The incisors are showing signs of wear. The cup-like cavities on their 

 tables have disappeared, and the tables themselves are flat, and present a 

 faint striation. It is most important to be on one's guard in distin- 

 guishing between these and permanent incisors. At this age the 

 molars form the better guide, for an additional permanent molar has made 

 its appearance, so that we now have five present, three of which are 

 temporary and two permanent. 



The middle temporary incisors are cast, and the first pair of per- 

 manent incisors burst through the gums at two years and six months. 



When the horse attains the age of three the Jirst and second {in position 

 counting from the front but numbers three and four in age) permanent 

 molars cut through the gums, pushing before them the first and second 

 temporary teeth beneath which they have developed. These, of course, 

 are not yet the height of numbers four and five. The supplementary 

 molars or wolf's teeth are most frequently cast simultaneously with the 

 shedding of these two temporary molars. The first pair of permanent 

 incisors are now well up, and their tables are level with those of the 

 adjacent teeth. 



The second pair of permanent incisors (the laterals) appear through the 

 gums at three years and six months, and their tables are on a level with 

 those of the first permanent pair when the horse attains the age of Jour. 



