306 VETEKINARY MEDICINE AND SURGERY. 



completion of the second year a fifth molar, also a permanent tooth, shows 

 itself. 



About two and a half years old the two anterior temporary molars are 

 replaced by jjermanent teeth, and between three and four the remaining, 

 or third, temporary molar is similarly replaced; and about the same time 

 the last or sixth permanent molar begins to appear. Thus when the 

 mouth is completed, there are six permanent molars in each jaw, or 

 twenty-four in all. 



These structural changes afford a very good index of the age of the 

 horse up to the period when they are completed, namely four years old. 

 The molars, however, are seldom referred to, because their position at the 

 back of the mouth renders their examination inconvenient and often very 

 difficult. Neverless, it is useful to be acquainted with the structural 

 changes of these teeth in cases where there may be a doubt as to the true 

 age, as indicated by the incisors. After four years old, the molars are 

 not often taken into consideration in determining the age of the horse. 



A supplementary molar known as a ''Wolf's tooth," sometimes ajj- 

 pears in either jaw. Such teeth seldom cause any inconvenience. If 

 they do so, they can easily be removed by the pincers, as they are only of 

 a rudimentary character. 



The Anterior Teeth, or Incisors, are six in number in each jaw, 

 when the mouth is complete ; and in the immediate rear of these in 

 males, there is usually added one very peculiar pointed tooth on each 

 side in each jaw, called a tusk. Though there are two crops of incisors, 

 yet there is but one of tusks. In fact, these teeth, though they begin to 

 appear about four years old, are not usually fully developed until the 

 last permanent incisor is more or less up. 



The upper incisors are considerably longer and larger than the lower. 

 Distinction hetween Temporary and Permanent Incisors. — 

 Temporary, otherwise called Milk, are easily distinguished from Perma- 

 nent incisors by the following well-marked signs, namely, they are small- 

 er, whiter, and have more distinct necks. They are smooth externally, 

 and grooved on the inside, jirobably in order to enable the foal more 

 easily to grip the teats of the dam. Their fangs are small and have but 

 little attachment to the gums. The jaws are plump, fleshy and round, 

 and the teeth are arranged in something like a semicircle. 



Permanent teeth, on the other hand, are larger, broader, wider in 

 their necks, grooved externally and smooth internally, and more discol- 



