36 OF THE TEETH. 



puffy swelling is discovered within the bend, it is termed 

 a hog spavin ; which is the consequence of too large a 

 secretion of joint oil, thereby distending the sac of the 

 joint. A mucous capsule above and behind the hock also, 

 at times, becomes enlarged, and is then called thorougkpin. 

 At the back, likewise, of the joint the ligaments are liable 

 to extension or other violence, when the part, instead of 

 exhibiting a straight line from the point of the hock down- 

 wards, presents in this case a curved surface, accompanied 

 with heat and tenderness, which is called a curb. The 

 inner part of the joint at its bend or ply is subject also to 

 a similar scabby eruption to that of the fore legs, called 

 sellenders. To detect the existence of hone spavin, the 

 hocks should be attentively viewed from behind, when any 

 enlargement in the place of spavin, may be easily detected. 

 From this enumeration, it will be evident that a strict ex- 

 amination of the whole joint is very necessary in the pur- 

 chase of a horse. In the consideration of the parts below 

 the hock, what has been said of the fore extremities applies 

 equally to the hinder. 



OF THE TEETH, AS CHARACTERIZING THE AGE. 



As it is necessary to obtain some marks whereby w^e 

 can ascertain the age of the horse, the ingenuity of man 

 has employed itself in noticing those changes in the organs 

 which are most readily observed, and the least liable to 

 variation. The teeth, as a part of the bony structure, 

 have been happily seized on for this purpose. We shall 

 here consider the teeth as indices of age only ; reserving a 

 more general sketch of their anatomy and physiology, as 

 masticatory organs, for a future opportunity. It is well 

 known that the usual indications of the age of the horse 

 are commonly derived from certain marks in the incisor 

 teeth, and principally from those of the lower or posterior 

 jaw. These ynarks consist in a funnel-like cavity in each 

 of these teeth ; each is also covered over with two coats, 

 one, the outer one, of a brown tough substance called 

 crust a petrosa, and an inner one, which is very brittle and 

 hard, called enamel. As these coatings of the tooth reach 

 its nipping edge, they pass over the plane surface, and then 



