216 NAVIN ox THE HORSE. 



then take a seton-needle and pass it down into the bottom of 

 the abscess, and out at the side of the neck, and keep this 

 hole open so that the matter will run out of it. The crooked 

 blade of the seton-needle enables one to perform this opera- 

 tion easily. 



SPLINT. 



This is a callous, hardened, or bony tumor, or lump, grow- 

 ing on, or near, one of the splint-bones. 



In order to clearly understand this difficulty, it will be 

 necessary to consider the structure of the parts wdiich are the 

 seat of the affection. 



The leg is composed of three bones, namely, the cannon and 

 two splint-bones. The cannon extends from the knee to the 

 fetlock-joint. It is a long and round bone, and at the uj^per 

 end, where it unites with the bones of the knee, is marked by 

 a high ridge running from the back to the front of the head 

 of the bone, and another ridge at each side, thus presenting a 

 double pully-like surface, admitting of a backward and for- 

 ward motion, but no lateral or side motion. At the back of 

 the cannon-bone, and to the outer and inner edges of it, are 

 situated the two splint-bones. These have a head, and grad- 

 ually taper off to a point, being thin and flat ; they are some- 

 what thick at the top, but get thinner toward the point. The 

 heads of these bones help to form the surface on which the 

 three lower knee-bones rest; indeed, the inner sj^lint-bone 

 alone supports the inner knee-bone. The splint-bones extend 

 a little more than half-way down the cannon, or shin-bone, 

 lying with their flat surfaces to it, and firmly united to it by a 

 strong, tough, and very elastic substance, called fibro-carti- 

 lage, throughout their whole length, which admits of but little 

 motion. The chief object of these bones is to form a large 

 surface for the bones of the knee to rest upon, and, by their 

 peculiar elastic union with the cannon-bone, to break the 

 force of the weight of the animal when thrown on them. 



