BROKEN KXEE. 247 



white and yolk to be removed without breaking the skin. Let 

 this skin now be pkiced in a hollowed cavity in the end of one 

 stick, and the rounded end of another placed on it, and you 

 will be enabled to perfectly understand the arrangement of this 

 membrane in a movable joint. This membrane is called the 

 synovial membrane; and its smooth surface constantly secretes a 

 fluid for the purpose of keeping the joint free, as if it were 

 oiled. This fluid is called spiovia, joint-water, or joint-oil, and 

 its presence is absolutely indispensable to the health and free 

 motion of the joint. These bones, forming the knee-joint, are 

 all firmly bound together and held in their places by strong 

 ligaments and bands, so arranged as to permit a free backward 

 and forward motion, but no other, and also forming a complete 

 covering of the whole joint to guard it against injury from out- 

 ward violence. 



To guard against concussion or jar, it will be seen that there 

 are, in the knee-joint, six layers of thick, elastic cartilage, six 

 layers of synovial membrane, and two layers of synovial fluid, 

 or joint-oil. Were it not for this admirable provision of na- 

 ture, the concussion, even in an ordinary gait, would be so 

 great as to do irreparable mischief; and who could tell the 

 result to the hunter, who comes down with a force equal to 

 several thousand pounds weight in leaping a fence or a ditch? 



Broken knee is generally produced by the horse falling, for 

 when he falls the knee is thrown forward, and the whole force 

 of the body comes on it, and if it comes in contact with a stone 

 or any hard substance, or even the hard ground, injury of 

 greater or less extent is very likely to be the result. The knee 

 may be cut by a kick or by being struck against any sharp- 

 edged substance. 



However the injury may occur, it is one of more than ordi- 

 nary importance. The cut may only be through the skin, or 

 down to the ligaments covering the knee-joints, or it may i^ass 

 through these ligaments to the bones of the knee, or even into 

 the cavity of the knee-joint, opening the joint and letting out 



