DOMESTIC ANIMALS. 



63 



pretation lias been a fruitful cause of dissension, among 

 veterinarians, and a source of a great deal of litigation 

 between buyers and sellers of horses. It will be my 

 aim to make the description of the changes that take 

 place in the hock joint as a result of disease leading 

 to the enlargement called spavin so plain that the or- 

 dinary reader will have a tolerably clear perception of 

 them. As will be seen in Fig. 24, there are a num- 

 ber of small bones entering into the 

 formation of the hock joint (in the 

 young animal there are 9), Between 

 those various bones there is very little 

 motion at any time, yet it may be as- 

 serted that in the normal condition 

 some motion is allowed. The bones 

 are held together by a strong kind of 

 fibre a kind of gristle. It quite 

 frequently happens that from some 

 cause or other an inflammation is 

 started in either the bones themselves or 

 in the fibrous structures which hold 

 them together. If this inflammation 

 becomes extensive,or is long continued, 

 one of two things happens : either 

 portions of the bone or bones ulcerate 

 and waste away, causing what is 

 known as necrosis, or the opposite condition is the 

 result, viz: that there is new material of a bony nature 

 added to existing structures, filling up the space be- 

 tween the bones and of course destroying what little 

 motion is normally present. Now, we can have this con- 



Fig. 21. Hind leg 



showing bones 



of hock. 



