THE HORSE, SKIN DISEASES, ETC. 291 



annoyed with flies, keep the wound covered with a rag moistened in x 

 solution of tar. 



XIX. Fisttda. 



Causes. — This is sometimes known as fistulous withers ^ to distinguish 

 it from fistula of the parotid duct. It is similar to poll-evil and is gen- 

 erally caused in like manner, by bi^ises. In the case of fistula, these 

 bruises may be caused by an ill-fitting collar ; by a lady's saddle, partic- 

 ularly if awkwardly ridden; by the pressing forward of a man's saddle, 

 especially in case of high withers ; by striking the withers against the 

 top of a loAV door-wa}^ ; by rolling and striking the withers against soni*» 

 hard substance ; by the biting of other horses ; and by a blow of the 

 blacksmith's hammer. The points of the spinal processes, (little pro- 

 jections of the spine or back bone,) are hurt, inflammation sets in, and 

 the fistulous tumor is produced. Its site is the spine above the shoulders ; 

 and it is more troublesome than poll-evil, because it is more exposed to 

 repeated injuries. 



How to know it — The first indication will be a swelling on one or 

 both sides of the withers, generally rather broad and flat. Upon exam- 

 ination with the fingers this will be found hot, tender, and apparently 

 deep seated. If observed when first formed, it will be of unifori? 

 hardness throughout. If unattended to while in this state, the tumor 

 soon becomes an abscess ; and owing to the difficulty in the way of the 

 matter's escaping, (its natural outlet being at the top of the shoulders), 

 the pus sinks downward ; and the abscess sometimes becomes enormous 

 before there is any well defined head, and before there is any opening. 

 When it breaks, or is opened, a large quantity of extremely offensive 

 matter flows out. Ordinarily, the tumor will come to a head in from one 

 to two weeks. When the discharge has begun, the tumor does not begin 

 to grow healthy and heal, but the walls of the opening thicken, and 

 continue to discharge matter which becomes more and more offensive. 

 The matter burrows between the shoulder blade and spinal points, and 

 everything around seems to be rotting away ; and it is both difficult and 

 dangerous to trace the opening. In process of time several holes will 

 •ppear along the course of the muscles in contact with the original abscess, 

 and from each issues a foul discharge, till the ulcerating process seems 

 to extend itself to nearly all the muscles of the shoulder. 



The health of the animal may at first be excellent, and there may be 



no lameness ; but as the inflammation extends, there is lameness of the 



shoulder, and he suffers generally — often greatly. He is averse \<\ 



motion, and will suffer for food and drink rather than undergo the pai« 



19 



