430 HEALTH AND DISEASE 



and scraped, and treated as an ordinary wound. In some chronic cases 

 the orifice has been caused to close by touching it lightly with the actual 

 cautery. 



FISTULOUS AVOUNDS 



POLL EVIL 



This term signifies a wound on the poll, or that part of the neck 

 immediately behind the ears. It usually consists of one or more sore places 

 in the skin communicating by pipes (sinuses) with a cavity seated more 

 or less deep down in the tissues, sometimes extending to the bones, the 

 whole constituting what is termed a " fistula ". 



Causes. — It is caused by an injury, frequently inflicted by the horse 

 striking his head against some hard substance, as a low beam, ceiling, or 

 doorway, or against the floor or wall in the act of rolling, or by a violent 

 blow with any hard substance, as a whip-stock, fork-handle, &c., bruising 

 the skin and underlying structures so as to interfere with the circulation 

 of the part. It has also been caused by stretching these parts by the 

 injudicious use of the bearing- rein, and by badly-fitting or heavy bridles 

 chafing the poll. 



The symptoms at first depend a good deal ujion the severity of the 

 injury. If this be slight we may only find a small swelling on the nape of 

 the neck, which soon passes away again after a short period of rest, even 

 without any treatment at all. At others there is a small hard knot left, 

 which upon the slightest injury — and with such a swelling injuries are 

 easily inflicted — rapidly enlarges to the size of a cricket ball or more. This 

 swelling is very painful to the touch, and causes the animal to carry his 

 head in a stifi" manner, with the nose slightly poked forward and upwards 

 to relieve the tension of the muscle at the back of the neck. After a time 

 — usually from one to three weeks — there appears a soft place on tlie 

 swelling, which shows us that the part has gathered and formed matter 

 (pus), which has found its way to the surface (pointed). If not opened it 

 will soon burst through the skin and discharge a thin yellowish-red matter, 

 which after a few hours changes to a yellowish-white colour. 



When the matter is allowed to remain pent up in the tissues, it will 

 burrow between the muscles in all directions, and occasion a wound with 

 several pipes (sinuses), which proves, as a rule, a very formidable one to 

 cure, particularly if the pax-wax or great ligament of the neck, or the bones 

 below, become involved. The matter (pus) may run down the neck between 

 the muscles — even as low as the shoulders, as we once had occasion to 

 observe; or the neck bones (cervical vertebrae) may become diseased. 



