TUMOURS OP THE LIPS ANJ) CHEEKS. 



249 



Encysted tumours also occur frequently on the lips of horses ; 

 they lie close under the mucous membrane, sometimes attain the 

 size of a pigeon's egg, and contain a thick, fluid, honey-like material. 

 They are really retention cysts, produced by obstruction of the ducts 

 of mucous glands. So long as they attain no considerable size, 

 nor become the seat of inflammatory changes, they are seldom 

 observed. To detect , them, the thumb is laid on the external 

 skin, the fingers on the mucous membrane of the lip, which is 

 allowed to glide slowly through the fingers. When such tumours 

 become inflamed, they cause enlargement of the submaxillary lymph 

 glands, displace the lips, and impart to the face somewhat of 

 the appearance of facial paralysis. If they become inflamed, or 

 interfere with feeding, treatment 

 will be required. It is generally 

 sufficient to lay open the parts 

 and dress the interior with nitrate 

 of silver, sulphate of copper, 

 2 per cent, corrosive sublimate 

 solution, or 10-20 per cent, 

 solution of chloride of zinc. 



Atheroma. A cyst develops 

 above the base of the false 

 nostril in horses, usually result- 

 ing from occlusion of a sebaceous 

 follicle. It is filled with a gran- 

 ular material. It may become 

 as large as a hen's egg, is 



round, painless, and freely movable, but seldom causes any 

 difficulty in breathing. By passing the finger into the false nostril, 

 it may be readily felt, and is sometimes visible from without. 

 (Fig. 269.) Such growths are seen oftenest in young foals. They 

 are easily removed. The animal is cast — though in very quiet 

 subjects this is scarcely necessary — and an incision made through 

 the skin in the long direction of the head. The cyst is then 

 grasped with forceps and freed from its surroundings, care being 

 taken not to incise it, as its removal is thus rendered more difficult. 

 Should such an accident happen, a dark-grey, granular material is 

 discharged, and the inner wall of the cyst comes in view. The 

 nasal mucous membrane being firmly adherent to the swelling may 

 be injured, when froth from the nostril will appear in the wound. 

 But even where the mucous membrane has been cut, healing by 

 primary intention occurs, The wound is at once sutured, and finally 



Fig. 269.— Atheroma of the false nostril. 



