160 NON-PARASITIC SKIN DISEASES. 



Surfeit {^Urticaria or Netile-rash). 



This term is applied to an eruption of small irregular lumps or 

 boils, more or less painful to the touch, which, as a rule, break out 

 suddenly on the horse's body and neck, and in rare oases on his 

 limbs. A favourite seat of this eruption in saddle-horses is the 

 bearing surface of the saddle on the upper part of the back, and 

 especially under the cantle ; probably because there is more motion 

 at the cantle than at the pommel, on account of the forward posi- 

 tion of the girths. Sometimes, after two or three days, the lumps 

 form scabs, which usually fall off during the course of a week, and 

 leave behind a hairless and more or less round patch of skin, of, 

 say, a quarter of an inch in diameter. These spots generally 

 remain as permanent marks on the coat. If, in a dark-skinned 

 horse, the inflammation has been sufficiently severe to destroy the 

 layer of pigment in the skin of the part, the spots will be white, 

 with, usually, white hairs in them. The destruction of a portion 

 of the pigmentary layer need not necessarily involve that of the 

 contained hair follicles. On a grey or white horse which has a 

 dark skin, a slight attack of surfeit may leave a number of black 

 spots showing through the light-coloured coat. The presence of 

 these painful lumps on the back of a saddle-horse may become 

 known to the rider by the fact of the animal acting, when being 

 mounted, as if he had a sore back. 



The usual cause of surfeit is supposed to be the consumption of 

 food which upsets the animal's digestive organs ; for the skin being 

 continuous with the mucous membrane of the intestinal canal, a 

 disturbance of the one structure is readily communicated to the 

 other. The horses in South Africa frequently suffer from surfeit ; 

 apparently owing to the extremely dry nature of the forage during 

 the greater part of the year. In men, the formation of wheals is 

 the special characteristic of urticaria. From a consideration of 

 the nature of the attack and course of the disease, surfeit is 

 probably often of parasitic origin. 



TREATMENT.— Good results are usually obtained from smear- 

 ing over the lumps and sores with mercurial (blue) ointment. 

 Sometimes, putting the affected horse on carrots or green food and 

 giving him 4 oz. of Epsom salts a day in a mash, will be sufficient. 

 Give a linseed mash every night, mix in it an ounce of bicarbonate 

 of soda, and apply (4) or (5), as mentioned on page 152. The 

 bicarbonate of soda has a soothing effect on the mucous membrane 

 of the intestines; and the good influence of linseed, in oases of 



