Diseases of the Skin. ^41 



of the skin, and appear to be due to some special form 

 of local irritation. They are to be seen on the free 

 edges of the ears, lips, and especially the eyelids ; and 

 in some animals the mucous membrane of the mouth 

 and prepuce is a common location. Other parts of the 

 skin are also liable to invasion, but probably not so 

 frequently as those already named. The enlargements 

 partake of a variety of forms. They are sometimes 

 diffuse, or spread over the surface of the skin, at others 

 they rise erect, and subsequently assume a spherical or 

 other form, being very mobile, and united to the tissues 

 of the true skin by a narrow cord-like neck. Their 

 presence gives rise to various forms of inconvenience, 

 such as friction against other objects, laceration, &c., 

 and considerable irritation in old-standing cases by the 

 cracking of the scales, and subsequent ulceration between 

 them. 



Treatment. — In the diffused variety the regular appli- 

 cation of caustic, as the nitrate of silver, or strong acetic 

 acid, will be required. Those attached to the skin by a 

 constriction or neck, are easily removed by ligature, 

 torsion, or the ecraseur. Early attention when the 

 growths are small is likely to be of greatest service. 



Parasitic Diseases of the Skin. — The affections of 

 tins class are numerous and important. They arise from 

 the irritation produced as the result of the efforts of the 

 animal parasites in obtaining a nidus or hatching-place 

 for their eggs. Some of these occupy their position for 

 such a length of time when undisturbed as to indicate 

 the permanence of their home ; others are ephemeral in 

 their visits, being endowed with organs of free Icco- 

 m.otion, as legs and wings of considerable power. In 

 the first order we place the various forms of mange, or 

 itch animalcules, and in the latter, fleas, ticks, lice, and 

 other insects, amongst which the harvest bug is a common 

 example. In addition to these, we have also to notice 

 another variety — viz., vegetable parasites, which likewise 

 prove exceedingly troublesome to canine animals, as 

 well as disappointing to the hopes and aspirations of the 

 owner. 



16. 



