DISEASES OF THE SKIN. 



Ultimate skin lesions in man and animals similar. Masked by thick 

 cuticle, pigment, hair, fur, feathers. White, hairless skin, tesions and 

 deranged functions : Maculae, erythema, papules, nodules, blisters, blebs, 

 pustules, boils, carbuncles, scales, crusts, sitfasts, horny growths, erosions, 

 abrasions, chaps, fissures, ulcers, excrescences, cicatrices, neuroses, morbid 

 secretions, changes in glands, hairs, in derma. Scleroderma. Elephanti- 

 asis. Vegetable and animal parasites. 



In cutaneous diseases in man and animals the actual lesions 

 are largely of the same nature, yet in the animal covered with 

 hair, fur or feathers, and with the cuticle deeply pigmented, the. 

 diagnosis of the different affections becomes much more difficult. 

 On white-skinned animals and on parts with little or no hair, the- 

 identification of the different forms is usually possible. The fol- 

 lowing list may serve to indicate the nature of the different lesions, 

 but these must not be accepted as indicating distinct diseases, as 

 two or more of these forms often co-exist or succeed each other 

 in the same affection : — 



ist. Maculae : Spots : Discolorations. Examples : Black, 

 melanotic spots in skins of white horses : white spots in dourine, 

 after pustules, etc. , : ecchymosis after contusions, stings, insect 

 bites, etc. : petechial spots in anthrax, rouget, hog cholera, 

 rinderpest, canine distemper, swine plague, scurvy, etc. 



2d. Erythema : Rash : Flush. Congestive redness usually 

 disappearing under pressure. Physiological in blush or glow of 

 exercise, pathological from insolation, friction, deranged innerva- 

 tion, etc. 



3d. Papulae : Papules : Pimples. Small, red, hard, coni- 

 cal elevations, not forming blister nor pustule. Due to exuda- 

 tion and the accumulation of leucocytes at given points, having a 

 local or general cause, (psoriasis, intertrigo, etc.). 



4th. Tuberculae : Nodules. I^arger but still circumscribed 



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