434 BUKEAU OF ANIMAL INDUSTRY. 



throw out offensive liquid discharj^es, as in "grease," or produce red, 

 tender fungus growths ("'grapes"). 



The .sweat glands of the horse, like those of man, are composed of 

 simple tubes, which extend down through the cuticle and dermis in a 

 spiral manner, and are coiled into balls in the deejx^r layer of the true 

 skin. In addition to their importance in throwing offensive waste 

 products out of the system, these glands tend to cool the skin, and the 

 entire economj'of the animal through the evaporation of their waterj- 

 secretion. Their activity is therefore a matter of no small moment, 

 as besides regulating the animal heat and excreting impurities, they 

 iiiiluence largeh" the internal organs through the intimate sympathy 

 maintained between them and the skin. 



Diseases of the skin may be conveniently divided, according to their 

 most marked features, into — 



(1) Those in which congestion and inflannnat Ion are the most marked 

 features, varying according to the grade or form into {a) congestion 

 with simple redness, dryness, and heat, but no eruption {erythema)^ 



(b) injlarmnation with red-pointed elevations, but no blisters {paj)ules\) 



(c) infiaimnat'ion with fine conical elevations, each surmounted by a 

 minute blister {vesicle)', (cl) {nfla}nmation with a similar eruption but 

 with larger blisters, like half a pea and upwards (hulla?); (<?) inflamma- 

 tion with a similar eruption, but with a small sac of white creamy pus 

 on the summit of each elevation {pnstules)-, {/) the formation of pus- 

 tules implicating the superficial layer of the true skin, a small portion 

 of which dies and is thrown off as a slough, or "core" {hoils)\ (g) the 

 formation of round, nodular, transient swellings in the true skin 

 {tubercles); and (A) the excessive production of scales, or dandruff', 

 {scaly or squamous affections). 



(2) Diseases in which there are only deranged sensations of itching, 

 heat, tenderness, etc. {neurosis). 



(3) Diseased growths, such as warts, callosities, horny growths, 

 cancer, etc. 



(4) Diseases due to parasites, animal and vegetable. 



(5) Diseases connected with a specific poison, such as horsepox, 

 erysipelas, anthrax, farcy, or cutaneous glanders, etc. 



(6) Physical injuries, like wounds, burns, scalds, etc. 



CONGESTION (red EFFLORESCENCE, OI^ ERYTHEMA). 



This is a congested or slightly inflamed condition of the skin, unat- 

 tended by any eruption. The part is slightly swollen, hot, tender or 

 itchy, and dry, and if the skin is white there is redness. The redness 

 is effaced by pressure, but reappears instantly when the pressure is 

 removed. Unless in transient cases the hairs are liable to be shed. 

 It may be looked on as the first stage of inflammation, and therefore 



