436 



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 deeper 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 economy of the animal through the evaporation of their watery 

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

 as beside regulating the animal heat and excreting impurities, it influ- 

 ences largely the internal organs through the intimate sympathy main- 

 tained 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 inflammation are the most markea 

 features, varying according to the grade or form into (o), congestion 

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

 (h) iniiammation with red pointed elevations but no blisters {jpapules) ; 

 ic) iniiammation with fine conical elevations, each surmounted by a 

 minute blister (resic/e); (^), inflammation with a similar eruption 

 but with larger blisters, like half a pea and upwards {huUc^)', {e) 

 inflammation with a similar eruption but with a small sack of white 

 creamy pus on the summit of each elevation {pustides); (/), the for- 

 mation of pustules implicating the superficial layer of the true skin, 

 a small portion of which dies and is thrown off as a slough or core 

 ihoils)- (a), the formation of round, nodular, transient swellings in 

 the true skin {tnUrcles), and (7^), the excessive production of scales or 

 dandruff (scaly or squamous afl^ections). _ 



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

 heat, tenderness, etc. {neurosis). 



(.3) Diseased growths, as warts, callosities, horny growths, cancer, 



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



(5) Diseases connected with a specific poison-horsepox, erysipelas, 

 anthrax, farcy or cutaneous glanders, etc. 



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



CONGESTION— RED EFFLORESCENCE— 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 

 tchy 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 

 when it becomes aggravated it may merge in part or m whole into a 

 papular, vesicular, or pustular eruption. 



Erythema may arise from a variety of c«...s, and ^^f'^J^^ 

 in accordance witli its most prominent cause. Thus the clulling or 



