XXI. 



DISEASES OF THE SKIN. 



ERYTHEMA. 



This consists of an inflammation of the outer layer of the 

 dermis or skin, produced Ly mild irritating agents, such as rubi- 

 facents, or from inflammation depending upon constitutional dis- 

 turbance. When present, there is a redness of the skin, with 

 heat, swelling, and irritation. The causes are cold and heat 

 operating alternately on the skin, friction, pressure, heredity, 

 debility, plethora, and poverty. We have the acute and chronic 



forms. The chronic 

 fonn is seen in long- 

 standing cracked 

 heels. 



CRACKED HEELS 



Is very common 

 among race horses of 

 both classes, and is 

 most frequently seen 

 in the hind limbs. It 

 is produced in a 

 variety of ways, as 

 washing the heels and 

 not drying them prop- 

 erly, filthy stables, irregular exercise. A fruitful cause is per- 

 spiration collecting in the heels and in the flexures. Heat and 

 cold will produce it. Washing the legs and not properly drying 

 them is no doubt the chief cause. 



Symptoms. — At first there will be a slightly reddened appear- 

 ance of the heel. This is followed by a crack or fissure. The 



(284) 



• ^ ''^*f:n%i^y^j^s^^^^^- 



Fig. 76 — Cracked Heels to the Extent 

 of Sloughing. 



