154 NON-PARASITIC SKIN DISEASES. 



Cracked Heels and Grease {Eczema of the Pastern). 



DEFINITION. — Cracked heels and grease are terms used "to 

 denote an inflamed condition of the skin at the back of the pastern 

 produced by irritation to the part; mild cases being called 

 " cracked heels " ; bad ones " grease " (pustular eczema). The large 

 warty growths which sometimes accompany grease are termed 

 " grapes." Cracked heels are similar to the chapped condition of 

 the hands which often affects persons in cold weather, and is 

 greatly favoured by wetting the hands. The term " scratches " 

 was the old English name for cracked heels, and is still used in 

 America. 



CAUSES. — Although constitutional causes may predispose to an 

 attack, they do not, of themselves, induce one ; for were it so, the 

 inflammation would not be confined within its usual very narrow 

 limits. There is presimiably a close connection between grease and 

 canker, and one may develop into the other. Experience amply 

 proves that ordinary cracked heels can be caused by local irrita- 

 tion. If, therefore, this theory is accepted, cracked heels and 

 grease must be regarded as two distinct diseases. Cracked heels 

 cannot develop into grease without the presence of a special in- 

 fective material, which would have easy access to skin that had 

 already existing cracks and sores. As, however, a sharp line of 

 demarcation, between the respective symptoms of cracked heels 

 and grease, cannot be drawn, they will be described under one 

 heading. 



The true skin is covered by a protecting layer of scarf-skin (the epidermis 

 or cuticle), similar in its nature to horn and hair, and composed of scales of 

 epithelium. The hard corns which come on the hands from rowing and 

 I other kinds of work, and may be cut off without causing any pain, are 

 thickened portions of the epidermis. The rolls of apparent dirt a shampooer 

 in a Turkish bath removes from the skin of the person upon whom he 

 operates, are for the most part (according to the degree of cleanliness of 

 the subject), layers of epithelium. 



The epidermis being unprovided with nerves and blood-vessels is unable 

 of itself to set up any inflammatory action, its duty being to protect the 

 true skin, which forms it. In order to render it the better able to perform 

 thLs work, it is kept, during health, more or less moist with oil which is 

 poured out from the ducts of the oil glands that are embedded in the true 

 skin. The more any particular part of the skin is subject to become bent oi 

 thrown into folds, the more plentifiiUy is it supplied with these oil glands. 

 As the true skin is very sensitive to the action of any external irritant, 

 it follows that causes which tend to weaken the protective action of the 

 epidermis, may give rise to inflammation of the true skin, of which eczema 

 is one form. There . seems but little doubt that the ammonia plentifully 

 found in ill-kept stables, is a fruitful cause of cracked heels and grease. 

 The action of water on the skin renders the scarf-skin soft and pulpy, 

 diminishes its strength by separating the layers which compose it, oije from 



