154 NON-PARASITIC SKIN DISEASES. 



Cracked Heels and Grease (Eczema of the Pasterns). 



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 which is greatly 

 favoured by wetting the hands. The term " scratches," which was 

 the old English name for cracked heels, is still used in America. 



CAUSES. — Although constitutional causes may predispose to an 

 attack, I do not think they can, of themselves, induce one; for 

 were it so, the inflammation would not be confined within its usual 

 very narrow limits. Moller considers that there is a close con- 

 nection between grease and canker, and that one may develop into 

 the other. Experience amply proves that ordinary cracked heels 

 can be caused by local irritation. If, therefore, we accept (which 

 I am inclined to do) Moller's theory, we must regard, as two distinct 

 diseases, cracked heels and grease ; and that the former cannot be- 

 come developed into the latter, without the presence of a special 

 infective material, which, 1 need hardly say, would have easy access 

 to skin that had already existing cracks and sores. As, however, 

 I am unable to draw a sharp line of demarcation between the re- 

 spective symptoms of cracked heels and grease ; I shall describe 

 them under one heading. 



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

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

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

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

 are thickened portions of the epidermis. The rolls of apparent dirt which a 

 shampooer in a Turkish bath removes from the ^kin 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 Avith 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 batter able to perform this 

 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 imbedded in the true skin. 

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

 thrown into folds, the more plentifully 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 which is to be 

 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, 



