Skin Diseases. 265 



4. Parasitic diseases, — -vegetable and animal. 



5. Diseases connected with a specific poison — different 

 forms of variola (pox) — measles — scarlatiaa — erysipelas 

 — malignant pustule, etc. 



6. Wounds. Bums. Scalds. 



General causes. These are exceedingly varied. Many 

 cases are the result of simple local irritation, as chafing, 

 radiating heat, cold and wet, chemical and mechanical irri- 

 tants, or the presence on the skiu of parasitic plants or 

 animals. A large class is due, however, to disorders of 

 internal organs with which the skia is in sympathy, or 

 that have failed to transform or throw off elements that 

 prove cutaneous irritants by their presence in the blood, 

 or when being excreted abnormally through the skin. 

 Disorder of the liver, stomach, bowels, kidneys and lungs, 

 are especially apt to act in this way. Sometimes skin 

 disease is a mere symptom of general iU-health. 



General treatment. The first object is to discover and 

 remove the cause ; then if the disease is of an inflamma- 

 tory nature and acute, soothing agents may be applied to 

 the irritated skin — fomentations with tepid water, oxide 

 of zinc powder or ointment, starch, lycopodium, spermaceti 

 and almond-oil, solutions of sugar of lead, sulphate of zinc, 

 or carboKc acid, collodion, etc. Give internally cooling lax- 

 atives (sulphate of soda, tartrates or citrates of soda or 

 potash,) and diuretics (acetate of potassa or ammonia, 

 carbonate of potassa or soda). In weak states tonics are 

 often wanted whereas in plethoric subjects depletion is 

 equally essential. A cool, clean, airy stable and cleanli- 

 ness of the skin are all-important. 



If the disease is not so recent or the acute symptoms 

 have been subdued, a more stimulating class of local ap- 

 plications are in order : ointments of iodine, sulphur, 

 mercury, nitrate of mercury, tar, oil of tar, oil of turpen- 

 tine, oil of cade, etc., may be used. Supersedents too 

 may be given internally : sulphur, antimony, arsenic, mer- 

 cury, Dunovan's solution, are examples. 

 23 



