528 DISEASES OF THE SKIN. 



iotense degree of erythema. The cutaneous surfaces which are 

 deprived of integument are particularly sensitive to the influence 

 of solar rays as well as to various irritations ; they are manifestly 

 predisposed to gangrenous dermatitis. Regions which are covered 

 with white hair must necessarily be most frequently affected by it. 



Moulds may determine it in certain cases (trifoliosis, lupinosis). 

 Tainted vetches, green fodder which is covered with blight and 

 rust (Urysibe), and also plant-lice. 



"Gangrenous leg grease" is undoubtedly due to infectious pro- 

 cesses or to causes of the same nature as grease, but acting in a 

 more energetic way (very intense cold, etc.). 



Symptoms. Gangrenous dermatitis starts with symptoms of 

 erythema or of eczema. Tumefaction increases rapidly, the skin 

 cracks, becomes creviced or necrosed upon a more or less extended 

 surface. Sometimes the mortification is limited to the superficial 

 layer of the integument, at other times it affects its whole thick- 

 ness. In the first case the skin presents on its surface dried, 

 tanned blotches ; in the other the sphacelated islands are dis- 

 tinctly defined, then eliminated by suppuration (formation of a 

 disjunctive furrow). The loss of substance is regularly compen- 

 i^ated by a granulation of its walls, but sometimes it is complicated 

 with abscesses, detachments, and fistulse. 



Treatment. In the beginning it is proper to cover the diseased 

 region with lead ointment (plumbo-tannic salve) ^ or carbolated oil, 

 carbolated salve, iodoform or cresol salve, cresol liniment, or cresol- 

 ated water, etc. Later, when the skin is mortified, we must, by 

 means of a bistoury or scissors, remove the necrosed parts and 

 then apply an antiseptic dressing to the wound. 



BULLOUS DERMATITIS: PEMPHIGUS. 



Bullous dermatitis is characterized by the development of more 

 voluminous vesicles than those of eczema, by bullœ, which may 

 attain the size of a hen's egg. 



Etiology. Nothing certain is known concerning the causes of 



^ The formula of this preparation is as follows : 



Acetate of lead 



Tannic acid 



Lard 



20 grammes. 

 10 " 

 70 



— N. D. T. 



