Sentence:  When the caustic is removed, the <WSD>eschar</WSD> should be punctured for the discharge of the matter, and then dressed with warm emollient poultices... 
Meaning of the word marked with <WSD> tags:  Any hard, dark, commonly flattened or sunken lesion or crust, especially on a burn, abscess, infection, wound; commonly a coagulation of blood or exudations, not necessarily involving dead or necrotic tissue.