Sentence:  It used to be the fashion to put a second thick covering or "<WSD>pilch</WSD>" over the napkin to keep the outer clothes from wet; but this is by no means healthy, as it over-heats this part of the body, and is often a mere excuse for neglecting the frequent changes that should be made, so that the skin is apt to become sodden, and subsequently sore, from damp heat. 
Meaning of the word marked with <WSD> tags:  a covering put over an infant's diaper to prevent outer clothes from getting wet