Sentence:  But just when she seemed to have sunk into some depravity of peasanthood she would disappear and come down bathed , brushed , and taking breaths of air , and even with her broken nails her hands would come to rest on a table or a leaf with a thoughtless delicacy , a grace of history , so to speak , and for an <WSD>instant</WSD> one saw how ferociously proud she was and adamant on certain questions of personal value . 
Meaning of the word marked with <WSD> tags:  a very short time (as the time it takes the eye to blink or the heart to beat)