"Thus thought I, as by night I read Of the great army of the dead, The trenches cold and damp, The starved and frozen camp,-- The wounded from the battle-plain, In dreary hospitals of pain, The cheerless corridors, The cold and stony floors. Lo! in that house of misery A lady with a lamp I see Pass through the glimmering gloom And flit from room to room. And slow, as in a dream of bliss, The speechless sufferer turns to kiss Her shadow, as it falls Upon the darkening walls."

Source: Henry Wadsworth Longfellow (1871). “The Poetical Works”, p.283