""An Only Sister"" is a novel written by Henriette De Witt and published in 1873. The story revolves around the life of a young girl named Mary, who is the only daughter of a wealthy family. Mary is adored by her parents, but she longs for a sibling to share her life with. Her wish is granted when her parents adopt a young boy named Willie. Mary is thrilled to have a brother, but soon realizes that her parents' attention is now divided between her...