Great Falls, Dec. 14.— (AP) — Mary Whitson was the true name of the 19-year-old girl known here as Mary Harrighty, who took a fa tal dose of poison Thursday in her room here, officers were told today by an uncle, C. W. Christianson of La Verne, N. D., who came here today to claim the body. The girl, he said, is the daughter of Mr. and Mrs. Louis Whitson of Valley City, N. D. She ran away from home in August and was first located here when she was picked up in a park dressed as a boy. In a film of dust on the mirror of her room, she had written, “I love you, I am leaving.”