There is an endless supply of stories about sleepwalkers . People have been said to climb on roofs, solve mathematical problems, write music, walk through windows, and do murder in their sleep. In Revere, Massachusetts, a hundred policemen searched for a lost boy who left his home in his sleep and woke up five hours later on a strange sofa in a strange living room, with no idea how he had got there. At the University of Lowa, a student was reported to have the habit of getting up in the middle of the night and walking three-quarters of a mile to the Lowa River. He would take a swim and then go back to his room to bed. An American expert on sleep claims  that he has never seen a sleepwalker. He is said to know more about sleep than any other living man, and during the last thirty-five years he has lost a lot of sleep watching people sleep. He says, "Of course, I know that there are sleepwalkers because I have read about them in the newspapers. But none of my sleepers ever walked, and if I were to advertise for sleepwalkers for an experiment, I doubt whether I would get many takers ." Sleepwalking, however, is a scientific reality. It is one of those strange things that sometimes look quite fantastic . Doctors say that sleepwalking is much more common than is generally supposed. Many sleepwalkers do not try to find help and their sleepwalking is never recorded. There was a college student who got into the habit of   _  .
walking three-quarters of a mile every day getting up in the middle of the night and walking down to the river swimming in the Lowa River before going to bed walking about before he went to bed