The most important general remedy for over-prolonged mental occupation with a single subject, is some outdoor sport or form of exercise that requires all the attention. Horseback exercise is particularly valuable; boating, especially where the man has charge of the boat himself and where he has to have his wits about him, and the various sports. It is particularly important that men should not be alone during the taking of their exercise and diversion of mind. Above all, human interests take a man outside of himself and keep him from disturbing his mental equipoise by too much devotion to a single subject. CHAPTER VII DISTANT MENTAL INFLUENCE There is a very general impression that it is possible, at least under certain circumstances, for one human mind to influence another at a distance without any of the ordinary known means of communication. Many people have had the experience of thinking about a friend whom they have not seen for a long while, and shortly after meeting him. Sometimes it is found that the friend was making up his mind to bring about the meeting just about the time that the thought of him came. Many have had the experience of writing a letter and having it cross in the mails with another from their correspondent, evidently written within a few hours, though there had perhaps been no communication for weeks or months before. There are people who insist that they can, by concentrating the mind and fixing their eyes on the head of a {141} person some distance in front of them in a theater, or a railway car, cause the person to turn around. There are others who say that by thinking strongly of some person in a distant part of a large room, that person can be made to think of them. In general, there are many persons who are quite sure that there is evidence enough to indicate the possibility of distant mental influence, or, as it has come to be called learnedly, telepathy.