Others there are who are impelled by their own evolutional process to seek the development in themselves of these psychic powers; and to these a word of warning seems necessary, so that at the risk of appearing didactic I must essay the task. To some it may seem unwelcome, to others redundant and supererogatory. But we are dealing with a new stage in evolutional progress--the waking up of new forces in ourselves and the prospective use of a new set of faculties. It is of course open to anybody to experiment blindly, and none will seek to deter them save those who have some knowledge of the attendant dangers, and which knowledge alone can help us to avoid. I should consider the man more fool than hero who, in entire ignorance of mechanics and aeronautics, stepped on board an aeroplane and started the engines running. Even the most skilful in any new field of experiment or research consciously faces certain but unknown dangers. The victims of the aeroplane--brave pioneers of human enterprise and endeavour that they were--fell by lack of knowledge. By lack of knowledge also have the humane efforts of many physicians been cut short at the outset of what might have been a successful career. It was this very lack of knowledge they knew to be the greatest of all dangers, and it was this they had set out to remedy. It is not less dangerous when we begin to pursue a course of psychic development. The ordinary functions of the mind are well within our knowledge and control. There is always the will by which we may police the territory under our jurisdiction and government. It is another matter when we seek to govern a territory whose peculiar features and native laws and customs are entirely unknown to us. It is obvious that here the will-power, if directed at all, is as likely to be effectual for evil as for good. The psychic faculties may indeed be opened up and the unknown region explored, but at fatal cost, it may be, to all that constitutes normal sanity and physical well-being; in which case one may say with Hamlet it be better to "bear those ills we have, than fly to others that we know not of." Some of the conditions imposed upon those who, not being naturally gifted in this direction, would wish to experiment in clairvoyant development, may conveniently be stated and examined in another chapter. CHAPTER VI. OBSTACLES TO CLAIRVOYANCE