Very few men, shaving themselves with an old-fashioned razor, have not, at moments of worry and nervousness, sometimes had the thought of how easy it would be to end existence by drawing the edge of the razor through the important structures in the neck. Some are so affected by this thought that they have to give up shaving themselves. It is a surprise usually to find how otherwise sensible, according to all our ordinary standards, are the individuals who confess to having had annoyance from such thoughts. This illustrates how strongly suggestive the concentration of attention may make an idea, and how much a single idea, when it alone occupies the center of consciousness, tends to work itself out in act, though there is no reason at all for willing in that direction. It is not improbable that in some inexplicable cases of suicide the tendency has actually worked itself out. The expression, "he is a man of one idea," enshrines in popular language the conclusion of psychologists that if a single idea is present in the mind it will surely work itself out. We all know how much men of one idea accomplish. All their powers, physical and mental, are brought to bear on its development. Obstacles that deter other men, conditions that prevent others from daring even to think of doing the thing, seem as nothing to the man {196} of one idea, and in spite of discouragement, and even apparent failure, he often succeeds, notwithstanding obstacles that seemed insurmountable. What is thus true in the practical world is paralleled, for both good and ill, in the microcosm of the human body. A man who has one idea to urge him on is capable of accomplishing things in spite of pains and aches and all sorts of disturbances of function. On the other hand, if the one idea is unfavorable, then, in spite of a heritage of good physical and mental powers, his efficiency is inhibited. If a man gets an idea that there is something the matter with any organ, and concentrates attention on it, he will surely disturb the function of that organ. Just the opposite, however, will happen in case, even with physical defect, he believes that there is nothing the matter, or only something that can be overcome. This is the power of faith as illustrated in the various forms of faith healing, from mental science to Eddyism and the rest. This is the power that the physician must learn to use. In _The Lancet_ for November, 1905, Dr. J. W. Springthorpe, writing on the "Position, Use and Abuse of Mental Therapeutics," said: