Finer adjustment, clearer and more delicate accommodation or reconciliation of impulses in any one field tends to promote it in others. A step in mathematical accomplishment, other things being equal, facilitates the acquisition of a new turn in ski-ing. Other things are rarely equal it should perhaps be remarked. If this is true even of such special narrowly restricted impulses as are involved in a scientific technique, it is far more evident when the major, the most widespread systems, those active in our responses to human beings and to the exigences of existence, are engaged. There is abundant evidence that removal of confusion in one sphere of activity tends to be favourable to its removal elsewhere. The ease with which a trained mind approaches a new subject is the plainest example, but equally a person whose ordinary emotional experience is clear, controlled and coherent, is the least likely to be thrown into confusion by an unheard-of predicament. Complications sometimes obscure this effect: a mathematician approaching psychology may attempt to apply methods which are inappropriate, and the sanest people may prove stupid in their dealings with individuals of other races. The specialist, either intellectual or moral, who is helpless outside his own narrow field is a familiar figure in inferior comedy. But what would have to be shown before the principle is invalidated is that, granted equal specialisation, the successful specialist is not better fitted for life in general than his unsuccessful _confrère_. Few people, however, will dispute the assertion that transference of ability frequently occurs although the mode by which it comes about may be obscure. When very widespread and very fundamental impulses are implicated, where attitudes constantly taken up in ordinary life are aroused, this transference effect may be very marked. Everybody knows the feeling of freedom, of relief, of increased competence and sanity, that follows any reading in which more than usual order and coherence has been given to our responses. We seem to feel that our command of life, our insight into it and our discrimination of its possibilities, is enhanced, even for situations having little or nothing to do with the subject of the reading. It may be a chapter of _Gösta Berling_ or of _The ABC of Atoms_, the close of the _Vanity of Human Wishes_, or the opening of _Harry Richmond_; whatever the differences the refreshment is the same. And conversely everybody knows the diminution of energy, the bafflement, the sense of helplessness, which an ill-written, crude, or muddled book, or a badly acted play, will produce, unless the critical task of diagnosis is able to restore equanimity and composure.