Our sub-conscious mind seems to be almost independent of our physical life; it works more or less continuously while the conscious mind is working, fooling or sleeping. To continue the loft simile: beneath the machine loft, with its clatter and dust, is a quiet darkened room, in which our sub-conscious mind lives and functions in its own quiet way. Men who know how to use it say that, when their conscious minds become exhausted and have come to an impasse, all they have to do is to open the trapdoor and pass the apparently insoluble problem down into the quiet room below. They then banish the subject from their minds completely, rest, play, or take up some other line of thought, and by and by, in a day or two perhaps, when they are not thinking of it, the problem turns up solved. There is no sense of fatigue or of conscious effort in this process: it is just the old adage of sleeping over a difficulty. Many of the world’s great inventors have, knowingly or sometimes unknowingly, made their great discoveries in this way. Our conscious minds are limited in motive power and always subject to fatigue, but our sub-conscious minds rarely tire and are unlimited in scope and power, for they are a part of our Divine inheritance, a portion of the great undivided spiritual force that moves and governs the universe, that slumbers not nor sleeps. To get into close touch with this power needs persevering practice, but it is clearly of inestimable value. We must not expect a clear and useful response unless we have given concentrated attention to the matter in point; a mass of ill-digested, uncertain data will remain as such; we must be perfectly honest with our _alter ego_; it is of no use trying to take him in. The more often and thoroughly we accustom what we call ourselves and our sub-conscious minds to work together in a friendly way, the better and the quicker will be the response. The above is only a cursory sketch of a profound subject, but will serve to show what great economies can be made in the working of our limited human understandings. The condition of our arteries that we call sclerosis is much more common in the sedentary brain-worker than it is in the outdoor man. We see it rarely in the farmer, the sailor, the labourer, unless it is as the result of habitual intemperance; we see it rarely in the athlete. The average blood-pressure of the indoor worker is certainly higher than that of the open-air worker, even in perfect health.