This book is written primarily for men: and there are therefore other aspects of the life of sex upon which it is necessary to touch, though they are difficult matters to handle. It is well known that large numbers of men in boyhood, either through untutored ignorance of the physiology of their own bodies, or as a result of the corrupt example and teaching of others, become addicted to habits of solitary vice, in which the seed of life within them is deliberately excited, stirred up and wasted, to the sapping of their physical well-being and the defilement of their minds. Habits of self-abuse, when once they are established, are apt to be extremely difficult to break. The minds of their victims are liable to be morbidly obsessed by the physical facts of sex, and their thoughts continually directed into turbid channels. But it is possible by the grace of GOD to conquer, though there may be relapses before the final victory is won. It is important neither on the one hand to belittle the gravity of the evil, nor on the other to grow hopeless and despondent, but to have faith in GOD. It is also a counsel of common sense to distract the mind, so far as possible, in other directions, and to avoid deliberately whatever is likely to prove an occasion or stimulus to this particular form of sin. The battle of purity can only be successfully fought in the region of outward act if the victory is at the same time won in the region of thought and desire. Books and pictures, or trains of thought and imagination, which are either unclean in themselves, or are discovered by experience to be sexually exciting to particular individuals, ought obviously to be avoided by those concerned, and the mind directed towards the contemplation of whatsoever things are true and honest and just and pure and lovely and of good report. In the hour of strong temptation it is often best, instead of trying to meet the assault directly, to change the immediate environment, or in some other way to concentrate the mind: for example, to sit down and read a clean novel until the stress of the obsession is past. Physical cleanliness, plenty of healthy exercise in the open air (it is unfortunate that the circumstances of many men's lives do not give adequate opportunity for this), temperance in food, and especially--in the light of what has been said above--temperance in drink, are all incidentally of value as aids to the maintenance of purity. So also is the avoidance of the habit of lying in bed in a semi-somnolent condition after true sleep has finally departed. A Christian's body is meant to be a temple of the Holy Ghost, and no other spirit, whether of impurity or of sloth, should be allowed to have domination over him.