In some mode or other, we are all of us constantly considering this problem. Pass through the sieves we must, if we would survive. The process seems never-ending. We may be able to select or modify our sieves, hurry our progress or retard it, but we can neither stand still nor turn back. If we cannot or will not fit ourselves to the sieve, or if mankind, by their combined action, cannot or will not fit the sieve to us, then we must be cast out. This casting out, if sudden, we term death; if slow, disease and death. We have habituated ourselves to regard life and health as natural--death and disease as unnatural if premature; but for our mode of thought in the latter case there seems little justification. The process of disintegration that we call disease is wholly natural. The result of two opposing forces is the path of our planet in space; the result of two opposing forces is our life. Let either force gain the ascendancy, and our life goes, or begins to go. Sooner or later, then, we must be rejected from a sieve. But our early rejection and our late rejection are two very different matters. Our sudden rejection or our slow rejection are two very different matters also. Disintegration is always going on, but if we absorb sufficient nutriment to repair the waste adequately, we are in health. If, owing to disease of any part, the waste is more than we can repair, one of the opposing forces has gained the ascendancy, and death has begun. We justly regard this slow death in life as a most terrible fate: we will do anything to avert it. To death itself we may be resigned; to some it is an escape from suffering; by some it is regarded as the entrance to a higher life. But all alike shrink from the prospect of dragging out long years of pain and hopeless misery in the sick-room. And just as we are becoming better acquainted with the causes and prevention of disease in various forms, one form of it has recently spread in our midst to an alarming extent, our ignorance of its nature and origin rendering us powerless against its incursions. Nervous prostration encounters us on all sides. It finds victims in all classes of life. It has come amongst us like a thief in the night. Disease, like any other adversary, finds out the most vulnerable part. The most vulnerable part of our machinery is that about which we are most ignorant. We are lamentably ignorant about our nervous systems; our adversary, repulsed in other quarters, effects an entrance there. It is far more difficult to expel him when once he has made his abode with us, than to fortify the stronghold against him. Prevalent as this particular form of disease is at the present moment, that is not the worst of the evil. It is alarming and disheartening to be told that it is still on the increase; but such is nevertheless the fact.