The power of attention fixes the mind on those sensations or impressions of most worth, pushing the others into the background. Past impressions, memory-pictures, linger in the brain, and these, bidden or unbidden, crowd with the others. To know the relation of all these, to distinguish present impressions from memories, realities from dreams,--this is mental sanity. The sane brain performs its appointed task. The mind is clear, the will is strong, the attention persistent, and all is well in the world. But the machinery of the brain may fail. The mind grows confused. It mistakes memories for realities. It loses the power of attention. A fixed idea may take possession of it, or it may be filled by a thousand vagrant impressions, wandering memories, in as many seconds. In this case the response of the muscles becomes uncertain. The acts are governed not by the demands of external conditions but by internal whims. This is a condition of mania or mental irresponsibility. Some phase of mental unsoundness is produced by any of the drugs which affect the nerves, whether stimulants or narcotics. They may help to borrow from our future store of energy, but they borrow at compound interest and never repay the loan. They give an impression of joy, of rest, of activity, without giving the fact; one and all, their function is to force the nervous system to lie. Each indulgence in any of them makes it harder to tell the truth. One and all, their supposed pleasures are followed by reactions, subjective pains as unreal as the joys which they follow. Each of them, if used persistently, brings incapacity, insanity, and death. With each of them use creates appetite. To yield once it is easier to yield again. The harm of some of them is slight. Tea, coffee, beer, claret, in moderate quantities, do but moderate harm, but all of them are without other effect on the nerves save to work them injury. White lies at the best are falsehoods. These are the white lies of physiology. In regard to each of these, the young man must count the cost. Count all the cost and be prepared to pay. The song of Ulrich von Hütten, when he gave his life for religious freedom, is worth applying to all other costly things. He sang:-- "'Ich habe gewagt mit Sinnen Und trage des noch kein Reu.'" "With open eyes have I dared it, and cherish no regret." For all indulgence in wine and coffee and tobacco you will have a bill to pay. Perhaps not a heavy bill. The indulgence may be worth the while, but if so, find out for yourself beforehand whether others have found it so. If you dare, dare with open eyes and cherish no regrets. For regret is the most profitless thing to cherish. There is nothing more distressing than remorse without will. The only hope in the world is to stop, and by the time that the inebriate comes to realize where he is, it is too late to stop.