The use of tobacco has so much extended itself in the present generation that we are all obliged to make a decision for ourselves on the ancient controversy between its friends and enemies. We cannot form a reasonable opinion about tobacco without bearing in mind that it produces, according to circumstances, one of two entirely distinct and even opposite classes of effects. In certain states of the body it acts as a stimulant, in other states as a narcotic. People who have a dislike to smoking affirm that it stupefies; but this assertion, at least so far as the temporary consequences are concerned, is not supported by experience. Most of the really brilliant conversations that I have listened to have been accompanied by clouds of tobacco-smoke; and a great deal of the best literary composition that is produced by contemporary authors is wrought by men who are actually smoking whilst they work. My own experience is that very moderate smoking acts as a pleasant stimulus upon the brain, whilst it produces a temporary lassitude of the muscular system, not perceptible in times of rest, but an appreciable hindrance in times of muscular exertion. It is better therefore for men who feel these effects from tobacco to avoid it when they are in exercise, and to use it only when the body rests and the mind labors. Pray remember, however, that this is the experience of an exceedingly moderate smoker, who has not yet got himself into the general condition of body which is brought on by a larger indulgence in tobacco. On the other hand, it is evident that men engaged in physical labor find a muscular stimulus in occasional smoking, and not a temporary lassitude. It is probable that the effect varies with individual cases, and is never precisely what our own experience would lead us to imagine. For excessive smokers, it appears to be little more than the tranquillizing of a sort of uneasiness, the continual satisfaction of a continual craving. I have never been able to ascertain that moderate smoking diminished intellectual force; but I have observed in excessive smokers a decided weakening of the will, and a preference for talking about work to the effort of actual labor. The opinions of medical men on this subject are so much at variance that their science only adds to our uncertainty. One doctor tells me that the most moderate smoking is unquestionably injurious, whilst others affirm that it is innocent. Speaking simply from self-observation, I find that in my own case tea and coffee are far more perilous than tobacco.