They should first set before their minds the nature of the practice, and the evils to which it exposes. But here comes the difficulty. What _are_ its legitimate evils? They know indeed that the written laws of God condemn it; but the punishment which those laws threaten, appears to be remote and uncertain. Or if not, they are apt to regard it as the punishment of _excess_, merely. _They_, prudent souls, would not, for the world, plunge into excess. Besides, '_they_ injure none but _themselves_,' they tell us. Would it were true that they injured none but _themselves_! Would there were no generations yet unborn to suffer by inheriting feeble constitutions, or actual disease, from their progenitors! Suppose, however, they really injured nobody but themselves. Have they a right to do even this? They will not maintain, for one moment, that they have a right to take away their own life. By what right, then, do they allow themselves to shorten it, or diminish its happiness while it lasts? Here the question recurs again: _Does_ solitary gratification actually shorten life, or diminish its happiness? The very fact that the laws of God forbid it, is an affirmative answer to this question. For nothing is more obvious than that all other vices which that law condemns, stand in the way of our present happiness, as well as the happiness of futurity. Is this alone an exception to the general rule? But I need not make my appeal to this kind of authority. You rely on human testimony. You believe a thousand things which yourselves never saw or heard. _Why_ do you believe them, _except_ upon testimony--I mean given either verbally, or, what is the same thing, in books? Now if the accumulated testimony of medical writers from the days of Galen, and Celsus, and Hippocrates, to the present hour, could have any weight with you, it would settle the point at once. I have collected, briefly, the results of medical testimony on this subject, in the next chapter; but if you will take my statements for the present, I will assure you that I _have before me_ documents enough to fill half a volume like this, from those who have studied deeply these subjects, whose united language is, that the practice in question, indulged in _any degree_, is destructive to body and mind; and that although, in vigorous young men, no striking evil may for some time appear, yet the punishment can no more be _evaded_, except by early death, than the motion of the earth can be hindered. And all this, too, without taking into consideration the terrors of a judgment to come.