Again, people are apt to suppose that no injury is done to their health, because they are not sensible of the wound at the moment; but this also is a notion which we must class among vulgar errors. It is a matter of demonstration, not merely of hypothesis, that we may sustain most grievous injury of which we are not instantly sensible; nay, that so long a time may elapse after the impression has been imparted, that we become unable to trace the effect to its cause; and yet the relation of cause and effect stands sure, however ignorant or unconscious we may be of it. As an illustration of this position, I shall mention a case which came under my own observation. I was once acquainted with a gentleman, who at eighty years of age was what would be called a stout, healthy old fellow. He was certainly of a most robust constitution, and had never addicted himself to any habit “calculated to shorten life,” as they say at the Insurance Offices, saving and excepting that of taking snuff. Well, it has been said to me, “See how your anti-nicotian theory is set at defiance by this hearty old fellow. If tobacco be a slow poison, it must be, as was said of tea, very slow indeed, or how should we have such an exemplary octogenarian as this, ‘o’er all its ills victorious?’ He has been taking snuff all his life, and yet, you perceive, is nothing the worse for it.” Now, I did not perceive any such thing, but was well aware that the contrary was the case. I was of opinion, and am now fully convinced of the fact, that he suffered extremely, nay, intensely, from the habit, without himself or others being at all aware of it. I do not speak of a nose and face perpetually begrimed with snuff--of a waistcoat and inexpressibles embrowned and powdered all over with it--of the expenditure of pocket-handkerchiefs, and waste of time in nose-blowing--everlasting sneezing and coughing, &c.: such matters are mere trifles in the estimate of your professed snuff-takers; but I do speak of an habitual depression of spirits, and frequently an access of the most miserable melancholy, to which this gentleman was subject, and which I attribute to his inveterate habit of snuff-taking, and to no other cause. He would complain bitterly of his wretchedness on those occasions, and ascribe it to the skyey influences--the humidity of our climate, the fogs, and I know not what besides; but it was nothing but “the snuff.” Such intelligence would have doubtless been very unwelcome; for this very snuff--this actual _fons et origo malorum_, ay, “more snuff”--was his most favourite remedy and consolation under these distressing visitations! So much for our ignorance of causes. The late Doctor Adam Clarke was a great enemy to the tobacco leaf, and published a strong paper in condemnation of it. He takes high ground upon the subject.