This matter is not often understood by the community generally; especially by the young. I might tell them of the diseased eyesight; the ulcerated--perhaps deformed--nose and ears, and neck; the discoloration, decay, and loss of teeth; the destruction of the palate, and the fearful inroads of disease on many other soft parts of the body; besides the softening and ulceration and decay and eventual destruction of the bones; and to crown all, the awfully offensive breath and perspiration; and I might entreat them to abstain, in the fear of God, from those abuses of the constitution which not unfrequently bring down upon them such severe forms of punishment. A thorough knowledge of the human system and the laws to which all organized bodies are subjected, would, in this respect, do much in behalf of mankind; for such would be the change of public sentiment, that the sensual could not hold up their heads so boldly, as they now do, in the face of it. Happy for mankind when the vicious shall be obliged, universally, to pass in review before this enlightened tribunal! Young men ought to study physiology. It is indeed to be regretted that there are so few books on this subject adapted to popular use. But in addition to those recommended at page 346, there are portions of several works which may be read with advantage by the young. Such are some of the more intelligible parts of Richerand's Physiology, as at page 38 of the edition with Dr. Chapman's notes; and of the 'Outlines of Physiology,' and the 'Anatomical Class Book,' two works recently issued in Boston. It must, however, be confessed, that none of these works are sufficiently divested of technicalities, to be well adapted, as a whole, to the general reader. Physiology is one of those fountains at which it is somewhat dangerous to 'taste,' unless we 'drink deep;' on account of the tendency of superficial knowledge to empiricism. Still, I am fully of the opinion that even superficial knowledge, on this long neglected topic, is less dangerous both to the individual and to the community, than entire ignorance. And after all, the best guides would be PARENTS. When will Heaven confer such favors upon us? When will parents become parents indeed? When will one father or mother in a hundred, exercise the true parental prerogative, and point out to those whom God has given them, as circumstances may from time to time demand, the most dangerous rocks and whirlpools to which, in the voyage of life, they are exposed? When will every thing else be done for the young rather than that which ought never to be left undone?