"It is a common observation, (and I think has great probability on its side,) that fools, weak or stupid persons, heavy and dull souls, are seldom much troubled with vapours or lowness of spirits. The intellectual faculty, without all manner of doubt, has material and animal organs, by which it mediately works, as well as the animal functions. What they are, and how they operate, as I believe very few know, so it is very little necessary to know them for my present purpose. As a philosophical musician may understand proportions and harmony, and yet never be in a condition to gratify a company with a fine piece of music, without the benefit of sounds from proper organs, so the intellectual operations (as long as the present union between soul and body lasts) can never be performed in the best manner without proper instruments. The works of imagination and memory, of study, thinking, and reflecting, from whatever source the principle on which they depend springs, must necessarily require bodily organs. Some have these organs finer, quicker, more agile, and sensible, and perhaps more numerous than others; brute animals have few or none, at least none that belong to reflection; vegetables certainly none at all. There is no account to be given how a disease, a fall, a blow, a debauch, poisons, violent passions, astral and aerial influences, much application, and the like, should possibly alter or destroy these intellectual operations without this supposition. It is evident, that in nervous distempers, and a great many other bodily diseases, these faculties and their operations are impaired, nay, totally ruined and extinguished to all appearance; and yet, by proper remedies, and after recovery of health, they are restored and brought to their former state. Now, since this present age has made efforts to go beyond former times, in all the arts of ingenuity, invention, study, learning, and all the contemplative and sedentary professions, (I speak only here of our own nation, our own times, and of the better sort, whose chief employments and studies these are,) the organs of these faculties being thereby worn and spoiled, must affect and deaden the whole system, and lay a foundation for the diseases of lowness and weakness. Add to this, that those who are likeliest to excel and apply in this manner, are most capable and most in hazard of following that way of life which I have mentioned, as the likeliest to produce these diseases. Great wits are generally great epicures, at least, men of taste. And the bodies and constitutions of one generation are still more corrupt, infirm, and diseased, than those of the former, as they advance in time and the use of the causes assigned."