But, notwithstanding the infinite beauty, the magazine of excellencies and perfections, that appertains to the human body, the mind claims, and justly claims, an undoubted superiority. I am not going into an enumeration of the various faculties and endowments of the mind of man, as I have done of his body. The latter was necessary for my purpose. Before I proceeded to consider the ascendancy of mind, the dominion and loftiness it is accustomed to assert, it appeared but just to recollect what was the nature and value of its subject and its slave. By the mind we understand that within us which feels and thinks, the seat of sensation and reason. Where it resides we cannot tell, nor can authoritatively pronounce, as the apostle says, relatively to a particular phenomenon, "whether it is in the body, or out of the body." Be it however where or what it may, it is this which constitutes the great essence of, and gives value to, our existence; and all the wonders of our microcosm would without it be a form only, destined immediately to perish, and of no greater account than as a clod of the valley. It was an important remark, suggested to me many years ago by an eminent physiologer and anatomist, that, when I find my attention called to any particular part or member of my body, I may be morally sure that there is something amiss in the processes of that part or member. As long as the whole economy of the frame goes on well and without interruption, our attention is not called to it. The intellectual man is like a disembodied spirit. He is almost in the state of the dervise in the Arabian Nights, who had the power of darting his soul into the unanimated body of another, human or brute, while he left his own body in the condition of an insensible carcase, till it should be revivified by the same or some other spirit. When I am, as it is vulgarly understood, in a state of motion, I use my limbs as the implements of my will. When, in a quiescent state of the body, I continue to think, to reflect and to reason, I use, it may be, the substance of the brain as the implement of my thinking, reflecting and reasoning; though of this in fact we know nothing. We have every reason to believe that the mind cannot subsist without the body; at least we must be very different creatures from what we are at present, when that shall take place. For a man to think, agreeably and with serenity, he must be in some degree of health. The corpus sanum is no less indispensible than the mens sana. We must eat, and drink, and sleep. We must have a reasonably good appetite and digestion, and a fitting temperature, neither too hot nor cold. It is desirable that we should have air and exercise. But this is instrumental merely. All these things are negatives, conditions without which we cannot think to the best purpose, but which lend no active assistance to our thinking.