I shall put an end to what relates to this part of my subject, by giving an abstract of the justly celebrated advice of Celsus, with respect to the preservation of health. “A man,” says he, “who is blessed with good health, should confine himself to no particular rules, either with respect to regimen or medicine. He ought frequently to diversify his manner of living; to be sometimes in town, sometimes in the country; to hunt, sail, indulge himself in rest, but more frequently to use exercise. He ought to refuse no kind of food that is commonly used, but sometimes to eat more and sometimes less; sometimes to make one at an entertainment, and sometimes to forbear it; to make rather two meals a-day than one, and always to eat heartily, provided he can digest it. He ought neither too eagerly to pursue, nor too scrupulously to avoid, intercourse with the fair sex: pleasures of this kind, rarely indulged, render the body alert and active; but, when too frequently repeated, weak and languid. He should be careful in time of health not to destroy, by excesses of any kind, that vigour of constitution which should support him under sickness.” PART II. OF DISEASES. CHAP. XII. OF THE KNOWLEDGE AND CURE OF DISEASES. The knowledge of diseases does not depend so much upon scientific principles as many imagine. It is chiefly the result of experience and observation. By attending the sick, and carefully observing the various occurrences in diseases, a great degree of accuracy may be acquired, both in distinguishing their symptoms, and in the application of medicines. Hence sensible nurses, and other persons who wait upon the sick, often discover a disease sooner than those who have been bred to physic. We do not however mean to insinuate that a medical education is of no use: it is doubtless of the greatest importance; but it never can supply the place of observation and experience. Every disease may be considered as an assemblage of symptoms, and must be distinguished by those which are most obvious and permanent. Instead therefore of giving a classical arrangement of diseases, according to the systematic method, it will be more suitable, in a performance of this nature, to give a full and accurate description of each particular disease as it occurs; and, where any of the symptoms of one disease have a near resemblance to those of another, to take notice of that circumstance, and at the same time to point out the peculiar or characteristic symptoms by which it may be distinguished. By a due attention to these, the investigation of diseases will be found to be a less difficult matter than most people would at first be ready to imagine. A proper attention to the patient’s age, sex, temper of mind, constitution, and manner of life, will likewise greatly assist, both in the investigation and treatment of diseases.