Since these points have often been, and still continue to be disputed with great warmth by physicians in large volumes, ’tis proper to add some reflections, that may seem to come the nearest to the truth, and which neither slavishly follow either of these opinions, nor are too remote from both, but lie, as it were, in the middle, betwixt these opposite extremes; which those, that inquire after truth without partiality, may find to be the surest method for directing the judgment in most warm controversies, as well as in this now before us. For, with regard to the causes of health or diseases, in what manner the air, or food, is either conveyed or distributed, the philosophers themselves do not attain to an absolute certainty; they only make probable conjectures. Now, when there is no certain knowledge of a thing, a mere opinion about it cannot discover a sure remedy. And it must be owned, that nothing is of greater use, even to the rational method of curing, than experience. Altho’ then many things are taken into the study of arts, which do not, properly speaking, belong to the arts themselves, yet they may greatly improve them by quickening the genius of the artist; wherefore the contemplation of nature, though it cannot make a man a physician, yet may render him fitter for the practice of medicine. Indeed, it is very probable, that both Hippocrates and Erasistratus, and all the others, who were not content with treating fevers and ulcers, but examined in some measure into the nature of things, tho’ they did not by such study become physicians, yet became more able physicians by that means. And medicine itself requires the help of reason, if not always amongst the occult causes, or the natural actions, yet often; for it is a conjectural art; and not only conjecture in many cases, but even experience is found not consistent with its rules. And sometimes neither fever, nor appetite, nor sleep, follow their usual antecedents in the regular course. A new distemper sometimes, though very seldom, appears; that such a case never happens is manifestly false; for, in our own time, a certain lady, from a quantity of flesh(11) falling down from her private parts, and growing dry, expired in a few hours; so that the most celebrated physicians neither found out the genus of the distemper, nor any remedy for it. I suppose the reason they forbore to attempt any thing was, that none of them was willing to run a risk upon his own conjecture only in a person of her quality, for fear he should be thought to have killed, if he did not save her; yet it is probable that some one, without that regard to the opinion of the world, might have contrived something, which upon trial would have succeeded. Nor is a similitude always serviceable in this kind of practice; and where it is, this properly belongs to the rational part, to consider amidst a number of similar kinds, both of diseases and remedies, what particular medicine ought to be preferred. When such an incident