It has been a question much debated, whether, and how far the writings of the ancient physicians are of service to direct our practice in the cure of diseases; but without repeating what has been already said on this point, I imagine their usefulness may be inferred from this single consideration, that the mechanism of the human body being always and every where the same, a faithful history of diseases must necessarily be one of the surest guides to the application of proper remedies. Moreover, if the diagnostics and prognostics be of the greatest moment in physic, and are only to be collected from long and accurate observation, then the records left us by the ancients, who were so assiduous in their observations, so clear and exact in their descriptions, must be allowed to contain a valuable treasure of medical knowledge. We have seen, in the present age, many learned physicians, who, though they readily admit the improvements of the moderns, nevertheless apply themselves with great industry to the study of the ancients; and indeed, to say nothing of the superiority of some of the ancients in stile and composition, as a matter of taste, I think it can hardly be denied, that a man, capable of making proper allowances for the variations in respect of climate and manner of living, may receive great benefit from the materials left us by these ingenious writers of antiquity, and find many hints, which, pursued with diligence, and applied with caution, may both correct and enlarge his practice. Celsus is justly esteemed one of the most valuable amongst the ancients. He is so often quoted, with approbation, by our best writers in physic, and so much admired by the learned world for propriety, ease, and elegance, that it is a needless attempt in these days to draw his character. However, he is so little mentioned by the ancients, that our curiosity cannot be gratified with any particulars of his life; nor can we even determine what was his profession, if it does not appear from his writings. Quintilian often mentions a treatise of his upon rhetoric, which though he hardly ever quotes, but where he differs from him, he allows to be composed with accuracy. But whatever he thought of his oratory, he gives an honourable testimony to the extent of his learning. For to persuade his student of eloquence to make himself master of all the sciences, after mentioning the greatest geniuses that ever appeared in Greece or Rome, as Homer, Plato, Aristotle, Cato the censor, Varro, and Cicero, he adds, “Why should I name any more instances? when even Cornelius Celsus, a man of a moderate share of genius, has not only composed treatises on all these arts, but has also left precepts of the military art, agriculture, and medicine. The bare attempt requires us to believe he understood all these subjects: but to give perfection to so great a work is a difficult task, to which no man was ever found equal[A].” [A] Fab. Quintilian, lib. xii. c. 11.