satisfied with the perpetual
disagreement which is found in the opinions of the principal masters and
ancient authors of this science, which is only known to men well read,
without discovering to the vulgar the controversies and various judgments
which they still nourish and continue amongst themselves.

Will you have one example of the ancient controversy in physic?
Herophilus lodges the original cause of all diseases in the humours;
Erasistratus, in the blood of the arteries; Asclepiades, in the invisible
atoms of the pores; Alcmaeon, in the exuberance or defect of our bodily
strength; Diocles, in the inequality of the elements of which the body is
composed, and in the quality of the air we breathe; Strato, in the
abundance, crudity, and corruption of the nourishment we take; and
Hippocrates lodges it in the spirits. There is a certain friend of
theirs,--[Celsus, Preface to the First Book.]--whom they know better
than I, who declares upon this subject, "that the most important science
in practice amongst us, as that which is intrusted with our health and
conservation, is, by ill luck, the most uncertain, the most perplexed,
and agitated with the greatest mutations." There is no great danger in
our mistaking the height of the sun, or the fraction of some astronomical
supputation; but here, where our whole being is concerned, 'tis not
wisdom to abandon ourselves to the mercy of the agitation of so many
contrary winds.

Before the Peloponnesian war there was no great talk of this science.
Hippocrates brought it into repute; whatever he established, Chrysippus
overthrew; after that, Erasistratus, Aristotle's grandson, overthrew what
Chrysippus had written; after these, the Empirics started up, who took a
quite contrary way to the ancients in the management of this art; when
the credit of these began a little to decay, Herophilus set another sort
of practice on foot, which Asclepiades in turn stood up against, and
overthrew; then, in their turn, the opinions first of Themiso, and then
of Musa, and after that those of Vectius Valens, a physician famous
through the intelligence he had with Messalina, came in vogue; the empire
of physic in Nero's time was established in Thessalus, who abolished and
condemned all that had been held till his time; this man's doctrine was
refuted by Crinas of Marseilles, who first brought all medicinal
operations under the Ephemerides and motions of the stars, and reduced
eating, sleeping, a