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to the opinion about the circulation of the blood, which was expected to bring in great and general innovations into the whole practice of physic, but has had no such effect. Whether the opinion has not had the luck to be so well believed as proved sense and experience having not well agreed with reason and speculation—or whether the scheme has not been pursued so far as to draw it into practice, or whether it be too fine to be capable of it, like some propositions in the mathematics, how true and demonstrative soever, I will not pretend to determine.’ Again, Sir William goes on to say: ‘There is nothing new in astronomy to vie with the ancients, unless it be the Copernican System, nor in physic, unless Harvey’s circulation of the blood. But whether either of these be modern discoveries, or derived from old fountains, is disputed—nay, it is so too, whether they are true or no, for though reason may seem to favour them more than the contrary opinions, yet sense can very hardly allow them, and to satisfy mankind both these must concur. But if they are true, yet these two great discoveries have made no change in the conclusions of astronomy nor in the practice of physic, and so have been of little use to the
