62 working hypothesis (see Piccolhomini, Anat. Praelect. ; Romae, 1586, p. 117, and Warner, MS. p. 194). Servetus had speculated, but rightly, as to the lesser circulation ; so had Caesalpinus ; and on Harvey's own showing (p. 15, and ed. Willis, ed. 1766), Realdus Columbus ; and Walter Warner, p. 132 (4394 Birch Coll. MS.), had spoken of the heart, in 1 6 10, as being ' a mere muscle, very strongly and artificially woven, and contrived with omnimodal nerveous fibres, direct, transverse, and oblike, as it were of purpose, for dilata- tion and contraction, according to the fashion of other muscles.' And of the action of the auriculo - ventricular and arterial valves, Harvey himself, nived animd, with untar- nished sincerity, repeatedly (see De Motu, pp. T4, 51, 53, 67, 81), speaks as of some- thing known to all men, ' id omnes norunt ' (p. 44). What then, it might have been triumphantly asked, was there left for Har- vey to discover, when the action of the valves of the heart, its muscular character, and so much else, was already to be found an the writings or teachings of his prede- cessors? To all this we can answer, as
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