CAESALPINUS (CESALPIN0), ANDREAS (1519—1603)  , Italian natural philosopher, was born in Arezzo in Tuscany in 1519 . He studied anatomy and medicine at the university of Pisa, where he took his doctor's degree in 1551, and in 1555 became professor of materia medica and director of the botanical garden . Appointed physician to Pope Clement VIII., he removed in 1592 to Rome, where he died on the 23rd of February 1603 . Caesalpinus was the most distinguished botanist of his time . His work, De Plantis libri xvi . (Florence, 1583), was not only the source from which various subsequent writers, and especially Robert Morison (1620—1683) derived their ideas of botanical arrangement but it was a mine of science to which Linnaeus himself gratefully avowed his obligations . Linnaeus's copy of the book evinces the great assiduity with which he studied it; he laboured throughout to remedy the defect of the want of synonyms, sub-joined his own generic names to nearly every species, and particularly indicated the two remarkable passages where the germination of plants and their sexual distinctions are explained . Caesalpinus was also distinguished as a physiologist, and it has been claimed that he had a clear idea of the circulation of the blood (see HARVEY, WILLIAM) . His other works include Daemonum investigatio peripatetica (1580), Quaestionum medicarum libri ii . (1593), De Metallicis (1596), and Quaestionum peripateticarum libri v . (1571) .