Like Galen, Vesalius rarely refers to medical authorities of his own time by name, and seldom except to criticize. The present caricature could include a memory of Jean Guinter of Andernach (1505-1574), one of Vesalius’ professors at Paris, a strong Galenist whom Vesalius assisted in his public lectures and in the preparation of Institutiones anatomicae (Paris, 1536). See Singer & Rabin 1946 p. xxi, lxi and O’Malley 1964, pp. 50, 54ff. In the interval between 1536 and 1543, Vesalius became so estranged from his Galenist past that his teachers suffered a kind of damnatio memoriae. Likewise Sylvius, who though mentioned cordially in the first edition of the Fabrica, is expunged from the 1555 edition. In this fashion, Vesalius tends to cover the tracks of contemporaries who had influenced his development, and to portray himself as influenced only by ancient sources (including Galen) and direct observation. The metaphor of navigation by nothing more than a manual is from an adage cited by Galen, who compared the study of anatomy from anatomical books to navigation out of a book. See Galen De compositione medicamentorum per genera 13.605.1-4, and cf. Fabrica II ch. 31 uti forsitan aliquis librorum duntaxat ope nautam agens.