(Chapter 39) Footnote 5:

Vesalius’ marginal note says “Quite often elsewhere, but mostly in Book 3 of De anatomicis administrationibus,” perhaps referring to a comment in the 2nd chapter about the removal of skin prior to dissection of a limb: “The work needs great precision and calls for one who really wants to know and does not mind taking trouble.” (2.351.14f.,tr. Singer 1956, p. 64).