(Chapter 1) Footnote 1:

Vesalius’ terrestre (terreum 1555) is the Latin equivalent of Gk. gew=dej, as in Aristotle De partibus animalium 663b.29: “The bony part in the bodies of animals is earthy.” The idea that earth is a component of bone was attributed by Aristotle ( De anima 410a) to the Sicilian philosopher Empedocles (493-433 BC), who held that bone was two parts water, two earth, and four fire. Vesalius’ immediate source is probably Galen De ossibus ad tirones 2.733.3: “The bones are the hardest and driest parts of the animal, and, as one might say, the most earthy;” cf. De elementis ex Hippocrate 1.4.53.11: “But just as in the cosmos you show me the earthy body of stone, so in animals I will show you the type to which bones and cartilage and hair belong.” All citations of Greek sources are according to the Thesaurus Linguae Graecae and its Canon of Greek Authors and Works, Third Edition, ed. by L. Berkowitz and K. A. Squitier (New York: Oxford, 1990).