Footnote 4:

This triple division of the medical arts was attributed in antiquity to the Pythagoreans (Aristoxenus 58 D 1, p. 467, 5 ff. Diels-Kranz; see also Vit. Pyth. 29.163.4ff., 34.244.1 ff.), and is reflected in paragraphs 3-5 of the Hippocratic oath. See Edelstein 1987, p. 21.