Macrobius, Saturnalia 1.20.4-5
nam Apollodorus in libris quibus titulus est περὶ θεῶν scribit quod Aesculapius divinationibus et auguriis praesit. nec mirum: siquidem medicinae atque divinationum consociatae sunt disciplinae. nam medicus vel commoda vel incommoda in corpore futura praenoscit, sicut ait Hippocrates oportere medicum dicere de aegroto τά τε παρεόντα καὶ τὰ προγεγονότα καὶ τὰ μέλλοντα ἔσεσθαι, id est ‘quae sint, quae fuerint, quae mox ventura sequentur’, quod congruit divinationibus quae sciunt τά τ᾽ ἔοντα τά τ᾽ ἐσσόμενα πρό τ᾽ ἐόντα.
Apollodorus writes (in his books whose title is On the Gods) that Aesculapius is in charge of divinations and auguries. And this is not surprising, since the disciplines of medicine and divination are connected; for a doctor knows in advance both the good and bad things which will occur in the body, just as Hippocrates says that a doctor ought to speak, concerning a sick person, of ‘the present things and the things which existed before and the things which shall be’ – that is, ‘What is, what has been, and what soon will come and follow’ – which is in agreement with prophecies, which know ‘What is, what will be, and what was before’.