Isidore, Etymologies 4.13
Some people ask why the art of Medicine is not grouped among the other liberal arts. It is because they all contain singular causes, but medicine contains the causes of all. For doctors ought to know Grammar, so that they can understand or explain what they read. Similarly, they must know Rhetoric, so that they have the power to define what they are doing with true arguments. Indeed, they must know Dialectic for applying their reason to investigating and caring for the causes of diseases. Similarly, they must know Arithmetic on account of the number of hours in the accessions and periods of the day. Not otherwise is the knowledge of Geometry necessary because of the qualities of regions and the sites of various places, in which the doctor must teach what each person ought to observe. Further, Music will not be unfamiliar to doctors, for there are many things which we may read about its effects in sick people. We read of David that he snatched Saul from an unclean spirit with the art of musical modulation. The doctor Asclepiades, too, restored a certain man suffering from frenzy to his earlier state of health through symphonic music. Finally, the doctor will also have some knowledge of Astronomy, through which may be contemplated the relation of the stars and the changes of the seasons. For just as a certain doctor says, our bodies are changed with their qualities. It is for this reason that medicine is called a second Philosophy – for each of these disciplines claims the whole person for itself. For just as the soul is cared for by Philosophy, so is the body cared for by Medicine.
XIII. DE INITIO MEDICINAE. Quaeritur a quibusdam quare inter ceteras liberales disciplinas Medicinae ars non contineatur. Propterea, quia illae singulares continent causas, ista vero omnium. Nam et Grammaticam medicus scire debet, ut intellegere vel exponere possit quae legit. Similiter et Rhetoricam, ut veracibus argumentis valeat definire quae tractat. Necnon et Dialecticam propter infirmitatum causas ratione adhibita perscrutandas atque curandas. Sic et Arithmeticam propter numerum horarum in accessionibus et periodis dierum. Non aliter et Geometriam propter qualitates regionum et locorum situs, in quibus doceat quid quisque observare oporteat. Porro Musica incognita illi non erit, nam multa sunt quae in aegris hominibus per hanc disciplinam facta leguntur; sicut de David legitur, qui ab spiritu inmundo Saulem arte modulationis eripuit. Asclepiades quoque medicus phreneticum quendam per symphoniam pristinae sanitati restituit. Postremo et Astronomiam notam habebit, per quam contempletur rationem astrorum et mutationem temporum. Nam sicut ait quidam medicorum, cum ipsorum qualitatibus et nostra corpora commutantur. Hinc est quod Medicina secunda Philosophia dicitur. Vtraque enim disciplina totum hominem sibi vindicat. Nam sicut per illam anima, ita per hanc corpus curatur.