Complex sentence: Calcidius commentary on Plato's Timaeus praises Alcmaeon (as well as Callisthenes and Herophilus), about their work on the nature of the, mentions Alcmaeon excised an animal eye to study the optical nerve.
Split into simpler sentences: Calcidius commentary on Plato's Timaeus praises Alcmaeon (as well as Callisthenes and Herophilus), about their work on the nature of the eye. He mentions Alcmaeon excised an animal eye to study the optical nerve.