Fourth sense: natural as having its cause in nature; the body's temperament and the tree of life
He adds that what has its cause in nature itself is called natural. "In this way too," he says, "immortality was in a manner natural to the first man. For it rested on the excellent balance of the human body as its inner cause and on the tree of life as its outer cause, and each of these was a natural cause of that effect."
Latin
XVII. Rursum addit naturale dici id quod in ipsa natura causam habet. Et etiam, inquit, hoc pacto immortalitas fuit primo homini quodammodo naturalis. Nam in optima humani corporis temperie tanquam interna causa, & in ligno vitae tanquam externa causa (quarum utraque ad illum effectum naturalis erat) immortalitas consistebat.