What causes the drying of a neonates cord?

Air/time others . Around the world there have been many patterns used to treat the cord stump after birth.The simplest is to let it dry and occasionally swab it with rubbing alcohol to promote air drying.Some cultures apply breast milk, some apply antibiotics, all seem to have near identical outcomes to doing nothing.Since the cord is no longer hydrated by the fetal waters, it drys.