Cakradatta (Cikitsasangraha) 71.14

71.14

prasṛtaṃ vardhayedūrdhvaṃ dvādaśāṣṭādaśasya tu .
āsaptateridaṃ mānaṃ daśaiva prasṛtāḥ param .. 13 ..

Beyond [that age], one should increase by a prasṛta up to twelve years; for an eighteen-year-old, however, / this measure is ten prasṛtas up to seventy years, which is the maximum. // 13