[610] Which is that form (rūpa), external, that is not the ear base (sotāyatana) … not the nose base (ghānāyatana) … not the tongue base (jivhāyatana) … not the body base (kāyāyatana)? The form base (rūpāyatana) … edible nutriment (kabaḷiṅkāra āhāra) — this is that form, external, that is not the body base.
Which is that form, internal, that is the body base? That body which is sensitivity (pasāda) derived from the four primary elements (mahābhūta) … this, too, is an "empty village" — this is that form, internal, that is the body base.
Which is that form, internal, that is not the body base? The eye base (cakkhāyatana) … the tongue base — this is that form, internal, that is not the body base.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.