“…Both Hirschsprung's disease and acute intermittent porphyria commonly present with constipation. Both at laparotomy and on X-ray each has been shown to have dilated and constricted segments of gut lying adjacently (Calvy & Dundon 1952). Both diseases affect the nervous system: in acute porphyria there is widespread damage to central, peripheral and autonomic nervous systems whereas in Hirschsprung's disease the abnormality is in the autonomic nervous system.…”