Between 3 and 4 cm of the distal segments of the duodenum (denoted from the gizzard to the pancreatic and gallbladder ducts), jejunum (from the pancreatic ducts to Meckel's diverticulum) and ileum (Meckel's diverticulum to the ileo-cecal junction) were dissected and rinsed carefully with 10% formaldehyde before being submersed in 10% formaldehyde.