1. Introduction.- 2. The receptor hypothesis of protein ingestion.- 3. Macromolecular uptake and transport by the small intestine of the suckling rat.- 4. A preliminary study of the binding of rat and bovine IgG to isolated brush borders from neonatal rat jejunum.- 5. The transmission of high molecular weight break-down products of protein across the gut of suckling and adult rats.- 6. Ferritin uptake by the gut of the adult rat: an immunological and electron microscopic study.- 7. Oral immunization of rats with human serum albumin: interference with intestinal absorption and tolerogenic effect.- 8. Biological functions of antigen-IgA antibody complexes: in vivo and in vitro interference with intestinal absorption and tolerogenic effect.- 9. Antibody response in pigs and calves to antigens from the intestinal lumen and the efficacy of oral immunoprophylaxis against post-weaning enteric infection.- 10. Absorption and endogenous production of immunoglobulins in calves.- 11. Antigen uptake in the small intestine of guinea pigs infected with Trichinella spiralis.- 12. Antibody production in the intestine-associated immune tissues following antigen stimulation in the bowel lumen.- 13. Natural antibodies and the intestinal flora in rodents.- 14. Delayed-hypersensitivity reactions in the small intestine.- 15. Schizophrenia, cereal grains and the gut barrier Coeliac disease as a model.- 16. The chemistry of gliadin.- 17. Urticaria and dietary hypersensitivity.- 18. A review of endotoxin and its absorption from the gut.- 19. Antibody facilitated digestion and the consequences of its failure.- 20. Endopeptidase activity of the small intestine.- 21. The traffic of lymphocytes through the gut of mammals.- 22. Summing up.