Gram negative bacterial (Salmonella 3,10:r:- ) outer membrane vesicles (OMVs) and 'invasosomal' periplasmic organelles (PO) observed in vivo in experimental infection of chicken ileum. POs are proposed to be 'blown off' as OMVs (diameter 80- 90nm) in analogy of soap bubbles from a bubble-tube consisting of four or more type III secretion injectisomal complexes, riveting the bacterial outer and inner membrane together during OMV release.