Cut salt pork in one-fourth inch cubes and try out in a frying pan; add onion, and cook until yellow. Pare and cut potatoes in one-half inch cubes, parboil five minutes. Add to onion, with corn and water; cover and cook twenty minutes or until potatoes are soft. Melt butter in a sauce-pan, add flour, stir to a smooth paste, pour some of the milk on slowly, stirring constantly. Combine mixtures; add crumbs and seasonings. Serve for dinner in cups or in small "nappies."