When Felix Jr. announced that the city's most historic Tex-Mex restaurant would close its doors for lack of business, he set off a near-riot. People came from hundreds of miles to eat one last meal at the restaurant they grew up in. Families who had been eating there for more than 50 years slipped Polaroids of themselves under the glass tabletops. If the enchiladas at Felix, served in Spanish sauce or bland brown chili gravy, taste absurdly old-fashioned, it's because they're geared toward the Anglo palates of the late 1940s. And according to Geneva Harper, who has worked as a waitress at Felix from the day it opened in 1948, nothing has changed. Except that the Mexican Dinner went for 50 cents back then. So why eat there now? Besides the nostalgia rush, Felix Mexican Restaurant provides a glimpse back to our culinary roots. It is to modern Tex-Mex what a scratchy recording of the Delta blues is to rock and roll.