The '20s and '30s were a time of lilting language and looser laws concerning the miraculous medicinal ministrations of various tonics sold from the back of the wagon. It was a great time for fast-talking pitchmen like Fred Foster Bloodgood, who will revive the era of old-fashioned medicine shows at the Washington Ethical Society Auditorium on Friday night.

Bloodgood was here in 1979 as part of the Smithsonian's Folklife Festival, where a medicine show was created with 14 old-time singers, string-musicians and comedians. It had been a long time between pitches for "Doc Foster's Hospital Tonic" (Bloodgood didn't use his real last name because it sounded a bit too contrived for his line of work). In fact, the 64-year-old native of Madison, Wis., is the last surviving pitchman in America. When the Smithsonian decided to revive the medicine show concept, it had "combed the country and found only two of us," Bloodgood recalled. "Doc Bartok from Florida passed away after appearing once. I guess that makes me the last, though it's not really a joyful thought. I think you could say we're an endangered species."

Bloodgood hadn't done a pitch for 40 years and "didn't know if it would come back. But when they started playing the fiddles, guitars and banjos, it all came back, exactly the same pitch I had done from 1928 to 1940. It was like turning on a switch. I was amazed and stricken with awe that I could remember a 30-minute lecture." The Smithsonian took the show on tour and filmed a documentary; Bloodgood may do some of the narration. Friday he'll be dispensing stories, advice and who knows what else on 16th Street.