During World War II, Homer Allison was in training as a rear gunner on a B-29 Superfortress when he read a long poem by James Whitcomb Riley, "The Passing of the Outhouse," on a bulletin board. Something clicked; a collection was born.

In 1976 his stepfather helped by making him a mini-outhouse and naming it "Homer's Retreat." Today, alongside it on a bookcase in the retired Allison's study are, among others, a night-light model, a quilted two-holer with one door, and a kind of music box that activates when you open the door -- and see a seated Santa Claus. An illustrated poster on the wall makes clear what the Great Australian "Dunny" is. Above hang several paintings by artists near and far of objets d'art. A four-volume compendium by Charlie Ross, Meandering Through the Outhouse, featuring pictures, stories, folklore and poems, has been lent out. But there is a paperback whose subtitle only can be repeated here: An environmentally sound approach to a lost art.

In a scrapbook, a younger Allison, who grew up on a Harford County, Md., farm without central plumbing, is pictured by the outhouse (lone star cutout on the side) used by Lyndon Baines Johnson as a boy in Texas. A stamp proposed in 1986 pictures you-know-what. An article deals with an annual outhouse race on skis near Fairbanks, Alaska. And so on.

"Most people don't even think about it," says Allison, who worked in the aviation industry for 37 years. "But we do have to figure out what to do about it, don't we?"

In the woods below Allison's North Indian Head Estates home in Charles County, an aeration lagoon handles sewage from the subdivision. On humid days when the wind blows from the wrong quarter, he says, grimacing, the smell can be pretty rough. But a hookup with the Mattawoman sewer system is due this year -- none too soon, Allison says with a smile, and heads back to his study.