The nation's only government owned and operated still began its bubbly summer production of corn whiskey last weekend almos within tobacco-spitting distance of the presidential retreat Camp David in western Maryland's Catoctin Mountain Park.

The still, with its barrels of corn mash fermenting in the woods nearby, is beside a "sweet-water" creek where settlers and moonshiners have been distilling whiskey legally and illegally since 1734.

The last still on the site, a huge Prohibition affair with 25,000 gallons of mash in huge vats beside it, was destroyed by a raiding party of deputy sheriffs in 1929, when one of the deputies was shot to death in a running gunfight through the woods.

Seven years later the Department of Interior created a 10,000-acre mountain park there and WPA laborers built the country's first Presidential retreat, which Franklin D. Roosevelt called Shangri-La - and President Eisenhower later renamed Camp David, after his grandson.

The nearby still is not a private preserve of the President, however, nor does the Park Service have its own public label whiskey . . . "Park Serivce Best" or "Old Department of Interior." The two or three gallon-a-day production of corn whiskey that steams in the woodland kettle, bubbles up through the thump barrel and drips out of the cooling worm pipe may be delicious, as resident Park Service moonshiner Harry Testermen says, but not after he puts ipecac in it.

The still is an illegal North Carolina Prohibition still captured by federal agents and given to the Park Service for historical purposes.

The "revenuers" of the Treasury Department, who wouldn't let the Smithsonian Institution even demonstrate liquor making at the Mall Folk Life Festivals - a North Carolina still was displayed once but was allowed to distill only water - were not about to allow a government-subsidized still go into the whiskey business, according to local Park Service spokesman George Berklacy.

Ipecac, a strong natural emetic or purgative from the roots of a South American shrub, long a popular home remedy, is added to the brew to make it unpalatable. It succeeds admirably, says Testerman, a Tennessee native and retired local hardware store owner. Nobody sneaks down to the Blue Blazes still in the moonlight to steal "this happy juice," he says.

The various stills that operated here legally until Prohibition came in 1919 - as long as the 1791 excise tax was paid - were called Blue Blazes because of a natural gas leak from nearby rock fissures, Testerman says.

The still is one of the more popular attractions at Catoctin, the popular and far flung outpost of the Park Service's National Capital Parks. The park attracted 575,000 visitors last year, more than the Park Service's spectacular Great Falls parks, not counting the thousands of school children who troop up there all year for week-long outdoor education camps.

Since 1973, every sixth grader in Washington's public school system has spent a week at Catoctin's camp, Round Meadow, under a pilot project funded by the Department of Health, Education and Welfare. They stay in lodges built by the Civilian Conservation Corps in the 1930s, which were used for several years by the Marines who patrolled Camp David and in the 1960s by the Job Corps. This summer about 100 youths employed under the Youth Conservation Corps will stay in the lodges and work on the park's trails and buildings.

Several outloads of District children eavorted happily around the park last Friday, at the end of a five-day stay. For many it was their first time away from home alone and the first camp of any kind they had attended.

"It was nice, I met a lot of new friends, played tennis and studied nature and arts and all that . . . and it was my first time away from home by myself," said Jenifer Richardson, a sixth grader at Malcolm X Elementary School in Southeast Washington.

Two other environmental-studies camps in the park are used by Baltimore and several Maryland county school systems, with the Park Service suppluing the camp site and the schools providing the instructors and supplies.

Half of the park was given to Maryland in 1954, and now is called Cunningham Falls State Park, though visitors to Catoctin treat the two parks as one and park literature is published jointly by the U.S. and Maryland Park Services. A 78-foot waterfall, a lake, good rock climbing and scenic views, camping, some of Maryland's best trout fishing and the Park Service's arts and crafts center are among the attractions.

The heavily-wooded hills themselves - as well as the whiskey still and Camp David - are also major draws, particularly in autumn when the brilliant fall foliage jams the park with visitors.

The number of visitors to a park one and one-half hours drive from Washington marks the success of one of President Roosevelt's pet projects. In 1936 the hills had been denuded of trees, clear-cut to feed nearby iron furnaces and lumber mills; the federal government bought the land as the Catoctin Recreational Demonstration Area, to prove the feasibility of creating a part out of worn out lands