A visit to Washington's Dolls House & Toy Museum is an excursion into Victorian nostalgia, with the added charm of the world of miniatures.

The owner, Flora Gill Jacobs -- a District native whose seven published works about the history and mystery of dollhouses include standard references for the collector and children's books -- fell into her field when she was browsing through an antique barn in New Jersey.

The mansard-roofed "South Jersey house" she found there had once been a handsome example of mid-19th century Victorian. Cobweb-covered, with shattered windows, it suggested a haunted house and inspired her to write The Doll House Mystery.

One thing led to another. In the 1965 edition of her History of Dolls' Houses,she confessed that the collection of three antiques she had mentioned in the 1953 first edition had grown to 40 houses, plus many separate rooms, stables, gardens, shops and kitchens.

Now there are more than a hundred houses and uncounted related items. When asked how many, she answers softly, "lots."

She kept the collection in her home until 1975, when too little space and too many requests from people who wanted to see it led her to open the museum at 5236 44th Street NW. Although a dollhouse inch equals a real-world foot, there's still only room to show about half what she has; she jokes that she could fill the Pension Building.

The exquisitely detailed houses are furnished with miniature antiques and authentic period wallpapers. There's an elegant Mexican mansion from Puebla, built around 1890 and remodeled in the 1920's so that it would seem appropriate for the sleek 1922 limousine parked in its driveway. One can walk by "Bliss Street," a collection of antique houses by Bliss of Rhode Island, or go to the English toy theater, by Pollack, which has sets, paper "characters" and candle footlights. There's a German kitchen complete with an "eismachine" that makes real ice cream. For the "window shopper" there are millinery shops, a Swiss toy shop (which inspired another book) and a delightful general store that offers a ceramic fish in a net bag. There are all kinds of schoolrooms that may make modern students and teachers glad they're modern.

In many of these Victorian houses there's a definite sense of "Upstairs/Downstairs" life, with full staffs of maids, cooks and a butler to attend to the family's care.

In some cases the "architects" of the houses are known. Madame St. Quentin's House (decorated with particularly interesting examples of early wallpaper and decoupage) was built by her estate carpenter in England. It took him from 1856 to 1858. A much simpler "pre-fab" was created for Elma Zimmerman in 1895. Her father used New York ingenuity and a Quaker Oats box as his inspiration.

The museum's 1982 anniversary acquisition is a "mystery mansion": Not even F.A.O. Schwartz has a clue as to who the maker may have been although its New York store is believed to have been where Annie Pickney Watt's family purchased this house more than 80 years ago.

The museum is also enlivened by a collection of antique games and toys, including a baseball game of 1880, "Teddy Roosevelt on Safari," a Civil War-inspired blockade- running game, and Reed's Capitol of 1884, with a handle to crank and bring into view scenes of the Capitol and White House as well as pictures of presidents from Washington to Chester A. Arthur. There's also a small but very fine collection of antique dolls on display, plus a shop where you can buy miniature works of contemporary craftsmen, from Monteith bowls to hand-blown glass. MINATURE MASTERPIECES

The Washington Dolls' House & Toy Museum is open 10 to 5 Tuesday through Saturday and Sundays from noon to 5. Admission is $2 for adults, $1 for children under 14. 5236 44th Street NW (near Lord & Taylor and Nieman-Marcus). 244-0024.