THE INORDINATE appetite to mushrooms is considered to be a French disease," clucked an anonymous author in 1670, a statement which still holds some truth in it. During that era, at the instigation of Louis XIV, mushrooms were cultivated in volume for the first time in history, in the limestone caves of Paris. Today, cultivated mushrooms in France are often called "champignons de Paris".

The first allure of mushrooms may have come not only from their deliciousness, but also because of the hint of a voluptuous poison, which, before they were completely understood, often left a question as to whether a diner would keel over after a marvelous feast of freshly-gathered fungi. Colorful visions induced by some mushrooms have also lent an air of intrigue to them.

The poisonous effects of mushrooms (or toadstools, as the dangerous varieties are popularly known) have been blamed for the deaths of Emperor Tiberilus, Pope Clement VII, King Charles VI of France and many other important personages. This was one culinary privilege of the high-born which commoners were probably happy to forego. But, as hedonists have always known, pleasure is often heightened by an element of danger.

My first introduction to modern mushroom farming left me completely enchanted. After entering the eerie silence of a darkened mushroom-growing house, called a "double," and peering at the thousands of Pennsylvania white against the mahogany dirt through a thin shaft of light from the door, I could have been convinced that fairies were going to appear shortly to harvest the gleaming jewels.

My imagination was brought back to earth, so to speak, when the grower intruded with the information about what was beneath all of the pristine beauty of the agaricus bispori I observed. "I wouldn't eat a mushroom without washing it," said Mike Pia of the Kaolin Mushroom Farms in Avondale, Pa. "I grow them, and I know what they come from."

Mushrooms are grown in horse manure with the addition of straw, gypsum and some dirt, among other things.

It's not as easy to procure horse manure as it was when mushrooms were first cultivated in the U.S., around te turn of the century, when small farms abounded. Nowadays, the mushroom growers in Chester County, Pa., the largest mushroom growing region in the world, prevail upon the racetracks in the area to sell them all of the horse manure they can spare.

As it turns out, migrant workers wearing miners' helmets, not fairies, are the ones who pick mushrooms. This takes place daily on mushroom farms, often in the wee hours of the morning. Because of the fragile nature of mushrooms, they are shipped immediately. Therefore, the mushrooms you buy today in a market, if they have not been held on the shelf, could have been still growing as little as 24 hours ago.

The quickest way to tell how long it's been since a mushroom was picked is to look at the base of the stem where it was cut: The browner it is, the older it is.

The freshest commercial mushrooms are dry and firm and white, without spots or bruises (mushrooms bruise very easily when handled). An old mushroom has its gills exposed; you can see them in the space between the cap and the stem. It the cap is partially or completely open, the gills should be light in color.

The size of the mushroom is not an indicator of tenderness, but keep in mind that caps are more tender than stems. Those with long stems should be cheaper.

If you are not going to use fresh mushrooms right away, an easy way to preserve them is to freeze them, unwashed, in covered plastic containers. Or blanch for a few minutes, then rinse with cold water. Otherwise, store mushrooms, again unwashed in the refrigerator with plenty of air around them. When mushrooms can't breathe they become slimy.

Although most shoppers aren't aware of it, there is more than one type of cultivated mushroom to choose from in the supermarket. Until recently on the east coast, the white mushroom has been cultivated almost exclusively, however more and more growers are switching to the tan (also called "cream" or "golden" or "brown") strain.

Martin Gaston, speaking for the American Mushroom Institute (AMI), located in Kennett Square, Pa., points out that no marketing distinction is made between the white and tan strains. However, perhaps because the tan mushroom is a little more dense and deteriorates less rapidly when stored, they often have a stronger mushroom flavor. "It tastes better when it looks better," according to Gaston. "The browns are better for stuffing," he added.

When we sauteed the two types of mushrooms in butter and submitted them, without explanation, to a tasting panel of six people, we discovered the tan mushrooms were meatier and had a more concentrated mushroom flavor.

Admittedly, the taste difference between the two cultivated mushrooms is a matter of fine tuning, but to recognize the tan strain, look for a fresh mushroom which has a little wood-stain color to it and an ever-so-slightly flaky cap. Be prepared to not be able to tell them apart. Theoretically, both strains are sold throughout the metropolitan area. a

Another choice is between Specials mushrooms, beautifully white and free from almost all dirt and blemishes. "They look like they're made out of white velvet," says Michael Canon of the U.S. Department of Agriculture. Fancy mushrooms are smaller and can be dirtier.

The reason for their immaculate appearance is that Specials are washed before they get to market, usually in a solution with sodium bisulfite and sodium chloride. The purpose of this is to clean up the mushrooms for the most demanding customers, such as restaurants and posh supermarkets.

"If my mushrooms aren't white enough, often I'll get them back from the chef," says Dave Yevzeroff of Hudson Brothers Produce, who sells mushrooms to a great many fine Washington restaurants.

Since washing mushrooms shortens their shelf life by two to three days, the sodium bisulfite is added to attempt to counteract this; the sodium chloride ostensibly retards browning.

The consumer takes a bath along with the washed mushrooms, says John Pia of Kaolin. Mushrooms soak up 20 percent of their weight in the wash water, and we end up paying more than if we bought them "dry" and washed them ourselves.

Although the Europeans have no edge on cultivated mushrooms, they are way ahead when it comes to widespread knowledge and use of the scores of edible wild mushrooms. Mushroom appreciation in Europe is so advanced that, for example, entire stores in the appropriate regions of France are devoted exclusively to wild mushrooms. And muschrooming is a favorite hobby for many, especially Eastern European family groups.

The dangers of eating wild mushrooms are exaggerated, but they exist for those who are careless or ill-informed.

"Hunting mushrooms is risky," agrees Jack Czarnecki of Joe's restaurant in Reading, Pa. "A little knowledge is more dangerous than none at all."

He knows what he is talking about, for he is the third generation chef-proprietor of a unique restaurant which specializes in the wild mushrooms picked by his family. Czarnecki's Polish grandfather brought over his love and knowledge of mushrooms from the old country, and today Joe's menu reflects an enormous variety of wild mushrooms in a sophisticated array of international dishes, complemented by an outstanding list of California wines.

In the season, late spring to early fall, the Czarecki family gathers up to 50 types of wild mushrooms and puts up most of them by canning or drying. They are served throughout the year in soups, salads, marinated, in quiches, sauces and, most successfully, in the Polish dishes such as Chef's Casserole, a ragout made with pheasant, homemade sausage, veal, flageolets and wild mushrooms.

"I like working with fried mushrooms very much," says Czarnecki, but he warns that reconstituting almost always robs wild mushrooms of their flavor. So after soaking his mushrooms for about an hour in a little salt water, he adds a touch of stock or beef base and heats them a bit. Then the strong mushroom taste is concentrated in the liquid, which should be used in the recipe to heigten flavor. "Most people throw the baby out with the wash," Czarnecki notes. The mushrooms themselves can be used for texture, he adds.

The three best known wild mushrooms are the cepe, the chanterelle and the morel. But there are many other less expensive and less lofty types of wild mushrooms available to perceptive shoppers in the Washington, D.C., area. Fresh

Mikado Grocery, 4709 Wisconsin Ave. NW, has an interesting selection of oriental mushrooms. Among the fresh types:

Tree Mushrooms, about $4.80 per pound. These have a taupe-colored cap and slightly resemble our own commercial mushrooms. Their flavor is similar to commercial but a bit stronger. Recommended.

Japanese Forest Mushrooms, $5.90 per pound. These are the all-around best-tasting fresh mushrooms we found. When washed, they turn black on the outside, which contrasts with the pearly white inside. Eaten raw, they have a slight coconut flavor, but when cooked they are smooth and delicious with a slight bite. They are scrumptious sauteed and eaten alone. Recommended.

Enoki-Dake, $1.15 for a 3.5 ounce package. Now being grown in California, these mushrooms are appearing more frequently in our groceries. Called nameki in Japanese, they look a bit like long bean sprouts with little bulbs on the end. They are best eaten raw in salads or as a garnish for soup or omelettes because they are extremely delicate and tend to become slimy if overcooked. Their flavor is mild and the texture crisp.Recommended. DRIED

Chanterelles, $2.99 per ounce at Hudson Brothers Greengrocers, 3206 Grace St. NW. This is a beautiful mushroom, which puffs up nicely when soaked. When cooked, these chanterelles retain a pleasant crunchy texture. Recommended.

Pfifflerlinge, (German chanterelles), Silva brand, $1.40 per 1/4 ounce at the German Deli, 814 11th St., NW. Recommended.

Morels, $6.99 per ounce at Hudson Brothers. This classy mushroom looks a bit like a sponge with a hollow center, therefore has lots of crevices for sand and dirt to hide in. It's important to wash them carefully. They look beautiful when soaked and produce a strong, delicious amber liquor. Recommended.

Steinpilze, (German yellow boletus),Silva brand, $1.98 for 1/4 ounce at German Deli. Recommended.

Porcini, Bruschi brand, $2.30 for 15 grams at Vace, 3510 Connecticut ave. NW. A species of cepe, these are also gritty and need thorough washing. They have a wild, high flavor and a strong liquor. Recommended.

Japanese dried (unlabeled plastic bag), $1.98 for 3.5 ounces at Mikado. These are tough and rubbery when soaked, with a nice shape and a flavor reminiscent of garlic. Recommended.

"Imported" by Kirch Mushroom Company (sold in fancy groceries in a clear plastic container with white snapon lid), $1.09 per ounce at Bradley Food and Beverage, 6904 Arlington Rd., Bethesda. Wherever they're from, these have a strong, wild flavor and are very gritty. Recommended. CANNED

Chanterelles, Bayerwald brand from West Germany, $6.40 for 4 ounces at Georgetown Coffee, Tea and Spice, 1328 Wisconsin Ave. NW. Best flavor of all canned mushrooms we tried. They taste earthy and authentic and are creamy when cooked. Recommended.

Chanterelles, Basserman brand from West Germany, $6.75 for 3.7 ounces at Wagshal's Delictessen, 4855 Massachusetts Ave. NW. Texture of a domestic commercial mushroom and a light, wild flavor; good cooked. Recommended.

Yellow boletus mushrooms, Alpenkrone from West Germany, $5.25 for 4 ounces at Wagshal's. Rather bland but pleasant. Not recommended.

Champignons de Paris, $1.50 for 4 ounces at Georgetown Coffe, Tea and Spice. The familiar cultivated mushrooms, canned by the French and sold here for a steep price. No different from domestic canned. Not recommended. h

Sunyo Nameko (boiled enoki-dake in acan), $2.83 for 4.5 ounces at Makado. Reminded us of cellophane noodles; much of the flavor and texture of the fresh is gone, but they would be fine in a cooked dish. Recommended.

Straw mushrooms, Dynasty brand, $1.09 for 8 ounces. Smell like a goldfish bowl, but good flavor and texture. Not recommended.

Kinoko Shigure (enoki-dake with soy), $2.69 for 8.4 ounces at Mikado. These are yummy; strong soy flavor. Recommended. FREEZE DRIED

We found two types of freeze-dried coultivated mushrooms.

Wagner's $1.09 for 1/8-ounce at Wagshal's. Plump, white, closely approximates fresh. Recommended.

Blanchaud, $2.65 for 1/5-ounce at Wagshal's. More thinly-sliced and a definite freeze-dried taste. Not recommended. TO WASH OR NOT TO WASH?

This question quickly becomes moot when one discovers what mushrooms come from. It is not little specks of harmless dirt one considers, but horse manure. "The medium that they are grown in is pretty treacherous," warns Michael Canon of the U.S. Department of Agriculture.

Despite this, chefs and cooks continue to argue the merits of brushing soil from mushrooms with a brush or a damp cloth versus rinsing them. One argument has it that giving mushrooms a bath makes them absorb too much water and become soggy and brown.

Not so, say Mike and John Pia, mushroom growers from Avondale, Pa. When a mushroom is perfectly fresh and the cap is still closed, it is much less porous than when it becomes older and the gills are exposed. Besides, handling makes mushrooms brown, not water.

These two young men, who have been eating mushrooms much more often than the rest of us for their entire li ves, rinse their mushrooms in a strainer under cold water.

Many prefessional chefs believe the most efficient way to clean mushrooms is to bounce them up and down for a few seconds in a large bowl of cold water; the dirt then falls to the bottom.

"By the way, you don't peel your mushrooms, do you?" scoffed Pias, as if we were poor city slickers who don't know any better. Apparently that classical preparation is as unless as it is outmoded.