FALL IS hog butchering time.

So big deal, you say. What can that possibly have to do with me? I don't live on a farm. What it has to do with you is that fresh pork is about to start arriving at the meat counters, and this is the time of year to buy pork cheaply. Many people who are eating more natural food have stopped buying meat with nitrates added, and bacon and ham are two of the more common meats included in their boycott. Another one is sausage.

What you need is a farmer with some extra meat to sell. Don't know any farmers? Well, you could always put an ad in the paper. Or, as one city-dweller I know did on a beautiful fall Saturday, drive to the country (come now . . . there's still country near you!) and put up 3 x 5 cards in the feed stores: "WANTED PIG MEAT (cleaned and wrapped) for pork and sausages and bacon. Please call before butchering." Her unusual term for the euphemism, "pork," brought several calls within the week.

Remember, however, if you try this tactic, that farmers are early birds, and feed stores, while they often open as early as 7 a.m., tend to close by noon on Saturdays.

Sausages have been around for over 2,000 years. Considering what a popular food they are, it's remarkable how little most people know about their preparation. Traditionally, sausages were made of miscellaneous trimmings from the freshly butchered pigs, chopped finely, seasoned heavily, stuffed into the intestines of a convienent (dead) animal, smoked or dried, or hung in a spring house, and cooked throughout the winter. Today we have the choice of natural or synthetic casings, and with the convenience of freezers, we can entirely avoid some of the intricacies of preservation. It isn't even necessary to stuff sausages at all; sausage meat can be ground, seasoned and wrapped, a pound to a package, just like hamburger, or formed into patties before freezing.

Traditional sausages grew up in many countries; bologna in Bologna, Italy; frankfurters from Frankfurt, Germany; Genoa Salami in Genoa, Italy; and braunschweiger in Braunschweiger, Germany. Most of the sausages were distinctive because of their spicing, but some became known for ingredients other than meat. Oatmeal was often added to Scottish sausages, cabbage and sausage in Luxemburg, potatoes in Swedish sausage. Even American Indians had a distinctive sausage. Buffalo meat was often dried and combined with dried berries into a patty which was then fried.

Many of these traditional sausage recipes are still to be found in old books, or in new books which make a point of bringing back old ways. (Such as Carla Emery's Old Fashioned Recipe Book or Yvonne Young Tarr's Up-With-Wholesome, Down-With-Store-Bought Book of Recipes and Household Formulas. And many of them call for the addition of saltpeter, or potassium nitrate. Meat processors have substituted sodium nitrite for potassium nitrite, and now use lower percentage of the preservative.

Nitrites have been added to meats about to be cured in order to intensify and hold the red color, which is considered appealing by most customers. Its use has been supported by meat packers on the grounds that it prevents the growth of botulinum , a claim that is opposed by many who point out that while nitrites have been shown to limit bacterial growth, in the amounts used commerically they are no more than a color preserver. Nitrite itself can be a carcinogen (cancer-producing agent). The double bind produced by the danger of botulism and the danger of cancer makes the whole subject very confusing. Since there seems to be a clear danger of nitrite poisoning from overcured sausages, many writers are now recommending, as I do, that home sausage makers avoid the use of nitrate entirely.

Vitamin C, in the form of ascorbic acid, works reasonably well as a color preserver, and salt does a good job restricting bacterial growth. As a safety measure, treat all home-cured sausages as fresh meat, and freeze them or can using a pressure canner. Never taste raw sausage meat (there is a danger of trichinosis as well as botulism); always cook a small portion to taste when seasoning your batch before stuffing casings. Adjust the seasoning; cook another portion and taste. EARLY AMERICAN BREAKFAST SAUSAGE

Choose meat scraps with no blood, gristle, skin, or bone attached. Aim for about one part fat to two parts meat for the best texture. If you use straight pork, try to get most of the meat from the shoulder; beef chuck is also the right ratio.

For each pound of medium-ground raw pork, add the following: 1 teaspoon salt 1/4 teaspoon thyme 1/4 teaspoon sage 1/8 teaspoon black pepper 1/4 crumbled bay leaf

For best results, mix the spices with a small amount of water first, then sprinkle over the meat as you blend it with your hands. Leave plenty of room for mixing in your container -- a plastic dishpan works well for several pounds of sausage.

Stuff into links or wrap tightly in plastic wrap, and refrigerate for 24 to 48 hours to blend flavors. Freeze until ready to cook.