THE TOY microscope set I got one childhood Christmas almost put me off microscopy for good. Squinting through a cheap plastic eyepiece, manipulating the sloppy focus control with one hand and struggling with the other to position the factory-prepared specimen slides resulted in more neck aches and frustration than reward. So years later when a friend offered me his old professional-quality microscope for a mere fraction of its market value, I hesitated. Besides, I could scarcely see through the dirt-encrusted optics, and the gearing for the traveling stage was so gunked up that it scarcely traveled at all. But a little patience, along with cleaning fluid and grease for the gears, quickly restored this binocular beauty to mint condition. Today I'm convinced it was the best $100 I ever spent. My vintage Spencer has been my constant companion for more than a decade. With it I have poked about inside plant cells, swum abreast of wriggling sperm and gotten delightfully lost inside floating forests of phytoplankton. Unfortunately, no biological specimen can be enjoyed under a microscope for long before natural processes begin to destroy it. Tissues quickly dry out and shrink, and bacteria begin breaking down the delicate structures of life almost immediately after a specimen dies.

Microscopists therefore routinely preserve their treasures before scrutinizing them carefully. The process, called fixation, replaces the water in the specimen's tissues with a chemical that is incompatible with life. The fluid pressure keeps the cells plump while the chemical kills decay-producing bacteria. Cellular proteins are not soluble in many fixing agents, however; they precipitate to form a sort of plaster that sticks to cell walls. This process stiffens the cell wall and can actually increase its index of refraction, making the cell stand out under the microscope, but it ultimately destroys potentially useful information.

When amateur scientist extraordinaire George Schmermund of Vista, Calif., recently brought together his interests in insects and microscopy, he uncovered a wonderful fact. Different tissues within an insect absorb the fixing agent he used at different stages in the fixing process. By observing the specimen throughout fixation, rather than waiting until the process is complete, as microscopists are often taught to do, he found that separate organ systems within the animal became highlighted sequentially. This let Schmermund take the stunning pictures of insect insides that you see here. His technique empowers any amateur microscopist to explore insect interiors in a detail unmatched by any other method I know.

Begin your own fantastic voyage by securing some suitable specimens. Small ants and fleas make ideal subjects. Schmermund kills them by placing them in his freezer for a few hours. His fixing agent is ordinary isopropyl (rubbing) alcohol. Isopropyl alcohol is inexpensive, readily available and easy to handle.

My local drugstore stocks isopropyl alcohol in concentrations of 70 and 91 percent. Buy the highest concentration you can find. For reasons that will become clear in a moment, if you intend to create a permanent library of mounted specimens you'll need to purchase pure (anhydrous) isopropyl alcohol from a chemical supply company. (Note that denatured alcohol is a blend of mostly ethanol and methanol; it is not isopropyl alcohol. Both substances are also fixing agents, but methanol is highly poisonous. If you choose to experiment with denatured alcohol, take appropriate precautions to protect your family and pets.)

To get views like those you see here, you must regularly check the insect while fixing. Transfer the insect to a well slide (a slide with a polished depression to receive the sample) with a drop of fixing solution, rest a slide cover on top, then set sail into uncharted waters. Transfer and position the specimen with laboratory tweezers (available at a laboratory supply store and often at your local swap meet) and an eyedropper.

Unfortunately, neither water nor alcohol mixes with the compounds used to glue your specimen permanently to the slide. So to share your specimen with posterity, you must first replace every trace of both water and alcohol with a solvent that will mix with the glue. The process that removes the alcohol is called clearing. Clearing will make your specimen largely transparent and will destroy much of the contrast created during the fixing stages. You can lock in some permanent contrast by staining your specimen with various commercially available dyes, such as borax carmine or alum cochineal. But no method I know of produces the level of contrast in specific tissues that naturally develops during the fixing process.

Xylene is the clearing agent of choice for the amateur scientist. I recently purchased 32 ounces (a lifetime supply!) for $5 in the paint section of my local hardware store. But watch out: xylene is poisonous, it dissolves plastic on contact, and its fumes can make you quite sick. So be particularly careful to protect yourself and your family and pets. In addition, although water mixes with alcohol and alcohol mixes with xylene, water and xylene do not mix. The water must be completely removed with a final fixing step in 100 percent anhydrous isopropyl alcohol before clearing.

Once the specimen has been soaked in pure alcohol for two hours or more, place it in a solution of equal parts of xylene and anhydrous isopropyl alcohol.Cover your container to keep the xylene from evaporating. Your specimen will probably float at first. Let it soak for an hour or two after it sinks to the bottom and then replace the mixture with pure xylene. Your specimen should become fairly translucent at this stage. Dark patches mark water that was not removed during fixation. These can often be cleared up by returning the specimen to the anhydrous alcohol for several hours and then re-clearing it.

Scientific supply companies sell Canada Balsam and a variety of plastic resins for the permanent mounting of specimens. The resin dissolves in xylene, and so it infuses into the insect's tissues before hardening. To make your final slide, place your cleared specimen in the depression in the well slide, add a drop of resin and gently angle the slide cover down on top, being careful not to trap any air bubbles. Let the resin set before moving the slide.

One final note. Some microscopists have marveled at the striking depth of field visible in Schmermund's handiwork. Here's his secret. These photographs were taken with 35-millimeter film at low magnification and then enlarged in a darkroom. Low magnification means good depth of field.

As a service to amateur scientists everywhere, the Society for Amateur Scientists (SAS) has put together a kit that contains everything you'll need to fix, clear and mount small insects. The kit contains anLydrous isopropyl alcohol, xylene, laboratory tweezers, six well slides, a small killing jar for your freezer, small petri dishes for fixing and clearing, slide covers and mounting resin. Send $54.95 plus $5 shipping to the Society for Amateur Scientists, 5600, Post Road, #114-341, East Greenwich, RI 02818. For telephone orders, call 1-401-823-7800. For information about this and other amateur science projects, check out the SAS's World Wide Web site at http://www.thesphere.com/SAS/ or call 1-401-823-7800.

I gratefully acknowledge informative conversations that I had with George Schmermund.

The Society for Amateur Scientists (SAS) is a nonprofit research and educational organization dedicated to helping people enrich their lives by following their passion to take part in scientific adventures of all kinds.