Wet Preservation

At its core, wet preservation halts the natural process of decay. Living tissue is composed largely of water and organic compounds that decompose rapidly after death. The goal of preservation is to stabilize this tissue—first by fixing the structure in place, and then by creating a chemical environment where bacteria and fungi cannot thrive.

This is achieved in two major phases:

1. Fixation, using formalin (a dilute solution of formaldehyde gas in water).Formalin binds to proteins in cells, cross-linking them into stable structures.This prevents autolysis (self-digestion) and microbial decay, essentially “locking” the specimen in time.
2. Long-term preservation, using isopropyl alcohol or ethanol as a gentle, enduring preservative.Alcohol dehydrates tissue, discouraging microbial growth while maintaining transparency.Over time, it also leaches pigment, lending the specimen its characteristic soft tones of cream, amber, and pale rose—a quiet alchemy of biology and chemistry.

A few humble instruments will help you on your way:

Chemicals:

• Formalin (10% neutral buffered solution) – Used for fixation. Typically made by diluting 37–40% formaldehyde in water and buffering to neutral pH.
• Isopropyl or Ethyl Alcohol (50–70%) – For gradual transition and long-term storage.
• Distilled Water – For rinsing specimens after fixation to remove excess formalin.

Containers:

• Glass Jars or Bottles with Airtight Seals – Preferably borosilicate or archival-quality glass to prevent leakage and degradation.
• Labels – Waterproof labels or archival tags for specimen identification, date, and preservation medium.

Tools and Equipment:

• Gloves – Nitrile or latex to protect skin from formalin and alcohol.
• Eye Protection – Safety goggles or glasses to prevent splashes.
• Ventilated Workspace – Fume hood or well-ventilated area to avoid inhaling toxic fumes.
• Tweezers, Forceps, and Scissors – For careful positioning, trimming, and handling of specimens.
• Measuring Cylinders or Graduated Containers – For accurate preparation of chemical solutions.
• Soft Brushes or Pipettes – For gentle cleaning and positioning of delicate specimens.
• Absorbent Paper Towels – For blotting excess fluid during handling.

Optional Artistic and Display Items:

• Specimen Stands or Supports – To position specimens naturally inside the jar.
• Decorative Backing or Lighting – For aesthetic display while maintaining scientific clarity.
• Patience (the most important tool of all)

Whimsical note: With these materials in hand, the practitioner becomes both scientist and curator—carefully balancing precision with a quiet reverence for the living forms now preserved in liquid memory.

The journey of a specimen into eternal suspension begins long before any chemical touches it. Preparation is both a practical and mindful stage: selecting, cleaning, and arranging the specimen ensures the highest quality preservation while honoring its natural form.

Specimen Selection

• Choose specimens that are ethically sourced. This may include animals or plants that are naturally deceased, responsibly donated, or legally acquired from licensed suppliers. Avoid at all costs harming living creatures solely for collection.
• Smaller specimens are generally easier to preserve: fish, amphibians, reptiles, small mammals, invertebrates, and delicate plant structures respond best to wet preservation. Larger specimens may require dissection, injection of preservatives into internal cavities, or partial fixation techniques.
• Inspect your specimen for damage, decay, or parasites. Only healthy, intact specimens will yield optimal results.

Cleaning and Rinsing

• Gently rinse the specimen with clean or distilled water to remove dirt, sand, or external debris. Use soft brushes or pipettes for delicate surfaces.
• For aquatic or semi-aquatic specimens, remove mucus, algae, or slime to prevent clouding of fluids during preservation.
• Pat the specimen dry carefully with absorbent paper towels, taking care not to compress or distort soft tissues.

Dissection and Positioning (Optional for Medium and Large Specimens)

• Small specimens (under ~3 inches) rarely require dissection; formalin penetrates naturally.
• Medium specimens (3–6 inches) may need small slits or incisions in body cavities for proper internal fixation.
• Large specimens (over 6 inches) often require extensive preparation, including cavity openings and, sometimes, direct injections of formalin into internal organs.
• Position limbs, wings, tails, or leaves before fixation; tissues stiffen during the process, making adjustments afterward difficult.
• Use soft supports (toothpicks, cotton, or foam) to maintain delicate structures.

Mindful Observation

• Take a moment to observe the specimen’s natural form, curves, and textures. Consider how it will appear suspended in fluid—the subtle bend of a tail, the delicate spread of petals, the gentle curl of a wing.
• Document any distinctive features or notes about color, pattern, or anatomy. Accurate observation enhances both scientific and aesthetic appreciation.

Whimsical note: Preparation is the quiet conversation with the specimen before it enters preservation—a respectful introduction, acknowledging the life that was and carefully planning the form it will take in its liquid home. This step blends science and artistry, setting the stage for successful fixation and display.

Fixation is the step where the specimen’s tissues are stabilized, halting decay and preserving delicate structures for study or display. Formalin, typically used as a 10% neutral buffered solution, is the standard fixative because it cross-links proteins, “locking” tissues in place while preventing autolysis and microbial growth. Think of it as a gentle but firm pause button on the biological clock, preserving the specimen in its natural form.

When Dissection is Necessary

Not all specimens are equal in size or complexity, and sometimes minor dissection is required to ensure proper fixation:

• Small specimens (fish, amphibians, insects, or small mammals under ~3 inches) are usually simple: the preservative can penetrate all tissues without intervention.
• Medium specimens (3–6 inches) may require small slits or incisions in the body cavity to allow the formalin to reach internal organs. This ensures that the specimen is uniformly fixed and prevents decomposition in hidden areas.
• Large specimens (over 6 inches or dense-bodied animals) often require more extensive preparation:Carefully open body cavities to allow formalin to reach internal tissues.In some cases, inject formalin into major organs or cavities to accelerate internal fixation.Position limbs, wings, or tails before fixation, as tissues will stiffen and resist repositioning after formalin treatment.

Plain-English analogy: Small creatures are like sponges—soaking them in formalin is enough. Medium animals need a few channels opened so the chemical can seep in, and large specimens are like dense loaves of bread—sometimes you have to poke, inject, or cut a few holes to let the “preservative glaze” reach the center.

Small Specimens

• Examples: insects, small fish, amphibians, tiny mammals (under ~3 inches).
• Fixation Method: Full immersion in 10% neutral buffered formalin is typically sufficient.
• Dissection: Rarely needed; formalin penetrates all tissues naturally.
• Time: Usually 2–3 days.
• Tissue Outcome: Slightly firm, retaining natural shape and flexibility.

Whimsical note: Small specimens are like delicate sponges—the formalin soaks in quickly, pausing their biology without altering their form.

Medium Specimens

• Examples: larger fish, reptiles, birds, or small mammals (3–6 inches).
• Fixation Method: Submerge completely in formalin, but consider small incisions or slits in body cavities to allow internal tissues to fully absorb the preservative.
• Time: Typically 5–7 days, depending on tissue density.
• Tissue Outcome: Firm, with internal organs stabilized; some minor stiffness occurs.

Whimsical note: Medium specimens need gentle guidance—think of creating channels so the chemical can reach every hidden fold and cavity, ensuring nothing is left behind.

Large Specimens

• Examples: larger mammals, birds, or dense-bodied reptiles (over 6 inches).
• Fixation Method: Full immersion is necessary, but additional preparation is often required:Open body cavities for proper internal fixation.In some cases, inject formalin directly into organs or dense tissues.Carefully position limbs, tails, or wings before fixation; tissues will stiffen during treatment.
• Time: Up to 2 weeks, depending on size and tissue density.
• Tissue Outcome: Stiffer overall; internal organs require careful preparation to preserve fine details.

Whimsical note: Large specimens are like dense loaves of bread—without thoughtful openings and guidance, the fixative cannot reach the core. Proper care ensures the specimen enters its liquid home fully intact, with every curve and structure preserved.

Whimsical note: Fixation is like tucking your specimen into a chemical sleeping bag. Small ones curl up naturally; medium ones need a gentle adjustment to fit snugly; large ones require careful folding and padding so every curve and fold is preserved in their final slumber.

Practical Tips for All Sizes

1. Always ensure full submersion in formalin; partial coverage can lead to decay.
2. Neutral buffered formalin prevents discoloration and excessive hardening.
3. Rinse thoroughly in water after fixation to remove residual formaldehyde before alcohol storage.
4. Observe and document unique features—patterns, colors, or textures—for research or display purposes.
5. Submerge Completely – Ensure the entire specimen is covered. Partial exposure leaves tissues vulnerable.
6. Use Neutral Buffered Formalin – A neutral pH prevents discoloration and excessive hardening.
7. Timing –Small specimens: 2–3 daysMedium specimens: 5–7 daysLarge specimens: up to 2 weeks, with gentle rotation to expose all surfaces
8. Rinse After Fixation – 24-hour water rinse removes residual formaldehyde to prevent clouding or tissue damage during alcohol storage.
9. Observe & Record – Note colors, patterns, or features before they fade slightly; this is especially important for research or aesthetic documentation.

Whimsical note: During fixation, proteins form invisible scaffolds, internal organs and delicate structures lock in place, and the specimen transitions from fleeting life into something suspended—a quiet, chemical meditation on form, texture, and time.

After fixation in formalin, your specimen has been chemically stabilized: tissues are firm, proteins are cross-linked, and decomposition has been halted. The next step is long-term preservation in alcohol, which maintains structural integrity, prevents microbial growth, and keeps delicate features visible. This stage is both practical and subtle—requiring patience, precision, and a touch of artistry.

Why Alcohol?

• Alcohol (usually 70% isopropyl or ethyl) works by removing water from cells, creating an environment where bacteria, fungi, and decay-causing enzymes cannot survive.
• It preserves transparency, allowing internal structures like veins, gills, or leaf venation to remain visible.
• Alcohol is gentler than formalin for long-term storage; it doesn’t over-harden tissues and allows specimens to retain some natural flexibility.

Stepwise Transition for Best Results

1. Gradual Soaking

• Begin by transferring the specimen into 50% alcohol for approximately 24 hours.
• This step gradually replaces the water in tissues without shocking them, preventing shrinkage, distortion, or damage.
• After this period, move the specimen to 70% alcohol for long-term storage.

2. Full Submersion

• Ensure the specimen is completely covered by alcohol; even a small air pocket can encourage mold growth or clouding.
• Gently jiggle or reposition the specimen to release trapped air bubbles.

3. Observing Tissue Response

• Small specimens typically adjust quickly, while larger specimens may need longer in the lower concentration before reaching 70%.
• Watch for color changes or excessive stiffening, which may indicate too rapid a transition.

4. Labeling and Documentation

• Record specimen name, collection date, and preservative type.
• Proper documentation ensures scientific value and aids long-term study or display.

Plain-English Analogy

• If formalin is the “invisible glue” that locks tissues in place, alcohol is the protective liquid blanket that keeps the specimen from rotting or shrinking.
• Gradual transition is like acclimating to a new home—too fast, and tissues shrink or distort; slow and gentle, and the specimen settles beautifully in its new environment.

Practical Tips for Alcohol Transition

1. Avoid sudden immersion in high-concentration alcohol. Stepwise transition is key.
2. Full submersion prevents air exposure, which could compromise preservation.
3. Monitor fluid clarity—top off or replace as needed.
4. Keep jars out of direct sunlight and away from temperature extremes to prevent evaporation and discoloration.

Whimsical note: In alcohol, the specimen floats serenely, suspended between time and stillness. Curves, folds, and textures are preserved in liquid clarity, as if paused mid-motion—a quiet celebration of natural form captured for science and curiosity.

Preserving specimens in liquid is a delicate dance between curiosity, science, and care. Formalin and alcohol are powerful tools—they preserve life’s details beautifully—but they are also chemicals that require careful handling. Ensuring personal safety, maintaining a clean workspace, and respecting the specimens themselves are critical to both successful preservation and ethical practice.

Personal Protective Equipment (PPE)

1. Gloves

• Always wear nitrile or latex gloves when handling formalin or alcohol.
• Gloves protect your skin from chemical irritation, staining, and potential absorption of harmful compounds.
• Change gloves if they become damaged, wet, or contaminated.

2. Eye Protection

• Safety goggles or glasses are essential to prevent accidental splashes from reaching your eyes.
• Even small droplets of formalin can cause irritation or damage.

3. Protective Clothing

• Long sleeves and lab coats shield skin and clothing from spills.
• Consider aprons for extra protection when working with larger specimens or during jar transfers.

4. Ventilation

• Work in a fume hood or well-ventilated area.
• Formalin fumes are strong and toxic with prolonged exposure. Alcohol fumes are flammable; avoid open flames and spark-producing equipment.

Safe Handling Practices

1. Chemical Preparation

• Measure chemicals carefully, using graduated cylinders or pipettes to avoid spills.
• Always pour formalin or alcohol slowly, keeping containers stable.

1. Specimen Handling

• Use tweezers, forceps, and soft brushes to position specimens instead of bare hands.
• Avoid compressing or crushing tissues—especially after formalin fixation, when tissues are firm but still delicate.

1. Spill Management

• Keep absorbent paper towels and a designated spill kit nearby.
• Clean spills immediately; formalin should be neutralized if necessary, and alcohol spills should be wiped and ventilated due to flammability.

1. Storage Safety

• Store chemicals in clearly labeled, airtight containers.
• Keep jars away from sunlight, heat sources, and children or pets.
• Alcohol is flammable—never store near open flames.

Health Precautions

• Avoid prolonged skin contact or inhalation of fumes.
• Wash hands thoroughly after handling specimens or chemicals.
• Work in shifts with good airflow and take breaks if working with strong fumes for extended periods.
• If accidental contact occurs: Skin: Rinse thoroughly with water. Eyes: Rinse immediately with plenty of water and seek medical advice. Inhalation: Move to fresh air immediately; seek medical attention if symptoms persist.

Ethical and Practical Considerations

• Always prioritize ethically sourced specimens—never collect living animals solely for preservation.
• Respect the life behind each jar. Preservation is an act of study, appreciation, and artistry, not exploitation.
• Maintain clear documentation of specimens, chemical usage, and safety protocols.

Whimsical note: Safety is both armor and compass. While chemicals and tools wield great power over preservation, careful handling transforms the process from risky experiment into a serene, controlled craft—where curiosity and wonder flourish safely alongside science.

Formalin is a powerful preservative, but it is also toxic and potentially irritating. Proper handling, neutralization, and monitoring are essential to ensure a safe workspace during wet specimen preservation.

Why Neutralize Formalin?

• Formalin is primarily composed of formaldehyde, which is a strong irritant and can be harmful with prolonged exposure.
• Neutralizing residual formalin before disposal or long-term storage reduces odor, limits chemical hazards, and protects your specimens, your workspace, and yourself.
• Neutralization also prevents degradation of jars, labels, and other materials over time.

How to Neutralize Formalin

Dilution for Disposal

• For small amounts of leftover formalin, dilute with copious amounts of water (at least 10:1 water to formalin).
• Pour the diluted solution slowly into a designated chemical waste container. Never pour directly into drains unless local regulations explicitly allow it.

Chemical Neutralization

• Use a neutralizing agent such as sodium bisulfite, sodium metabisulfite, or ammonium bicarbonate.
• Carefully add the neutralizing agent to the formalin solution while stirring gently. A chemical reaction occurs that binds formaldehyde into a safer, less volatile compound.
• Always follow manufacturer instructions for the precise amount and method.

Final Rinse

• After neutralization, rinse all containers thoroughly with water before reuse or disposal.

Formalin Test Kits

• Purpose: Test kits allow you to measure the concentration of formaldehyde in solutions or vapor. This ensures that fixation is complete and that residual formalin levels are safe.
• Recommended Use: Test freshly prepared formalin solutions before use to verify concentration. Periodically monitor the storage jars of specimens to ensure vapor levels are within safe limits. After neutralization, use test kits to confirm that formaldehyde has been reduced to safe levels before disposal.

Plain-English Analogy: Neutralizing formalin is like putting a sleeping bag over a small fire—it doesn’t erase the heat entirely, but it tames it, making the workspace safe while keeping the specimen intact. Test kits are your “thermometers,” letting you know exactly how much chemical energy remains.

Safety Reminders

• Always wear gloves, eye protection, and work in a ventilated area when neutralizing formalin.
• Never mix formalin with other chemicals unless recommended—unintended reactions can be hazardous.
• Document any neutralization and testing for safety and regulatory compliance.

Whimsical note: Neutralizing formalin transforms a potent, invisible preservative into a safer companion, allowing science and artistry to continue without worry. It is the graceful closing act of the fixation stage—a final bow before the specimen moves into its liquid sanctuary.

• Use airtight glass jars or bottles, preferably borosilicate or archival quality.
• Fill completely with 70% alcohol to prevent air exposure.
• Label clearly with specimen name, date, and preservation medium.
• Arrange specimens thoughtfully, considering both scientific study and aesthetic display. Use supports for delicate positioning as needed.

Whimsical note: The jar becomes both archive and reliquary—a vessel where science, memory, and quiet artistry coexist.

Once your specimen has been fixed in formalin and transitioned into alcohol, proper long-term care ensures it remains stable, visually appealing, and scientifically valuable for decades. Even the most carefully preserved specimens can degrade over time if fluid levels, storage conditions, or container integrity are neglected.

Maintaining Fluid Levels

• Always ensure specimens are fully submerged in 70% alcohol. Even a small portion of exposed tissue can dry out, discolor, or become moldy.
• Check fluid levels periodically—at least once every few months—and top off with fresh alcohol as needed to maintain full coverage.
• Avoid overfilling to the point of spilling; a few millimeters of airspace is acceptable, but never let tissues break the surface.

Monitoring Fluid Quality

• Alcohol can evaporate or become contaminated over time.
• Cloudy or discolored fluid indicates it may need replacement. Carefully decant the old alcohol and replace it with fresh 70% alcohol.
• For specimens that release pigments or oils, changing the alcohol periodically preserves clarity and prevents long-term staining.

Container Integrity

• Use airtight glass jars, preferably borosilicate, to prevent leaks and minimize evaporation.
• Ensure lids are secure but not over-tightened, which can crack glass or damage threads.
• Avoid metal lids unless lined; alcohol can corrode unlined metals over time.

Storage Conditions

• Store specimens in a cool, dark location. Direct sunlight can cause fading of tissues and labels, and heat accelerates evaporation.
• Avoid extreme temperatures; freezing can crack jars, while excessive heat can warp labels or degrade alcohol.
• Keep specimens away from children, pets, and high-traffic areas to minimize accidental spills or breakage.

Label Maintenance

• Ensure labels are waterproof or archival quality and remain legible over time.
• Include: specimen name, collection/fixation date, and preservative type.
• Consider maintaining a digital inventory for backup, including photographs and notes on specimen condition.

Periodic Inspection

• Regularly inspect specimens for:Changes in fluid clarity or levelMold or fungal growthCracks or leaks in containersFading or damage to labels
• Early detection of issues allows for simple interventions before serious degradation occurs.

Whimsical Notes

Long-term care is a quiet guardianship. Each jar is a miniature museum, where delicate curves, textures, and patterns float serenely in alcohol. Maintaining proper fluid levels, monitoring container integrity, and checking for clarity ensures that your specimens remain timeless ambassadors of curiosity, ready to inspire wonder and study for decades to come.