Wet Specimens 101: How to Make/Care for Them
What is a Wet Specimen?
Wet specimens are biological specimens that have been preserved and displayed in fluid, most commonly in a jar.
What Materials are Needed to Make and Care for a Wet Specimen?
How are Wet Specimens Made?
Most wet specimens are first injected and soaked in a fixative such as formalin or with high percentage ethanol to prevent decay. After a predetermined amount of time soaking, the specimen is then transferred to distilled water for 24-48 hours. This is called a leeching bath, and serves the purpose of removing excess formalin from the specimen. After leeching, the specimen is transferred to 70% isopropyl alcohol or ethanol for long-term storage. On more delicate specimens you can gradually increase the concentration of alcohol up to 70% to minimize wrinkling or shrinking. It is important to note that formalin is a known carcinogen, so I personally choose not to teach others how/where to get the exact supplies needed to wet preserve specimens. It’s essential to have proper PPE and a safe working space before wet preserving anything. Getting cancer is not worth having a few cool dead things in jars. It is much easier and safer to reach out to someone with experience with wet preserving and ask them to preserve your specimen for you.
What to do When You Receive Your Wet Specimen
If you purchased your wet specimen from our shop it will arrive in two sealed baggies. Before opening the bags, you can safely handle the bag to feel the specimen and see its size. At this point you can begin to prepare your jar for the specimen. If you do not have your jar and alcohol yet, you can safely leave the wet specimen in the bags its shipped in. It’ll be perfectly fine in there for many weeks as long as the inner paper towel stays moist. There is no need to refrigerate or freeze the specimen. Once your jar is ready, you can remove the first bag and use it as a “glove” to get the specimen out and remove the paper towel before placing the specimen in its new jar. Touching the specimen with bare hands is not recommended, as even though the specimens have already been leeched in distilled water to remove excess formalin, there may still be some inside, which we don’t want on your skin. If you aren’t able to use the extra bag as a glove, wearing actual gloves or using forceps is encouraged. Depending on what your specimen is you may find a colored tag attached to it with the name/species of the animal. You can safely remove this tag by snipping it with a pair of nail clippers, wire snips, or a pair of scissors.
What Kind of Jar Should I Use?
The general rule for jars to display wet specimens in is to avoid cork or metal lids. Cork can allow the alcohol to evaporate, and metal will eventually rust. Any glass or plastic container with a good sealing lid will work fine for displaying your wet specimen in.
Once you have your jar picked out, you can fill it partially up with 70% isopropyl alcohol (common rubbing alcohol available at Walmart, the dollar store, etc.) You don’t want to overfill the jar, as when you place your specimen in it will displace some of the alcohol.
What do I do if I Don't Have 70% Alcohol?
Using higher than 70% alcohol runs the risk of shriveling your specimen. If you do not have 70% isopropyl alcohol but have a higher percentage available, you can dilute it with distilled water. Ethanol can also be used in place of isopropyl alcohol- it is most commonly bought as Everclear at a liquor store and is usually 95% (190 Proof). Below is how much water and alcohol to mix together in a Measuring Cup to attain a 70% solution:
If using 91% alcohol, mix 10oz of 91% alcohol with 3oz of distilled water
If using 95% alcohol, mix 10oz of 95% alcohol with 3.57oz of distilled water
If using 99% alcohol, mix 10oz of 99% alcohol with 4.14oz of distilled water
I used 10oz of alcohol for easy conversions, but of course you may need to double/triple/etc. the recipe to achieve the amount of alcohol you need to fill your jar.
How to Best Display a Wet Specimen
Once you have your chosen jar and 70% alcohol ready, it’s time to begin thinking about how exactly you want to display your wet specimen. The process of fixing the specimen in formalin makes the specimens slightly flexible, but overall they are going to stay in the shape they are now. There are still many ways to improve the overall display of your wet specimen so it doesn’t simply look like a dead thing in a jar, some being as simple as putting the jar on top of a LED Stand to illuminate it.
If you ordered one of our Preserved Hearts and don’t want it to simply sit at the bottom of the jar, here’s a neat trick: Take a piece of fishing line and thread it through the top of the heart (if you can’t fit it through one of the vessels simply make a small hole in the top tissue). Once the fishing line is holding the heart up in the alcohol, adjust the height/position by moving the fishing line and then close the jar lid on the line to make the heart look suspended in the alcohol.
If you ordered one of our preserved animal fetuses and want it to look suspended, you can fill the bottom of the jar with clear glass marbles before adding your alcohol and specimen. The marbles should be invisible once the alcohol is added. You can also cut up a clear soda bottle and use the plastic sides to prop up your specimen. If you don’t want your specimen to lean against the glass you can also place glass rods around it. Anything that is clear glass or plastic can be used in the container of alcohol without interfering with the solution and should be invisible once the alcohol is added.
How to Care for Your Wet Specimen Long Term
Wet specimens are typically pretty hardy specimens and can last lifetimes if properly cared for. The most common issue for wet specimens is the liquid evaporating. If your jar isn’t air tight you will experience evaporation. When you notice your liquid evaporating it is imperative that you don’t simply “top off” the jar with more alcohol. It’s important to realize that your ideal solution is 70% alcohol, with the remaining 30% being water. Alcohol evaporates faster than water, so each time you top it off your overall alcohol percentage is lessening. When you see evaporation you need to completely replace the solution with fresh alcohol.
It is also not uncommon for your alcohol solution to become slightly cloudy or discolored- most often a yellow color. This is most likely more leeching taking place over time. It won’t harm your specimen to leave it in this solution, but if you want to replace the alcohol with fresh clear alcohol you absolutely can. It may take a few alcohol changes before the leeching completely stops and your alcohol remains clear.
If your specimen floats when you first add it to the alcohol there is likely an air bubble trapped in it. Try submerging the specimen and gently squeezing it or turning it to release any air bubbles.
If your specimen (commonly fetuses) begins to “leak” a whitish yellow substance from parts of its body, do not panic. This is another sign of excess leeching and is most commonly seen at the injection sites. Simply rinsing the specimen off with water and replacing the alcohol should fix this issue, though it may take a few alcohol changes before it completely stops.
What Do I Do Now?
Sit back and enjoy your new wet specimen knowing it’ll last generations if cared for properly!
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