Friday, August 2, 2013

Old scorpions, new tricks

    One of our efforts here at the museum is to take better care of our old material and specimens since it is our job to protect them for future generations. One way of preserving biological materials for several years (many or, in our case, decades) is to store them in alcohol. Back in the day, before there was pure distilled alcohol, specimens would be stored in "spirits" (a.k.a. moonshine, vodka, rum, etc.) because that was the highest grade they could get. Early scientists found that the high alcohol content helped prevent bacterial and fungal growth, thereby slowing decay. Now most specimens are stored in either lab-grade mixtures of ethanol (which is the alcohol found in beer/wine) or isopropyl (rubbing alcohol...mostly just fish now). In our collection of Recent Invertebrates, its 75% ethanol to 25% water. This keeps our specimens in relatively good shape but doesn't completely dry them out (most organisms are a large part water, and by osmosis when you put them in high alcohol content, the water goes out of them into the solution, drying them out). Here is a link of a nice exhibition featuring over a million specimens preserved in alcohol in Berlin, Germany, for an example of a large collection in alcohol.
Scorpions from the 1930s on the right being rehoused in new alcohol on the left.
    Water with osmosis is not the only thing that unfortunately leeches out of the specimens over time with alcohol. Many specimens loose their color, and alcohol soluble chemicals come out. That is why the jar on the right in the picture above is reddish/orange. The fats and other chemicals from the scorpion specimens and the wooden corks used to close the containers leached into the alcohol. And, that is at least 80 years of buildup, since some of the scorpions in that jar were collected in 1931! With the alcohol that color and the corks almost completely dissolved, we decided to give the scorpions a face-lift and replace the nasty alcohol with new, fresh alcohol so we could see the specimens and new cotton stoppers that could easily be removed to look at the specimens or change them out. Now we just have to catalog them, and the scorpions are ready to go for a researcher to study them!
      I hope everyone has a good weekend, and we'll update you more on the collection next week!