[Nhcoll-l] Speculation on color retention and color loss in preserved herps?

[Cassidy, Kelly Michela]

Curious about herp preservation techniques that affect color retention and loss.

We have a garter snake that was once used as a display and/or teaching specimens. It was in a straight glass tube, sealed at the ends with a black tarry substance. About 10 or 15 years ago, I removed the snake from its glass tube because the fluid and glass had become too discolored for it to be a suitable display specimen.  I rinsed it and transferred it to a jar in 70% ethanol, but I am not sure what the fluid in the original tube was. The snake was collected in 1938. For a specimen approaching 90 years old, its color pattern was unusually sharp, but it is also much more flaccid than a typical snake fixed in formalin and preserved in ethanol. (Picture attached.) Any idea what fixative or storage chemicals might have caused better color retention but might have been less good at preservation, leading to more flaccidness?


On the other end of spectrum, we have a number of specimens, most from the mid-20th century (1950s to 1970s) that are now almost entirely bleached of color. These nearly white specimens came to Conner Museum as part of an "orphaned" collection (from Walla Walla College). Not all of the specimens from Walla Walla are bleached out. I am guessing there was a period when their fixative or storage solution contained or lacked something that caused unusual bleaching. We have no records from the collection about fixative or storage methods. What is the most likely cause of such extreme bleaching? Lack of buffering or chemicals used for buffering?  Storage in denatured ethanol?


Dr. Kelly M. Cassidy, Curator, Conner Museum
School of Biological Sciences
Box 644236
Washington State University
Pullman, WA 99164-4236
509-335-3515

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