[NHCOLL-L:2890] Switching preservatives

[Darrel Snyder]

It is common practice to fix biological specimens in formalin (usually 
5-10%) and later transfer them to 70% ethanol for long term storage and 
use.  But with small soft-bodied organisms such as fish larvae, alcohol 
preservation results in considerable dehydration and shrinkage (effects 
reduced by runnin g specimens through a stepped series of ethanol 
concentrations), as well as making tissue more opaque than if the specimens 
had been kept in formalin.

I was recently asked whether specimens could be effectively reconstituted 
from 70% ethanol back to a 5% formalin solution and if so, what effect such 
might have on the specimens both short-term and long-term.  I had to say I 
didn't know and was not aware of any literature on the matter.  Does anyone 
on the list have any experience with converting fish (or any organism) from 
alcohol back to formalin or know of any published references on such?

Darrel Snyder
Larval Fish laboratory
Colorado State University