[NHCOLL-L:4915] Re: Isopropanol as a preservative

[Richard Rosenblatt]

I won't argue the point, but I know herps are placed directly into 
ethanol, as were fishes until the introduction of formalin in the 
early 20th century (?) Try that with isopropanol and you will soon 
have a pile of bones in the jar.


>Ethanol also lacks fixative properties!  It preserves mostly by dehydration.
>
>
>From: owner-nhcoll-l at lists.yale.edu 
>[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Richard 
>Rosenblatt
>Sent: Sunday, August 01, 2010 12:04 PM
>To: NHCOLL-L at lists.yale.edu
>Subject: [NHCOLL-L:4914] Re: Isopropanol as a preservative
>
>Malcolm: Unlike ethanol, isopropanol is not a fixative. The fishes 
>must have been fixed in formalin before being placed in iso.
>
>
>
>
>>The Arkansas State University Museum of Zoology has maintained 
>>fishes in isopropanol for decades.
>>
>>The hereptology specimens are kept in ethanol (after 24-48 hr 
>>fixing in formalin) for various reasons, but the fishes are housed 
>>in isopropanol
>>
>>and the preservation is pretty darn good.  I do not know if the 
>>fishes are formalin fixed first.
>>
>>
>>
>>Malcolm
>>
>>On Sat, Jul 31, 2010 at 5:12 PM, Richard Rosenblatt 
>><<mailto:rrosenblatt at ucsd.edu>rrosenblatt at ucsd.edu> wrote:
>>Amplifying HJ walkers brief comment, the Scripps Institution of 
>>Oceanography Marine Vertebrate Collection and  UCLA fish 
>>collections converted  to 50% Isopropanol in 1952. I came from UCLA 
>>and became curator in 1958 and continued the policy. The SIO 
>>collection now contains more than two million specimens, many of 
>>them delicate deep-sea fishes. We soon learned of the relative 
>>immiscibility of iso in water and the necessity to stir and bring 
>>preservative up to strength after washing out formalin. One 
>>advantage not often mentioned about iso is that when working with 
>>specimens it is not necessary to keep dipping them in water or 
>>spraying nearly as often as with alcohol specimens. When working 
>>with alcohol specimens you can see the scales curling and the 
>>fin-rays rapidly drying out under the microscope. I attribute this 
>>to the 50% water content as well as the lower vapor pressure of iso.
>>Without belaboring the point, or entering controversies over 
>>possible chemical reactions, I can say that we have maintained our 
>>collection for more than 50 years in 50% isopropanol  with 
>>excellent results.
>>
>>
>>
>>
>>--
>>Malcolm L. McCallum
>>Managing Editor,
>>Herpetological Conservation and Biology
>>
>>1880's: "There's lots of good fish in the sea"  W.S. Gilbert
>>1990's:  Many fish stocks depleted due to overfishing, habitat loss,
>>             and pollution.
>>2000:  Marine reserves, ecosystem restoration, and pollution reduction
>>           MAY help restore populations.
>>2022: Soylent Green is People!
>>
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