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 Storing flies in alcohol
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| cosmln |
Posted on 31-07-2008 08:15
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 Member Location: Posts: 956 Joined: 18.03.07 |
just a question. right now i use alcohol (ethanol) of 87 grades. this mean is of 87%? i have forget all chemistry i have learned  thanks in advance, cosmln |
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| Tony T |
Posted on 31-07-2008 13:52
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 Member Location: Posts: 661 Joined: 08.02.07 |
jorgemotalmeida wrote: Ralph Sipple wrote: Hi together, sorry for necroing this thread. jorgemotalmeida wrote: ..."NEVER use formaldehyde because it alters the structures of the specimens"... Regards Ralph Maybe in infinitesimal quantities it doesn't harm the specimens. But if you only use Formaldehyde it is sure that it will damage the structures of the specimens. "The Preservation of Natural History Specimens. I. Invertebrates. R. Wagstaff and J. H. Fidler. 1961." I have found this to be a most authoratative text. pp. 171-172: "Formalin - this is the most useful preservative. It is slightly acid and may damage specimens containing calcareous matter. it may be neutralized by being shaken with powdered chalk (5 gm/litre) and then filtered. Borax may also be used for the same purpose. If formalin is neutralized the colours of specimens are generally better preserved than when in alcohol. Use at 3-10% for storage. As a preservative formalin is to be recommended for the more delicate soft-bodied animals as if used in the correct proportions it does not cause shrinkage" I (TT) used to use formalin to 'fix' animal tissue prior to section cutting on a microtome. Tissue and cells were perfectly preserved; not sure what Jorge means by "it will damage the structures of the specimens" Edited by Tony T on 31-07-2008 13:55 |
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| jorgemotalmeida |
Posted on 31-07-2008 21:44
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 Member Location: Posts: 9295 Joined: 05.06.06 |
maybe, I must rewrite the sentence. I want to say: it can alter the shape of the specimen. Not necessarily damaging them. |
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| Adrian |
Posted on 01-12-2008 16:10
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Member Location: Posts: 69 Joined: 05.01.07 |
Interesting discussion:- lots of pro's & cons for wet and dry preservation. A couple of points /tips to consider with alcohol preservation 1. If you kill a fly in Gaults solution or a dilute aqueous salt solution (even urine works well if you are really stuck for supplies out in the wilds!), all everscible structures evert, abdomens become fully expanded and the legs adopt an outstretched position. Just wash out the salts with water or low strength alcohol and then store or dry as per normal. I find that if subsequently dried properly, the material is much better to work with than the shrivelled distorted and sometimes mouldy material that has been impaled on a pin in the field 2. Some flies have a high oil content and get greasy on storage with setae matting etc (e.g. therevids seem to be prone to this). When drying from alcohol, you have to transfer toan apolat solvent like ethyly acetate to dry them out. Such solvents also remove the offending oils and the dry specimen never gets greasy. On the down side, when the oils have been removed, a specimen will be less strogly bound to a pin soit is probably better to card mount stuff dried from alcohol. cheers Adrian |
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