What also might need to be considered is how long the bones are soaked in
the vinegar/acetic acid solution. In my own experience, when soaking bones
to remove quite heavy calcium carbonate, I've only submerged bones for
approximately 45 minutes at a time (followed by 2 x 1 hour water soaks to
remove any lingering acid). Any longer than this, and there was a real
concern that the bone surface would become too friable for taphonomic
analysis.
Roughly along the same lines as Richard, I would imagine that fresh bone
could withstand a much longer soaking period, with the collagen preventing
surface exfoliation, allowing it to become malleable. Although, as Sheila
has mentioned, this may work very well for something as relatively thin as a
rib bone (even though pig ribs are quite dense, comparatively speaking), I
have no idea how long you would have to soak a long bone shaft in order to
'roll' it the way it appears to have been done in the photo.
I imagine there will be a great many of us making visits to the butchers and
collecting the household vinegar supplies to give this a try.
Emma Humphrey, PhD.
Department of Anthropology
University of Toronto
-----Original Message-----
From: Analysis of animal remains from archaeological sites
[mailto:[log in to unmask]] On Behalf Of Richard Wright
Sent: June-04-12 6:46 PM
To: [log in to unmask]
Subject: Re: [ZOOARCH] help with modified bone
I have to yield on the question of vinegar, because an experiment is worth a
thousand words of theory.
So there must be a difference in the response of green and decollagenized
bone, when it comes to reaction with vinegar.
It is possible also, I suppose, that juvenile bone, compared with adult
bone, has a higher proportion of calcium carbonate than calcium apatite.
I'm off to get myself some pork spare ribs and a bottle of vinegar
Richard Wright
On 5/06/2012 08:55, S Hamilton-Dyer wrote:
> Well.... that may be true but I have 'dissolved' sheep and pig ribs in
> vinegar or lemon juice in order to tie them in a knot - to demonstrate
> that bone has several constituents, you can also do this to eggs to
> get the 'ship in a bottle' effect. The bone or egg goes soft and
> rubbery but hardens again when dried out.
> Although I have just come back from seeing Hawkwind (in fine form!), I
> am not imagining this trick, I was shown it many decades ago.
> Sheila
>
> SH-D ArchaeoZoology
> http://www.shd-archzoo.co.uk
>
>
> On 04/06/2012 21:59, Richard Wright wrote:
>> Lucretia
>>
>> The acetic acid in vinegar would not produce the desired result.
>>
>> In fact acetic acid has for long been used to extract bones from a
>> matrix of calcium carbonate, because it does not dissolve the major
>> mineral component of bone - calcium phosphate.
>>
>> http://onlinelibrary.wiley.com/doi/10.1111/j.2151-6952.1959.tb00514.x
>> /abstract
>>
>>
>> It would have to be a mineral acid - and the acid that would dissolve
>> the mineral component but leave the collagen intact is nitric acid.
>>
>> Richard
>>
>>
>>
>> On 4/06/2012 23:39, Lucretia S. Kelly, Ph.D. wrote:
>>> Richard and other Zooarchs,
>>> Unfortunately I didn't get many responses other than the
>>> modified bone is weird.
>>> [http://zooarchaeology.ning.com/photo/photo/listForContributor?scree
>>> nName=36a31yu12ezfl]
>>>
>>> The one scenario that makes some sense to me is that the bone was
>>> soaked in vinegar or a vinegar solution that rendered it pliable
>>> enough to be rolled or folded. I have heard that this can be done
>>> with chicken bones, but have no knowledge of it with thicker mammal
>>> bones. It appears the occupants of the site were pickling pigs feet
>>> so they many have been familiar with how brining affects bones and
>>> this may be a by-product of that process. I received no thoughts on
>>> for what purpose the bone may have been used. I think I see some
>>> experimentation in my future to see if this can be accomplished with
>>> vinegar and, if so, how long it would take for the bone to become
pliable.
>>> I am open to other possibilities.
>>> Lucretia
>>>
>>> Lucretia S. Kelly, Ph.D.
>>> Research Associate
>>> Dept. of Anthropology
>>> Washington University-St. Louis
>>> [log in to unmask]
>>> cell phone: 618-550-9312
>>> home phone: 618-281-5369
>>>
>>>> Lucretia
>>>>
>>>> I find the specimen remarkable, having never seen anything like it.
>>>>
>>>> Thinking aloud, one can assume the distorting effect could only be
>>>> achieved in a bone that had a high collagen to mineral ratio.
>>>>
>>>> If that assumption is correct, then two explanations can be
>>>> considered.
>>>>
>>>> 1. The bone is from a fetus or neonate, where mineralization of the
>>>> bone is low. Perhaps cooking distorted the bone, but then one would
>>>> have to ask why such cases are not more common.
>>>>
>>>> 2. A more mature bone was partially demineralized with dilute
>>>> nitric acid. If totally demineralized then it would have perished
>>>> in the ground.
>>>>
>>>> It would be good if you ultimately gave us a summary of suggestions
>>>> that come to you off list.
>>>>
>>>> Richard Wright
>>>>
>>>> On 2/06/2012 03:21, Lucretia S. Kelly, Ph.D. wrote:
>>>>> Dear ZOOARCH members,
>>>>>
>>>>> I have a type of modified bone from an historic site (mid 1800s)
>>>>> in Southern Illinois, USA that I have never seen before and wonder
>>>>> if anyone has seen something like this. It is a mammal bone
>>>>> (possible pig since the site has many pig bones) that has been cut
>>>>> lengthwise and on the ends, then rolled or folded over on itself.
>>>>> I would like to know how this could be accomplished and what type
>>>>> of artifact this may have been. I have uploaded pictures to
>>>>> ZooBook:
>>>>>
>>>>>
http://zooarchaeology.ning.com/photo/photo/listForContributor?screenName=36a
31yu12ezfl.
>>>>> Thanks much.
>>>>>
>>>>>
>>>>> Lucretia S. Kelly, Ph.D.
>>>>> Research Associate
>>>>> Dept. of Anthropology
>>>>> Washington University-St. Louis
>>>>> [log in to unmask]
>>>>> cell phone: 618-550-9312
>>>>> home phone: 618-281-5369
>>>>>
>>
>
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