Re: Bichromate Sausages
P.S. The effect of misconceptions being accepted as fact can range
from simply annoying or frustrating, in that they get in the way of
our attaining a correct understanding of the process, to
embarrassing, ( as in the assertion attributed to Horwitz, which
makes him look like he doesn't understand chemistry) to dangerous (as
in the misconception about the sausages, which was used repeatedly
here in support of the idea that it's perfectly harmless to eat
dichromates).
kt
On Jan 9, 2007, at 10:11 AM, Katharine Thayer wrote:
Yes, that's the original citation from which the mistaken idea of
dichromates used as preservatives in sausage, arose, as I related
in the account that I linked earlier.
It always seems to work like this: someone remembers something
someone said or cited but doesn't remember the original assertion
or citation quite right, and then the misconception gets repeated
and repeated until it becomes the "fact." That's why it's so
important not to rely on secondary sources.
kt
On Jan 9, 2007, at 9:48 AM, Liam Lawless wrote:
Just for fun, here's the passage referred to, from Vogel's 'The
Chemistry of
Light and Photography in their Application to Art, Science, and
Industry'
(mine is 6th, ed., 1892):
Section XII. - THE CHEMICAL ACTION OF LIGHT, AND THE PEA-SAUSAGE.*
In the campaign of 1870, the well-known pea-sausage was one of the
most
important articles of food for the army, and was prepared daily by
thousands. The fabrication of the interior portion caused little
difficulty, but the obtaining so many skins created much
difficulty. As the
supply fell short, a substitute was sought in vegetable
parchment. This
paper, which is produced by dipping blotting-paper in sulphuric
acid for
about a second, then washing and drying, is distinguished by its
skin-like
properties of resistance. It is impenetrable to water, and
difficult to
tear. It is therefore used for the production of bank-notes. It was
attempted to make sausage skins of this paper, by doubling a skin
cylindrically and pasting it together. No glue or gum can however
resist
the effect of the boiling water in which the sausage has to be
cooked, and
so the artificial sausage skin fell asunder. Dr. Jacobson solved the
problem by producing an adhesive substance, with the help of the
chemical
action of light, which could resist boiling water. He mixed the glue
intended for the sausage skin with bichromate of potash, and
exposed the
glued parts to the light. This made the glue insoluble, and now the
artificial skin endured boiling water thoroughly well. The number of
sausage skins prepared in this way, by the chemical action of light,
amounted to many hundred thousands.
* Erbswurst.
Liam
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