This simple molecule (D-tartrate, C4O6H3-) played a crucial role
in the
history of science.
Think of crystals in a wine bottle
(Weinsäure), stereochemistry,
Louis
Pasteur, chirality.
Remember how Louis Pasteur meticulously separated tiny crystals of two
mirror-image forms of tartaric acid
in 1847, showing how the two substances were chemically identical, but,
amazingly, caused polarized
light to be rotated in opposite
directions?
He arbitrarily assigned the two piles of crystals as left (L) and right
(D), setting the cornerstone for chemistry and biology, medicine,
pharmacology...
How do we know which is which?
In 1951 JM
Bijvoet published the definitive experiment that proved that
Pasteur had correctly chosen the 'D' form to correspond to the D/L
assignnmet rules given by Emil Fischer
from his study of sugars. From these studies, Fischer concluded that
molecules must fit like a "lock
and key", using a metaphor from the mechanical age (Pharma.
Acta Helv., 69:177-183).
Other images of sculptures will be added.
I wish to thank Prof. Pedro Alzari,
director of the crystallographic labortory at the Institut Pasteur, Paris,
France.
Pasteur's home, laboratory, and crypt constitute a remarkable museum
for the history of science and his amazing scientific contributions
(rabies vaccine, pasteurization, debunking vitalism, etc.)
A very readable account of Pasteur's research can be found is a small
pocket book by Isaac Asimov, "The Left Hand of the Electron"
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