Vitamin Bi
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and pyruvic acid accumulates, especially in the brain. It is
doubtful whether carbohydrate metabolism can go forward
in any living cell without thiamin. The most prevalent be-
lief is that thiamin acts as an enzyme to bring about the
final oxidation. It certainly enables isolated brain cells to
do this. There is also some evidence that it enables the
body to build fat out of the pyruvic acid. Just how the
failure of the carbohydrate oxidation at the pyruvic acid
stage interferes with the nervous system is still to be solved,
but the speed of recovery when thiamin is injected under the
skull of pigeons sitting with the back of the head touching
the back, and turning cartwheels like a decapitated chicken,
is little short of magical.
As would be expected, the more calories the body uses
the more thiamin is required. This explains why the pro-
digious use of sweets by Americans, accompanied by exten-
sive use of white bread, but with insufficient vegetables and
whole grains, has plagued us with children who won’t eat,
and who become weak and sickly.
Only severe and continued lack of thiamin results in beri-
beri. The outstanding symptom of the disease is an exten-
sive degeneration of the nervous system. Both motor and
sensory nerves are affected, the former causing paralysis,
the latter numbness, itching or prickling sensations, and
painful sensitiveness to pressure. The nerve degenerations
usually begin in the feet and legs and travel up. In many
cases the skin and body cavities fill up with fluid, a condition
called dropsy. The lungs, and also the cavity surrounding
the heart, fill up with fluid, and the heart itself becomes en-
larged and dilated, and slowed in its beat; usually death is
caused by its sudden failure. Loss of appetite, constipation,
Ianguidness, breathlessness, muscular weakness and sensi-
tiveness, and loss of voice are other characteristic symptoms.