IV
THE OFFSPRING OF THE “B” FAMILY—RIBO-
FLAVINE, NICOTINIC ACID, ETC.
OON after the wonderful effect of extracts of rice pol-
ishings on polyneuritis in pigeons and beri-beri in man
was discovered, it was found that a water-soluble substance
present in milk, yeast, and other foods was essential for
growth in rats. At that time this was believed to be identical
with the substance which would cure beri-beri. Rats de-
prived of foods containing it would in a few weeks lose
weight, become weak and anemic, and die. One grain of
compressed yeast would produce signs of returning health
in a few hours, and there would be an immediate resumption
of growth.
Experiments beginning about 1919 indicated that the
substance which protected pigeons from polyneuritis and
man from beri-beri was not identical with the substance that
made it possible for rats to grow. Yeast could be heated to
a point where its nerve-protecting powers were destroyed,
and still be capable of promoting growth. Moreover, some
substances, such as rice polishings and wheat germ, were
found to be much more potent in protecting nerves than in
promoting growth, whereas the opposite was true of such
things as lean meat, egg white, and milk. The upshot of it
was that after about seven years of argument and experi-
ment the growth-promoting substance was recognized as
a separate and distinct vitamin, and was christened B2 in
Europe and G in America, while the nerve-protecting sub-
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