Riboflavine 187
brings almost immediate improvement. It has also been sug-
gested that lack of it may predispose to chilblains. The skin-
protector for chicks has turned out to be pantothenic acid
and is probably universally needed by all living organisms.
Various other factors supposed to be necessary for normal
growth in birds or rats, or to prevent anemia, cataracts, giz-
zard lesions, failure of lactation, and even gray hair, have
been described, but the distinctness of many of these is doubt-
ful, and evidence of their need by human beings has yet to be
obtained. For the present, at least, we need not concern our-
selves about them as necessary parts of our daily diet.
RIBOFLAVINE
As noted above, when the principal growth-promoting
member of the vitamin G family was finally unmasked, it
proved to be a yellow dye of the flavine group which had
long been known as a component of milk, egg white, meat,
and many plant substances. Various names had been given
to it according to its source, e.g., lactoflavine, ovoflavine,
etc., but since these are apparently all alike, the name ribo-
flavine, which has only chemical significance, has been ap-
proved for it. It is not easily destroyed either by heat or
alkali. It forms combinations with phosphoric acid and
proteins, and in the combined form acts as an enzyme which
has an important function in the body in connection with
oxidations. An interesting interrelation of vitamins appears
from the fact that this “yellow enzyme” requires the as-
sistance of a compound in which nicotinic acid, another of
the vitamin B family, is an ingredient.
Young rats are unable to grow if deprived of riboflavine,
and older animals rapidly lose weight and become un-
healthy. Recently the failure of bone marrow cells to form