Studies on Vitamin G(B2) and Its Relation to Canine Black Tongue

Hepatic Dysfunction in Dogs Fed Diets Causative of Black Tongue

“…The recent studies of Street (12) indicate that black tongue may be caused by feeding synthetic diets lacking the heat-stable vitamin B complex other than flavin. Furthermore Koehn and Elvehjem (13) have shown that black tongue is not prevented or cured by supplementing the Goldberger diet with flavin (B~), but that cure is effected by a substance in the B~ complex which is not adsorbed by Fuller's earth or by alcohol and ether. They consider it similar to, if not identical with, the antidermatitis factor for the chick (filtrate factor).…”

Growth Factors For Bacteria

“…Alcohol-ether precipitation. This procedure, as used for liver extract, has been described by Koehn and Elvehjem (1936 volume of concentrated potato extract was treated with 5 volumes of ethyl alcohol, then 6 volumes of ethyl ether were added with constant stirring. The precipitate was removed by centrifuging, washed with alcohol-ether, and dissolved in distilled water.…”

“…Treatment with Neuberg's reagent. Crude potato extract was made alkaline with sodium carbonate and precipitated with mercuric acetate as described by Neuberg and Kerb (1912). The mercury was removed from filtrate and precipitate with hydrogen sulfide, and the excess hydrogen sulfide was removed by boiling.…”

“…Since the pioneer work of Wildiers (1901) with yeast, and of Bertrand (1904) with bacteria, a great many microorganisms have been reported to require for growth certain "stimulants" present in extracts of plant and animal tissue. An adequate review of the earlier literature on this subject is given by Peskett (1933), while most of the later literature has been reviewed by Sayhun and collaborators (1936).…”

Experiments with pigs on a pellagra-producing diet

“…The filtrate from liver extract, after treatment with fuller's earth, has been found curative of canine black tongue [Koehn & Elvehjem, 1936] and also of human pellagra [Fouts et al 1936]. Sebrell, Onstott & Hunt [1937] also cured black tongue with material prepared by a similar method from rice bran by Lepkovsky and Jukes.…”