The Physiological Rôle of Vitamin B: Part V. The Relation of Inanition to Vitamin B Deficiency in Pigeons.

PREFATORY NOTE. THROUGHOUT this paper vitamin B refers to the accessory food factors present in yeast. We have satisfied ourselves that pigeons fed on a synthetic diet of the type used throughout this work but supplemented with 4 % of yeast extract that has been heated with alkali for 4 hours to destroy the "antineuritic " factor behave exactly as do those which receive the unsupplemented ration. The presence of the treated yeast extract, providing amongst other substances the heat-stable factor [Hassan and Drummond, 1927], does not ameliorate the condition, or retard the decline or the onset of nervous symptoms, at any rate in the case of birds feeding voluntarily.