The Differential Extraction from Dried Brewers’ Yeast of the Antineuritic (vita-

Since the demonstration of the dual nature of vitamin B in 1926 (1, 2) which has been amply confirmed in recent years (35), there has been no satisfactory method for the separation of the heat-labile antineuritic (vitamin B,) from the more heat-stable growth-promoting (vitamin B,) component of the vitamin B complex. There are numerous experiments recorded in the lit,erature indicating that at least partial separation of the two vitamins might be effected either by differential solubility in certain solvents or by differential adsorbability on certain adsorbents. Actual attempts in this direction made upon material rich in the two vitamins, such as yeast, have not met with much success (6-11). It appears from the foregoing that for practical purposes the only reliable source of vitamin B,, nearly if not completely free from vitamin B,, is still an autoclaved yeast or yeast extract, as first suggested in 1926 (1). To get further information on the relation of vitamins B, and B, in the nutrition of the white rat and their role in the production of experimental polyneuritis in this animal, it appeared desirable to attempt to obtain a vitamin B, fraction by removing intact the vitamin B, component from material containing the complex rather than destroying it by heat as is done in the autoclaving process. The advantages of such a procedure are too obvious for discussion. The present work deals