The preparation described by Suzuki, Shima-mura and Odake, and called by them oryzanin was certainly not a distinct compound, but a relatively complex mixture of substances extracted from rice polishings (2).

Edie, Evans, Moore, Simpson and Webster (3) obtained an active fraction from yeast, which they regarded as belonging to the pyrimidin group. This preparation they termed torulin.

Williams and Seidell (4) prepared a sample of adenin from yeast, and found that it had curative properties for polyneuritis in pigeons, but these were lost on keeping. They attributed the change in the physiological effect of the adenin relative to its anti-neuritic properties to molecular arrangement. The loss of anti-neuritic power they attributed to the gradual passing over of an unstable compound into a stable form. Voegtlin and White (5) and Harden and Zilva (6) have been unable to confirm these observations.

Abderhalden and Schaumann (7) have published a paper in which they describe attempts to isolate the anti-neuritic substance from yeast. They introduced two new terms (eutonin and nutramin), but otherwise made no advance toward the solution of the problem of isolating the anti-neuritic complex.

Hofmeister (8) reported that he had isolated a substance which he identified as a pyrimidin, and which possessed anti-neuritic properties.

Funk and others isolated nicotinic acid from rice polishings. The idea has been expressed that this or some unstable modification thereof, is the anti-neuritic substance. Extracts of rice polishings prepared according to the usual procedure for securing the "vitamin fraction," have been observed to develop a pyridin-like odor. Furthermore, Drummond and Funk (9) noted that preparations which were capable of curing pigeons of polyneuritis always gave the characteristic blue color with the Folin-Macallum phenol reagent, indicating the presence of a substance or substances containing hydroxyl groups (10).