Rice as it comes from the thresher {" paddy " rice) is enclosed in a hull which must be removed by grinding the rice between atones, or, as in Burmah, in a larger mortar. The grain produced by this operation is brownish in color and consists of two parte, the endosperm and the embryo or germ. The whole is surrounded by an outer layer, the pericarp or " silver-skin," next to that is a layer rich in protein, known as the aleurone layer, and within this lie the starch grains.. In a little pocket formed by the aleurone layer at the end and to one side is the embryo. In order to remove the brown coat and thus meet the demand for a whiter rice grain millers have had recourse to more or less elaborate machines in which the grain passes through leather rollers which rub off the outer layer, the embryo becoming separated from the endosperm at the same time and being discarded with the polishings.

a. "Paddy" Rice.

b. "Brown Rice" from which the Hulls have been.

Fig. 8. c."Polished Rice".

Polished rice has the advantage that it keeps better than unpolished rice, which is likely to be infested with weevils and other insects.62

The change in the chemical composition of the rice due to the polishing process is shown in the following table:63

Starch Grains -Aleuront Layer -Pericarp -Embryo.

Fig. 9. - Rice Grain.

366, 1913; Z. f. phyaiol. Chem. 93, 13, 1914; Naturwise. 3, 131, 1914; Die Vita-mine, Weisbaden, 1914; Funk and Macallum, J. Biol. Chem. 33, 413, 1915; lb., 27, 1, 1916; Funk, Lyle, and HcCaakey, J. Biol. Chem. 37, 173, 1916; Funk, Bioch. Bull. 4, 304, 1915; 5, 1, 1916; Funk and Dubln, Sci. 52, 448, 1920.

62 See Ottow, " Testing, Storage, and Preparation of Unpolished Bice," Natuur. Tyjds. Ned. Indie, 74, 143, 1915.

63 U. S. Dept. Agriculture, Bureau Chem. Bull. 46.

Protein, fat, and mineral matter are all reduced by this process, and in addition the vitamin B which is present in the germ and in the pericarp and aleurone layer of all cereals64 is entirely removed. According to Funk it is the loss of this factor which leaves polished rice so unsuited to form the chief part of the diet.64a.

Vedder 65 suggests the existence of two vitamins, deficiency of one resulting in dry beriberi, and deficiency of the other causing wet beriberi. He bases this hypothesis on the fact that while the administration of unhydrolysed extract of rice polishing to cases of wet beriberi results in the prompt relief of the symptoms, in cases of dry beriberi administration of this extract is followed by little or no improvement in the paralytic symptoms. The administration of Funk's base66 to cases of dry beriberi produces an immediate improvement in these cases as well as in polyneuritis gallinarum, from which Vedder concludes that dry beriberi is caused by the deficiency of this substance in the diet, and that dry beriberi of man and polyneuritis gallinarum are essentially the same disease. Since wet beriberi, on the other hand, was cured by the extract represented by the filtrate from the phosphotungstic precipitate which does not contain Funk's base, Vedder concludes that wet beriberi is caused by deficiency of a different substance in the diet and that dry beriberi and wet beriberi are different diseases, deficiency of a separate vitamin being responsible for each.

McCollum and Davis67 made a complete study of the nutritive deficiencies of polished rice and found that it must be supplemented with additional protein, mineral salts, and both vitamins A and B in order to secure normal development. Experiments with other foodstuffs have shown that deficiency in any one of these factors is sufficient to limit growth, but only in the absence of B are polyneuritic symptoms seen. A supply of this factor, either from rice polishings, wheat embryo, yeast, or some other source, brings about rapid recovery from the disease and provides protection against its onset or recurrence.

64 See p. 78.

64a Sawamnra (Japanese Patent 98,720, July 6, 1020) found the embryo of rioe to afford the following analytical results: water 5.73, crude protein 2430, crude fat 20.12, lecithin 0.93, sugars 10.79, starch 1430, crude fiber 0.77, and ash 13.47 per cent. It contained a large quantity of vitamin. By treating with 02 per cent caustic soda solution the protein and fat, etc., in the embryo go into the solution; while, using 0.1 per cent hydrochloric acid, calcium phosphate, vitamin, etc., are obtained in the solution. The two solutions are mixed together and a small quantity of lime water is added. The precipitate thus obtained is collected, washed with water and dried. It contains a large quantity of vitamin and water 4.87, crude protein 41.55, crude fat containing lecithin 4650, and ash 336 per cent, P205 1.10 per cent and CaO 1.00 per cent.

65Vedder, "Beriberi," N. Y. 1013; Proc. 2nd Pan Am. Sci. Cong. Sect. 8, Pt. 2, p. 26; Vedder and Clark, Phil. J. Sci. 7,1012; Vedder and Williams, 76, 8B, 175, 1013.

66 See p. 121.

67 McCoUum and Davis, J. Biol. Ghem. 33, 181, 1915.

In the milling of wheat the bran and embryo of the wheat grain are removed as are those of the rice, although the process is different. The finer and whiter the grade of flour the more completely have the vitamin-bearing parts of the grain been removed. Where bread made from such flour forms a comparatively small part of a generous mixed diet this deficiency is unimportant, but where the bread forms the greater part of the diet, as was true of the cases in Labrador and Newfoundland reported by Little (1. c.) serious results may ensue.

The work of Punk and others on the isolation of the antineuritic substance from rice polishingB and other sources has been referred to elsewhere.68 While of great interest from the purely scientific point of view these contributions are much less important practically than the determination of the distribution of this substance in the natural foodstuffs.69 Since it is found in abundance in the cheapest foods, cereals and legumes, provided only that these have not been robbed of their store by the misguided efforts of civilized man to "improve " them, there is no reason why even the poorest races of mankind should continue to suffer from the ravages of beriberi. Repeatedly change of diet has been shown to result in the eradication of the disease from a community.70

68 See p. 121 and ff.

69 See pp. 66-88.

70 Van Leent, Arch, de Med. Nav. 1867, Oct. p. 241. Communication but le Beriberi, Cong. Internat. d. Sc. Med. Amst. 1880, vi, 170. etc.; Vorderman, Ondersoek naar het verband tusschen den aard der rystvoeding in de gevan-genissen of Java en Madoera en het voorkomen van beriberi onder de geinter-needen. Batavia, 1897; Takaki, Three Lectures on the Preservation of Health Amongst the Personnel of the Japanese Navy and Army. Lancet, 1906, 1, 1369, 1451, 1520, etc.; Fletcher, Journ. Trop. Med. and Hyg. 1909, zii. Lancet, 1907, i, 1776, etc.; Highet, Philippine Journ. Science 1910, v. 73; Weiser. Philippine Jour. Science 1911, vi, 1237. Also Jorn. Am. Med. Ass. 1911, LVI, 1238; These, Ann. d'Hygiene de Med. Col. 1910, xiii, 16; Chamberlain, Philippine Journ. Science, 1911, vi, 133; Veddcr, Beriberi, William Wood and Co., New York, 1913.