Our knowledge of the antineuritic properties of foods has been obtained through the study of beriberi in man or of experimental beriberi in fowls or pigeons. While the symptoms of beriberi are variable the disease is chiefly characterized by degeneration of the nerves beginning with those of the extremities ("polyneuritis," "multiple peripheral neuritis").

For a long time beriberi was very common in the Orient (Malay States, Siam, parts of Japan and the Philippines) and in recent years beriberi has also been found in Newfoundland and Labrador. Cases are also occasionally reported from the southern and western parts of the United States.

Takaki, while Inspector General in the Japanese Navy, was much disturbed at the large proportion of men who suffered from beriberi, and in 1880 began a systematic investigation which indicated that the frequency of the disease was more closely connected with the nature of the food than with any other probable factor since climate was found to be without influence and the sanitary conditions on the Japanese ships were as good as those in the European navies which were not troubled with the disease.

A Japanese naval vessel with 276 men on a 9 months' cruise from Japan to New Zealand, Valparaiso, and Honolulu had 169 cases with 25 deaths. Another vessel with a similar crew was sent by Takaki over the same route with a ration in which the rice was decreased, the barley increased, and vegetables, meat, and condensed milk added. In this case only 14 men had beriberi and each of these had failed to eat his full allowance of the new foods. As the result of this experiment Takaki secured the adoption of his new ration for the entire Japanese navy with the result that the number of cases of beriberi soon became practically negligible.

Takaki attributed this to the fact that the new diet was richer in protein, having a ratio of 1 part nitrogen to 16 parts carbon, whereas the old ration had only 1 part nitrogen to 28 parts carbon. The great reduction in beriberi was undoubtedly due to the change of diet, but not primarily to the increased protein intake. Apparently because the explanation available at the time was not sufficiently convincing, Takaki's great achievement was not fully appreciated, and medical opinion continued for several years to regard beriberi as possibly an infectious disease. But no success attended the attempts to check the disease by sanitation, while indications that the cause might be nutritional continued to be found.

In 1907 Braddon published in his book, "The Cause and Prevention of Beriberi," a large amount of evidence connecting the disease with the eating of polished rice.

At about the same time Fletcher, by experimenting with the diet in a lunatic asylum, showed that when 28 oz. of rice was fed daily with only small amounts of other food, the use of polished or unpolished rice was alone sufficient to determine the occurrence or non-occurrence of beriberi.

During 1907-1908 Fraser and Stanton took 300 laborers from Java into new and sanitary quarters in a virgin jungle and demonstrated in striking fashion that with rice as the main part of the diet, beriberi followed the use of polished but not of unpolished rice. Many other observations to the same effect were also published at about this time.

In 1909, convinced that beriberi was related to diet, the U. S. Army Medical Commission in the Philippines initiated changes in the rations of the "Philippine Scouts" and in 1911 Chamberlain was able to announce the eradication of the disease'from these troops by the substitution of unpolished rice (and a small quantity of beans) for the polished rice previously used. Until the year 1910, the number of hospital cases of beriberi ranged from 115 to 618 (the force numbering about 5000 men). During 1910 changes in the dietary were begun and that year the cases dropped to 50. In 1911 there were 3; in 1912, 2; in 1913, none; in 1914 up to June 30 (date of latest available report) there was 1.

In 1908-1909, when beriberi was at its worst among the Scouts, the diet consisted essentially of 12 oz. of beef, 8 oz. of white flour, 8 oz. of potatoes, and 20 oz. of rice (ordinarily polished). The change in the ration, as finally decided upon after some months of experimentation, consisted in giving, in place of the 20 oz. of polished rice, 16 oz. of unpolished rice and 1.6 oz. of dried beans. Experiments, made largely upon fowls as explained below, have shown that while meat has some effect in preventing beriberi, an equal weight of beans, peas, or peanuts is much more efficacious.

A further improvement could have been made by substituting some whole grain product for the white flour since it is now known that a diet consisting too largely of white flour or bread may in itself be a cause of beriberi; * but this appeared unnecessary inasmuch as the changes already noted sufficed to eradicate the disease.

Chamberlain states, in fact, that the disease had disappeared as the result of adding the beans to the ration, before the substitution of unpolished for polished rice had been completed. He believes "that the consumption of beans to the daily amount of 1.6 ounces would, unaided, have prevented a recurrence of beriberi, but it would obviously be difficult to make sure that all the men ate their share of this article over long periods, and it is therefore much safer that the largest component of the diet, the rice, should be of the unpolished variety and by itself sufficient to prevent neuritis."

Several other investigations gave similar results. These repeated demonstrations of a close connection between a diet consisting too largely of polished rice and the occurrence of beriberi naturally gave a great impetus to experiments de-signed to find what constituents of the rice are directly concerned in the disease.