RICE DIET. . 179 



and the beriberi-preventing qualities of the parboiled or "cured" rice, but thought 

 the former carried a toxin generated in it after milling. 



Others, having in mind the evidence furnished by previous experiments and 

 epidemics, felt that a privation theory would best account for the occurrence 

 and distribution of beriberi, and experiments were conducted with prisoners, 

 laborers, etc., to prove or disprove the correctness of their deductions. 



It remained for Fraser and Stanton (6) in 1908-9 to prove beyond 

 all reasonable doubt, in a series of experiments on laborers in the Malay 

 Peninsula^ that beriberi conld absolutely be prevented by feeding "cured" 

 (parboiled) rice^ and that it would occur in the same places and under 

 the same conditions when the men were given polished rice. Since these 

 experiments it has been shown in many countries that the feeding of 

 undermilled rice (which had not been parboiled) has the same beriberi- 

 preventing influence as the use of the parboiled grain and that the bene- 

 ficial effects of cured rice are due to the adherent pericai'p and aleurone 

 layer and not directly to the process of "curing." 



As Fraser and Stanton so well put it, (7) "The fact that certain white rices 

 when forming the staple of a diet in man produce beriberi rests on quite other 

 testimony than that supplied by experiments on domestic fowls." As a result 

 of their exeriments on fowls they concluded (7) that while the etiologic connection 

 of polished rice and beriberi was proved by previous experiments on man, the 

 development of multiple neuritis in foM'ls when fed certain rices is an accurate in- 

 dicator of the beriberi-producing powers of those rices. 



Aron, (8) while not going so far, says, "These experiments give us a basis 

 of investigatio]! in order to ascertain the importance of the lack of certain food 

 constituents (such as phosphorus) in producing pathologic changes in the nerves 

 and other tissues." 



II. CHEMICAL COMPOSITION OF PHILIPPINE RICES. 



Besides these biologic tests, it is now thought by many (7), (8)^ (9) 

 that the phosphonis content is a good guide in the selection of a beriberi- 

 preventing rice, but, as yet, no absolute standard has been adopted 

 generally. 



The oflScials of the Health Department in Hongkong consider that a rice 

 will not cause beriberi if 0.4 per cent of phosphorus pentoxide is present. As 

 a result of analyses, conducted in the Chemical Laboratory of the Bureau of 

 Science in Manila, Aron considers that a rice is safe when it contains 0.45 per 

 cent of phosphorus pentoxide and unsafe if it contains less than 0.35 per cent. 

 An undermilled rice from Siam, called "Asylum No. IV," and which Dr. Highet 

 has found by practical experience to be capable of preventing beriberi, was sho-mi 

 at the Bureau of Science to contain 0.52 per cent of phosphorus pentoxide. 



Whether or not we consider lack of phosphorus to be the cause of 

 beriberi it seems quite generally to be accepted that the amount of phos- 

 phorus in a given sample of rice is a reliable index of the beriberi-pro- 

 ducing power of the grain when used as the principal article of the 

 diet. Samples of the rices used in the succeeding experiments and also 



