THE ETIOLOGY OF BERIBERI. 



57 



effects, and that its occurrence should be held as important confirmatory 

 testimony of the connection between white rice and beriberi. It is de- 

 sirable, however, to emphasize the point that the acceptance or nonac- 

 ceptance of this opinion is immaterial to the argument; for this purpose 

 the occurrence of the disease is employed only as a reaction. 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. 



The commercial varieties of white rice are numerous, but in this coun- 

 try, apart from the grading as to quality, two are in common use and 

 are known, respectively, as Siam and Eangoon. 



From epidemiological considerations and from experimental evidence 

 it appears that Siam rice is considerably more potent in its beriberi- 

 producing powers than Eangoon rice. 



The proteins, fats, carbohydrates, and ash were determined for the 

 different varieties of rice which had been employed in the experiments, 

 with the following percentage results calculated on dried material. 





Proteins. 



Fats. 



Carbohy- 

 drates. 



Ash. 





9.07 

 8.44 

 9.48 



0.17 

 0.81 

 0.51 



90.11 

 89.90 

 89.12 



0.65 

 0.85 

 0.89 



White rice (Rangoon) 





A comparison of these results shows that the only marked difference 

 among the rices was in respect to fat, which was most abundant in the 

 variety known as Eangoon, less abundant in parboiled rice, and still 

 less abundant in Siam rice. These observations, taken in conjunction 

 with the experimental results in fowls, excluded the possibility of an 

 explanation of the origin of beriberi on the ground of a deficiency in 

 fat. It will be noted that these analyses did not include an estimation 

 of the relative proportions of the inorganic salts composing the ash, nor 

 did they take account of the manner of combination, organic or inorganic, 

 in which these substances originally existed in the rice grain. 



By a method devised in this laboratory, sections of the various rice 

 grains were obtained of sufficient thinness to permit the examination in 

 detail of their histologic characters. By suitable staining methods it 

 was shown that in parboiled rice (Plate III, fig. 7) remnants of the 

 pericarp remained attached to the rice grain, whereas in Siam rice (Plate 

 III, fig. 8) the pericarp and the layers subjacent to it (subpericarpal 

 layers) had been polished away. It would appear that parboiling renders 

 the grain tough and nonfriable, in consequence the subpericarpal layers 

 can not be removed so readily as in the untreated grain. It was further 

 demonstrated that the layers so retained in parboiled rice contained the 



