60 FRASER AND STANTON. 



methods precise differences between various rices. Such differences, if 

 they are to furnish an adequate explanation for the origin of beriberi, 

 must be in accordance with clinical observations and the experimental 

 results in fowls. 



In view of the important role played by phosphorus compounds in the 

 metabolism of nerve tissues, the amount of phosphorus in various kinds 

 of rice was determined as phosphorus pentoxide. The result of a large 

 series of observations showed that a reduction in the amount of phos- 

 phorus pentoxide obtained from rice was directly related to the probability 

 of the rice producing beriberi ; in other words, the higher the phosphorus 

 content of a rice the less was the liability of that rice to produce the 

 disease, and vice versa. 



Thus, a sample of parboiled rice which was fed to fowls over many weeks all 

 remaining healthy, was found to contain 0.469 per cent P 2 5 and a sample of white 

 rice which produced polyneuritis in fowls yielded 0.277 per cent P = 5 . The rice 

 polishings employed in experiment C yielded 4.2 per cent P 2 5 . 



From a series of observations it was determined that a fowl under 

 the conditions of our experiments, weighing from 1,200 to 1,400 grams, 

 required 60 grams of parboiled rice daily to maintain it in health and in 

 nutritive equilibrium. In experiment C it was determined experimen- 

 tally, the chemical analysis being then unknown, that when fed on white 

 rice a fowl of this weight required the addition of about 3.5 grams of 

 polishings to preserve it in nutritive equilibrium. Prom the data given 

 above it may readily be calculated what amount of polishings added to 

 white rice, is required to raise the phosphorus content of the white rice 

 diet to that of the parboiled rice. Thus 



Grams P.,0 5 . 

 60 grams of parboiled rice 0.3120 



60 grams of white rice 0.1662 



Difference 0.1458 



Polishings contain 4.2 per cent of phosphorus pentoxide. 



Calculated from the phosphorus content, therefore, 3.47 grams of polishings 

 added to the 60 grams of white rice supplied to a fowl of 1,200 to 1,400 grams 

 weight should preserve it in nutritive equilibrium. From experimental observa- 

 tion 3.5 grams of polishings had been shown to accomplish this result. This can 

 scarcely be regarded merely as a coincidence, but its exact significance and im- 

 portance can not yet be estimated. 



Fowls receiving nothing but water do not develop polyneuritis, while 

 fowls receiving only polished rice and water do. No satisfactory ex- 

 planation of this observation has as yet been obtained, but further 

 researches are in progress. Meanwhile the amount of phosphorus esti- 

 mated as phosphorus pentoxide contained in a given rice may be used 

 merely as an indicator of its liability or otherwise to produce beriberi. 



We are greatly indebted to Mr. B. J. Eaton, chemist in this institute, 



