ETIOLOGY OF BERIBERI. 41 



The amido-nitrogen is low in tiie iiighly milled rices which 

 are always low in phosphorus pentoxide ; and high in rice 

 polishings, beans, and momjos which contain a considerable 

 proportion of phosphorus pentoxide. This is an interesting 

 parallel to the work of Parrozzani(.'3) who showed that the amido- 

 nitrogen and total nonproteid nitrogen in many grains com- 

 monly used as food are both proportional to the content of 

 organic phosphorus. The fact is also interesting in the con- 

 sideration of a suitable index of the beriberi-preventing char- 

 acter of certain rices. The amount of phosphorus pentoxide 

 has hitherto been used as such an indicator with general satis- 

 faction, but we have recently examined samples of undermilled 

 rices which retained almost the entire pericarp and which 

 undoubtedly will prevent beriberi, and yet these rices on anal- 

 ysis were shown to contain a percentage of phosphorus pentox- 

 ide as low or lower than that in some specimens of highly 

 polished rice which have been analyzed by the same chemists. 

 There can be no doubt that the character of the soil may effect 

 very materially the phosphorus content of rices as it does in 

 the case of other grains. Chamberlain, Bloombergh, and Kil- 

 bourne(5) have shown that the percentage of potassium present 

 in a rice is satisfactory as an indicator, and it now appears 

 that the amount of amido-nitrogen may also be equally reliable. 



These observations pointed to the possibility that some non- 

 proteid nitrogenous substance, like arginin or asparagin, might 

 be the neuritis-preventing substance which is present in rice 

 polishings. As is well known, Takaki considered the disap- 

 pearance of beriberi from the Japanese navy to be due to the 

 increase in nitrogenous constituents in the ration. Although 

 this theory of nitrogen starvation has long been discredited, 

 the possibility that there might be a deficiency in a particular 

 nitrogenous compound, such as amido-nitrogen, has not to our 

 knowledge been considered. This possibility was further em- 

 phasized by a study of two dietaries used in Bilibid prison in 

 Manila (6). The first ration (Table IV) was in use from about 

 December 1, 1901, until October, 1902, during which time there 

 were 5,448 cases of beriberi with 229 deaths. Beriberi com- 

 pletely disappeared after the institution of the second ration 

 (Table V). The two rations are given in full, together with 

 their proximate principles, and it will be seen that while there 

 was no appreciable change in the amount of albuminates in 

 the two dietaries, the amount of amido-nitrogen, calculated as 

 asparagin, was only 5.84 in the first ration and was increased 



