VIII. B, 5 Gibson: Salt Mixtures and Beriberi 355 



Odaki " also obtained a phosphotungstic acid precipitable pro- 

 tective substance from the alcoholic extract of rice polishings. 

 Vedder -* has not succeeded in isolating this substance in experi- 

 ments as yet reported. In the same paper, Vedder reports 

 incidently experiments on fowls with rice and Rohmann's salt 

 mixture which are negative. The paper appeared while the 

 present work was under way. Vedder and Clark -'' suggested 

 the occurrence of at least two "vitamines" in the alcoholic ex- 

 tracts of the rice polishings to account for the types of polyneu- 

 ritis gallinarum which they distinguished. 



Osborne and Mendel ^° have recently published a comprehen- 

 sive study of the role of the individual proteins in nutrition. 

 They have followed the growth changes in young rats when fed 

 on a single highly purified protein, along with fat, carbohydrate, 

 and a salt mixture having the same composition as the salts in 

 milk. The experiments show that normal growth can occur only 

 when the protein component of the diet is complete as regards 

 the amino-acids obtained on cleavage. Mere maintenance, or 

 even nitrogen starvation, results when an incomplete individual 

 protein is fed. The food in Osborne and Mendel's experiments 

 contains no purines or nucleic acid. In the case of the vegetable 

 proteins, such as edestin, there is no organic phosphorus, yet 

 normal gro^vth was obtained even with a diet consisting of 

 edestin, starch, sugar, and salts. There is apparently no physio- 

 logical necessity for organic phosphorus, lipoid, or organic iron 

 (in more stable form than the citrate). 



According to Osborne and Mendel, then, provided sufficient 

 calories are fed as fat or carbohydrate, but two dietetic factors 

 are necessary — a chemically complete protein and a physiologi- 

 cally balanced salt mixture. It would seem that the develop- 

 ment of polyneuritis in fowls ought to be prevented when white 

 rice is fed with properly balanced mineral ingredients, provided 

 the rice protein is nutritively adequate. 



Deficiency in the protein may be excluded. The chief protein 

 of the rice ^^ is oryzenin, a glutelin. Suzuki, Yoshimura, and 

 Fuji ^- have determined some of the amino-acid cleavage prod- 

 ucts of this protein. Their analyses indicate that the protein is 



" Biochevi. Zeitschr. (1912), 43, 89. 

 '« This Journal, Sec. B (1912), 7, 412. 

 '" Loc. cit. 



"Zeitschr. f. physiol. Chem. (1912), 80, 307; Journ. Biol. Chem. (1912), 

 12, 81; ibid. (1912), 473; ibid. (1912), 13, 233. 

 " Kajiura, Biochem, Journ. (1912), 6, 171. 

 "'Journ. College Agr., Imp. Univ. Tokyo (1909), 1, 77. 



