364 Report of the Department of Chemistry of the 



the author concludes that his results are the only correct ones; 

 owing to his superior method of isolation and purification, " purer " 

 products had been obtained and he proposes the formula C12H41O42P9 

 as the correct one for phytic acid or inosite phosphoric acid. 



We have already shown 7 that the above author is in error in respect 

 to the composition of the acid in cottonseed meal. The carefully 

 purified and many times recrystallized barium salts which we pre- 

 pared from the acid from cottonseed meal had the composition of 

 acid barium salts of inosite hexaphosphate, CeH^C^PeBas and 

 (CeHnC^Pe^Ba?. The free acid prepared from these salts corre- 

 sponds to inosite hexaphosphate, C6H18O24P6, and not to an acid of 

 the formula C12H41O42P9. 



The silver precipitates which we prepared from the above inosite 

 hexaphosphate were pure white amorphous substances and very 

 slightly sensitive to light. We showed, 8 however, that these silver 

 precipitates are not homogeneous salts of inosite hexaphosphate but 

 mixtures of more or less acid salts of the above acid. 



In again taking up the investigation of the organic phosphoric 

 acid compounds of wheat bran we have first of all critically repeated 

 our former work. The results completely confirm those reported 

 in our earlier paper. 9 We then repeated the work of Rather follow- 

 ing his method of isolating the crude acid as closely as possible. 

 The acid preparation obtained in this way was divided into two 

 parts: One portion was used for the preparation of the silver salt 

 as described by the above author; the other portion was transformed 

 into the barium salt and purified in accordance with our previous 

 method. 



The barium salts which were obtained in this way were found to 

 agree very closely in composition with those previously reported, 

 viz.: C2oH 4 50 4 9P9Ba 5 and not with salts of the acid C12H41O42P9. 



The silver precipitates which were obtained from the crude acid 

 varied in composition according to the method of preparation but 

 in one case the substance had approximately the composition stated 

 by Rather. A simple examination of these silver precipitates 

 quickly revealed the fact, however, that they were not " pure 

 homogeneous salts " of an organic phosphoric acid of the formula 

 C12H41O42P9 as claimed by the above author, but that they were 

 largely contaminated with inorganic silver phosphate — varying 

 from 42 to 90 per ct. 



In our first report 10 on this subject we called attention to the fact 

 that wheat bran extracts contain relatively much inorganic phos- 



iJourn. Biol. Chem. 17:141 (1914); and N. Y. Agric. Exp. Sta. Tech. Bull. 32. 

 (1914). 



8 Ibid., p. 149. 



•Journ.Biol. Chem. 12:447 (1912); and N. Y. Agric. Exp. Sta. Tech. Bull. 22. 

 (1912). 



10 Loc. cit. 



