New York Agricultural Experiment Station. 345 



ineal, oats and corn. We have, therefore, re-examined the com- 

 mercial phytin using some of the same preparation as before. 



After carefully purifying the barium salt of the substance we 

 found that it crystallized very readily and no difference could be 

 observed either in crystal form, composition or reactions, of the 

 salts prepared in this way, from the crystalline salts previously 

 referred to. All of these compounds are therefore identical and the 

 analytical data indicate that they are salts of the acid C 2 H 6 08P2 

 or C 6 Hi 8 2 4P6. 



The composition, as determined by analysis, of the free acid 

 prepared from the crystalline barium phytate also agrees more 

 closely with the above formulas than with the usual formula of phytic 

 acid, C6H24O27P6. The phosphorus was found too low in this case as 

 well as in the acids previously described. This, however, is undoubt- 

 edly due to the fact that the acid is largely hydrolyzed on drying. 



It appears very probable then that the organic phosphoric acid 

 described above and known as phytic acid is either inosite hexa- 

 phosphate, C 6 Hi 8 024P6, or else an isomer of the same. We have, 

 however, no direct information concerning the molecular magnitude 

 of the acid. 



We have endeavored to prepare a neutral ester of the acid with 

 which molecular weight determinations might be made, but so far 

 these attempts have failed. By acting on the silver salt of the acid, 

 suspended in absolute methyl alcohol, with methyl iodide, an ester 

 is formed but it apparently suffers partial decomposition in drying. 

 Moreover we have been unable to prepare a neutral silver salt. Only 

 acid silver salts have been obtained even from solutions of phytic 

 acid neutralized with ammonia. From such salts, naturally, only 

 acid esters could be obtained. 



As has been pointed out by Starkenstein, 6 which observation 

 we have confirmed, 7 apparently only one-half of the acid hydroxyls 

 of phytic acid are particularly reactive. Some of the acid hydroxyls 

 appear to be very weak. It is no doubt due to this fact that from a 

 neutral solution of ammonium phytate only acid silver salts are 

 precipitated with silver nitrate. 



Starkenstein 8 reported that the commercial phytin which he had 

 examined contained relatively large quantities of inorganic phosphate 

 and that it also contained free inosite and he concluded that the 

 substance undergoes spontaneous decomposition. He also found 

 that after drying the preparation at 100° the greater portion of the 

 phosphorus was present as inorganic phosphate. 



These results, so far as the formation of inosite on mere drying 

 is concerned, we could not confirm 9 in the phytin preparations 



6 Biochem. Zeitschr. 30:65, 1910. 



7 Journ. Biol. Chem. 11:475, 1912, and N.Y. Agr. Exp. Sta. Tech. Bull. 19, 1912. 



8 Loc. cit., pp. 59 and 60. 



» Journ. Biol. Chem. 11:473, 1912, and N.Y. Agr. Exp. Sta. Tech. Bull. 19, 1912. 



