124 Report of Department of Animal Industry of the 



stable when pure and when no mineral acids are present. Moreover, 

 Contardi^ reports that when phytin is heated in an autoclave with 

 pure water for several hours to a temperature of 200° C. only very 

 small quantities of inosite could be isolated. 



In order to determine if inosite is present in determinable quantity 

 100 gm. of commercial phytin in the form of the acid calcium salt, 

 which had been imported from Europe and kept in the laboratory 

 for several years, was shaken up with 1 liter of water, filtered at 

 once and washed with water. The filtrate was precipitated with 

 barium hydroxide, again filtered and the excess of barium precipi- 

 tated with carbon dioxide, and the filtrate from the latter evaporated 

 on the water-bath. In the very slight residue which remained, 

 consisting mostly of barium carbonate with a trace of barium chloride, 

 no trace of inosite could be detected by the most painstaking method 

 of isolation. Of the same phytin 100 gm. was dried to constant 

 weight at 115° C. and was then treated in the same manner. Even 

 here no trace of inosite could be obtained. Subjecting to the same 

 treatment 50 gm. of the same phytin, after previously mixing with 

 0.5 gm. inosite, resulted in the recovery of 0.4 gm. inosite. 



This proves that phytin is by no means so easily split as Starken- 

 stein claims. The results in his case may have been due to other 

 causes besides mere drying at 100° C. 



The same author (loc. cit.) also states that when phytic acid is 

 precipitated with ammoniacal magnesia mixture it is not the mag- 

 nesium ammonium compound which is formed, but only the diffi- 

 cultly soluble magnesium phytate. This is an error. Under these 

 conditions the previously mentioned penta-magnesium ammonium 

 phytate, C6Hi2027P6Mg5(NH4)2, is formed. 



For the free phytic acid Posternak- proposed the empirical formula 

 C2H8O9P2 which he considered tof^iave'lthe following constitution: 



Hi 

 CH0-P0(0H),1 



/ 



(0\ 



\ 



CH0-P0(0H)2 



H 



which finds expression in the name " anhydro-oxymethylen di- 

 phosphoric acid." 



As is well known the free acid, as well as its salts, is easily split 

 under the influence of dilute mineral acids into inosite and ortho- 

 phosphoric acid. This fact and the discovery by Neuberg^ that 



' Atti R. Accad. dei. Lincei, Eoma (5), 18, I: 64. 



2 Co77ipt. Rend. 137: 439. 



' Biochem. Ztschr. 9: 551 and 557. 



