128 Report of Department of Animal Industry of the 



stein. It is, however, difficult to understand why the hexa-phos- 

 phoric ester was not obtained by this method. The only explanation 

 that can be offered is that under the conditions of these experiments 

 it is not stable. 



One reason alleged by Starkenstein for considering phytin a 

 pyrophosphate is based upon its giving a white precipitate with 

 silver nitrate. This is certainly a characteristic reacton of pyro- 

 phosphates. Yet the tetraphosphoric ester gives a pure white 

 precipitate with the same reagent. As the ester cannot be in the 

 form of a pyrophosphate the fact that phytic acid gives the same 

 colored silver compound is not necessarily an indication that it 

 represents a pyrophosphate compound. 



The phytic acid used in these experiments was prepared from 

 products obtained from two different sources. The starting material 

 in one case was a calcium phytate imported from Europe; the other 

 was a crude natural magnesium organic-phosphorus compound 

 extracted in this country and kindly supplied us by Dr. Carl S. 

 Miner of Chicago. 



As shown by the analyses of the carefully purified salts and of 

 the free acid, these two preparations were identical and they were 

 also identical with the product described as phytic acid by Pos- 

 ternak and other investigators. 



EXPERIMENTAL PART. 



TRI-BARIUM PHYTATE. 



The commercial phytin was purified for analysis by means of 

 the barium salt. 30 gm. calcium phytate was dissolved in a small 

 quantity of 0.5 per ct. hydrochloric acid, diluted to about 2 liters 

 with water and a concentrated solution of 30 gm. barium chloride 

 was added. The precipitate was dissolved without filtering by 

 the addition of just sufficient dilute hydrochloric acid. It was 

 then precipitated by adding barium hydroxide to faintly alkaline 

 reaction. The mixture was then acidified with acetic acid and after 

 standing over night was filtered and well washed in water. It was 

 re-precipitated in the same manner three times. After finally 

 filtering and washing in water the substance was dissolved in about 

 1 liter of 0.5 per ct. hydrochloric acid, filtered and the filtrate pre- 

 cipitated by adding a like volume of alcohol. After repeating this 

 operation the substance was filtered, washed free of chlorides with 

 50 per ct. alcohol and finally washed in alcohol and ether and dried 

 in vacuum over sulphuric acid. 



The product so obtained was a light, perfectly white semi-crystal- 

 line or amorphous powder. Placed on moist litmus paper, it showed 

 a strong acid reaction. It is very slightly soluble in water, slightly 

 soluble in acetic acid and readily soluble in mineral acids. 



For analysis the substance was dried at 130° C. 

 0.2728 gm. substance gave 0.0352 gm. HoO and 0.0643 gm. CO2. 

 0.2763 gm. " " 0.1749 gm. BaS04 and 0.1675 gm. MgaPaOT. 



0.1909 gm. « " 0.1206 gm.BaSOi and 0.1154 gm.MgzPaOi. 



