lO 



Journal of Agricultural Research voi. xvi, No. i 



PHOSPHORUS IN THE WHEAT EXTRACTS 



As previously mentioned, determinations were made of total phos- 

 phorus and of phosphorus precipitated by magnesia mixture. 



From each extraction mixture two portions of 50 cc. each, represent- 

 ing 5 gm- of ground wheat, were pipetted into beakers. Ten cc. of 

 concentrated nitric acid were added and boiled until all the organic 

 matter was destroyed, more nitric acid being added as needed. The 

 residue was used for the determination of phosphorus in the usual way. 



To two other 50-cc. portions of the extraction mixture there were 

 added 40 cc. of magnesia mixture, and after standing for 15 minutes, 

 25 cc. of concentrated ammonia. After a thorough stirring the beakers 



Fig. 4. — Graphs showing the production of amino nitrogen at different temperatures. 



were allowed to stand overnight, and the contents were then filtered and 

 the precipitate washed four times with 2 per cent ammonium hydroxid. 

 The precipitate was then dissolved in 40 cc. of dilute (i 14) nitric acid 

 and the filter washed with 100 cc. of hot water. The filtrate and vv^ash- 

 ings were then boiled, in order to destroy organic matter, and the phos- 

 phorus determination was completed in the usual way. For convenience, 

 this will be called inorganic phosphorus. Whether or not that is the 

 case may be questioned, and the merits of this method of determination 

 are not discussed here. We simply used this method as one best suited 

 to our purpose, and the results obtained (Table IV) are used for their 

 comparative value. 



