Jan. 6,1919 Determination of Acidity and Nitrogen in Wheat 13 



(3) The temperature at which the extraction was made was found to 

 have but little influence upon the hydrogen-ion concentration. The 

 higher temperatures give an extract of but slightly higher concentration. 



(4) The duration of the digestion period did not influence the hydrogen- 

 ion concentration. The average hydrogen-ion concentration when the 

 extraction was made for 5 minutes, 30 minutes, and i hour was the same 

 as when the extraction was made for 8, 16, and 24 hours. 



(5) But while the hydrogen-ion concentration of the extract shows no 

 increase with the duration of the digestion, the quantity of NI20 barium 

 hydroxid necessary to add in order to change the concentration to a 

 definite point was greater in amount and within certain limits propor- 

 tionate to the duration of the digestion. 



(6) The substances produced when v/heat is digested in water are not 

 ionized until an alkali has been added. The amount of these substances 

 produced bears a definite relation to the time and temperature used in 

 digestion. A limit, however, is soon reached, and this limit is reached 

 sooner at the highest temperature. 



(7) The amino nitrogen as determined by the Sorensen formaldehyde 

 method is all extracted in two hours at 40° C. 



(8) At 20° C. the amount of phosphorus in the extract precipitated by 

 magnesia mixture averages about half of the total. At 40° practically 

 all of the total phosphorus is converted into forms that are precipitated 

 by the magnesia mixture. 



(9) The hydrogen-ion concentration of the water extract of wheat is 

 definite in amount. This concentration is not changed during the 

 extraction in proportion to the time. The reason for this is that the 

 conditions for ionization are not present until an alkali is added. When, 

 however, this is added, ionization takes place and the amount of standard 

 alkali necessary to add in order to lower the hydrogen-ion concentration 

 to a given point bears a proportionate relation to the temperature and 

 duration of the digestion period. 



