286 Report of the Chemical Department of the 



but at the same time allows complete precipitation of inorganic 

 phosphates. 



In one experiment, when to a solution containing .0413 gram 

 of inorganic phosphorus estin:r.ted as magnesium pyrophosphate, 

 was added .500 gram of nucleic acid prepared from wheat bran, 

 and the solution then subjected to the above method, the recovery 

 was .0439 gram — a gain of .0026 gram by cleavage of the nucleic 

 acid present. This .0026 gram of magnesium pyrophosphate 

 calculated in percentage of phosphorus on a 2 gram sample is 

 equal to .036 per ct. It can be readily seen, then, that estima- 

 tions of inorganic phosphorus giving results as high as .036 per 

 ct. in solutions rich in soluble organic phosphorus can easily be 

 accounted for as coming by cleavage of organic phosphorus 

 combinations. 



Attempts have been made to remove the interfering proteids 

 by precipitation w-ith neutral ammonium molybdate in solutions 

 cooled to 18° C. and in the presence of but i cc. 1.20 nitric acid 

 in 250 cc. volume. This did bring about partial removal, bu-t 

 on warming the solutions with the addition of the extra i cc. of 

 1.20 nitric acid, necessary to precipitate the inorganic phosphorus, 

 there was generally a further precipitation of proteid matter and 

 consequent interference. 



experiments with germinated grains. 

 Since Iwanow^^^ and Zaleski/^) working independently, have 

 shown that during the germination in the dark of vetch and lupine 

 a marked decrease in organic phosphorus with corresponding in- 

 crease in inorganic forms appeared to take place, it became of 

 interest to carry on similar work, using our own method for the 

 separation of inorganic phosphorus. Both these workers used 

 the ordinary molybdate solution containing free nitric acid in their 

 inorganic determinations. For our work we selected corn, oats 

 and wheat. These were germinated in pure quartz sand in the 

 dark for periods of one and two weeks. At the end of these 

 periods the grains were dried at 60° C, separated from the adher- 

 ing sand and finely ground. After exposure to the air for a few 



(1) Ber. dent. Bot. Gesell., 20 : 366, 1902. 



(2) Ber. (ieut. Bot. Gesell., 20: 426, 1902, 



