New York Agricultural Experiment Station. 277 

 The two methods yield practically the same results. 



SEPARATION OF ORGANIC AND INORGANIC PHOSPHORUS. 



Iwanow^^^ has lately studied the changes occurring in the 

 organic phosphorus combinations during the germination of vetch 

 (Vicia sativa) and has reached the conclusion that there is a 

 gradual decrease of organic phosphorus with corresponding in- 

 crease of the inorganic forms as germination proceeds. The seeds 

 were germinated in the dark. The method of separation used by 

 Iwanow was as follows: 5-7 grams of the material was warmed 

 on the water bath 10-15 minutes with 100-150 cc. of i per ct. acetic 

 acid. After cooling, the precipitated proteid matter was separated 

 by filtration through a small flannel filter and washed with water 

 until about 500 cc. filtrate had been collected. For the determina- 

 tion of the inorganic phosphorus an aliquot from the 500 cc. was 

 taken and precipitated directly with molybdate solution. 



Zaleski/"^ working independently and on- the same problem, 

 evolved an almost identical method. This investigator recom- 

 mends the use of either a i per ct. acetic acid or 0.2 per ct. hydro- 

 chloric acid solution, as the extracting reagent. As will be shown 

 later in both of these methods, the cleavage action on soluble 

 nucleins of the nitric acid contained in the molybdate solution is 

 not sufficiently taken into account. It is true that Zaleski recom- 

 mends that no extra nitric acid be added, he himself using only 

 the ordinary molybdate solution. 



Kossel '^^ working on muscle extracts has used a mixture of 

 tannin and 5 per ct. hydrochloric acid as the precipitant of 

 proteids containing phosphorus. 



Araki -^^ has recently used this method, somewhat modified, in 

 his studies of the decomposition of nucleic acids by enzymes.. 

 The method of Araki was as follows : 2 grams of a salt of nucleic 

 acid was dissolved in 40 cc. of water and to this the enzyme was 

 added. This solution was then diluted with an equal volume of 

 water, 4 grams of sodium acetate added and tannin so long as a 

 precipitate continued to be formed. The filtrate from this precipi- 



(1) Ber. deut. hot. GeselL, 20: 366 (1902). 



(2) Ber. deut. bot. GeselL, 20: 426 (1902). 



(3) Zeit.f.physiol. Chem., 7: 9 (1885). 

 (*) Zeit.f.physiol. Chem., 38. 84 (1903). 



