Xeuman method 5 grains of material placed in a Kjeldahl 

 f.ask, 10-15 cc. of concentrated sulphuric- acid added, and the 

 mixture heated over a low Maine until well charred, when partly 

 cool add 5 to 10 grams of ammonium nitrate and continue heating 

 and adding ammonium nitrate until the mixture has heen completely 

 oxidized and decolorized. In the method as used concentrated nitric 

 acid was used to replace the ammonium nitrate and small amounts 

 added at a time until complete oxidation has taken place. On 

 cooling the solution was transferred to a 500 cc. graduated flash and 

 made up to the mark. An aliquot was taken for the determination 

 of total phosphorus by the molybdatc ; magnesia added. 



Separation of Inorganic from Organic Phosphorus 



The various methods as given for the separation of inorganic 

 from organic phosphorus in plant and animal tissue, the following 

 seems most probable as a staring basis. Iwanow 1 separated as fol- 

 lows, 5 to 7 grams of the material was warmed on a water bath 

 ten or fifteen minutes with 100 to 150 cc, of 1 per cent. 

 acetic acid. After cooling, the precipitated proteid matter was- 

 separated by filtering, and washing with water until about 500 cc. 

 filtrate had been collected for the determination of inorganic phos- 

 phorus. Ah aliquot from the 500 cc. was taken and precipitated 

 directly with molybdate solution. 



Zaleski 1 worked on the same problem hut independently evolved 

 an almost identical method. Zaleski recommends the use of either 

 a 1 per cent, acetic acid solution or a .? per cent, hydrochloric acid 

 solution as the extracting reagent. The cleavage action, as shown 

 later, was not sufficiently taken into account on the nucleins by the 

 nitric acid contained in the ammonium molybdate. This author 

 recommended that more nitric acid be added although he did not 

 use it himself. 



Kossefi. The author worked on muscle extracts and used a 

 mixture of 5 per cent, hydrochloric acid and tannin as a precipitant 

 of the proteids containing phosphorus. 



Aralift has recently used this method somewhat modified in his 

 studies of nucleic acid by enzymes. The method is as follows: 2 

 o-rame of a salt of niu-leic acid dissolved in 10 cc. of water and to 



1. Ber. deut. bot. Gesell., %0, 336 (1902). 



1. Ber. deut. bot. Gesell., 00, 426 1902). 



2. Zeits. Physiol.-Chem., 7, 9 (1883). 



3. Zeits. Physiol.-Chem., 36, 84 (1903). 



(5 



