284 Report of the Chemical Department of the 



acid for forty hours the inorganic estimation showed but 

 0.088 per ct., while the total soluble phosphorus was 1.26 

 per ct. We found it impossible to filter extracts of linseed 

 meal and consequently could only prepare such extracts 

 by decantation. This of course gave us a distinctly turbid solu- 

 tion. On precipitating w'ith molybdate solution an unusually 

 large flocculent precipitate resulted, difificult to filter and wash. It 

 redissolved readily in ammonia. Also in the case of alfalfa a very 

 large flocculent precipitate was formed on adding the molybdate 

 solution. Later, working with sprouted grains, we estimated in 

 one case as inorganic phosphorus 0.0118 gram magnesium pyro- 

 phosphate. This precipitate after ignition was unusually white. 

 On dissolving it in dilute nitric acid and reestimating the phos- 

 phorus we weighed but .0017 gram of magnesium pyrophos- 

 phate. Tliis is an extreme case, but it indicated that where we 

 have a large flocculent proteid precipitate with our molybdic acid, 

 soluble again in ammonia, there can be formed on the addition 

 of magnesia mixture insoluble proteid-magnesia combinations 

 convertible to magnesium oxide on ignition and weighed as mag- 

 nesium pyrophosphate. With this precaution in mind we rede- 

 termined the inorganic phosphorus in alfalfa and linseed meal. 

 On the first weighing as magnesium pyrophosphate they showed 

 respectively .0072 gram and .0107 gram. On dissolving in dilute 

 nitric acid we weighed as magnesium pyrophosphate .0006 gram 

 and .0005 gram respectively. These figures are equivalent to 

 .008 per ct. inorganic phosphorus in alfalfa and .007 per ct. in 

 linseed meal, figures we still believe due to errors of manipulation. 



experiments with the use of tannin and sodium acetate. 



Since Araki has used this method as a means of separating 

 nucleic acids from solutions containing organic and inorganic 

 phosphorus, it was thought that it might be applied to our work. 

 Extracts were made with 0.2 per ct. hydrochloric and i per ct. 

 acetic in the usual way. To 200 cc. of the extract neutralized 

 with ammonia, 12 grams of sodium acetate was added and then 

 a solution of tannin until no further precipitate was formed. The 

 mixture was then diluted to 250 cc, filtered through a dry filter 

 and in 200 cc. the total phosphorus (supposedly inorganic) deter- 



