of Phosphorus in Animal and Vegetable Tissues. 473 



formation is a progressive one, the extent of the reaction appearing 

 to have some relation to the time employed. The inorganic phos- 

 phates are first affected, then lecithin, the organic phosphorus being 

 much more slowly converted into the orthophosphate. 



According to Liebermann,* the phosphorus found in such com- 

 pounds as nuclein and nucleic acid is in the form of monometa- 

 phosphate, but Kosself has thrown doubt on the results on which 

 this view is based, and he claims that the facts point rather to the 

 occurrence of other anhydrous forms of phosphoric acid in these 

 compounds. Jolly J has inferred from his experiments that in 

 organic compounds of phosphorus the latter does not occur in the 

 unoxidised metalloid (" metallo'idique non oxyde integre ") form. 

 Milroy has found that in the digestion of nuclein compounds with 

 trypsin, some of the phosphorus is set free as orthophosphoric acid, 

 but the greater part (89'08 91/63 percent.), occurring in an organic 

 form, does not possess the characters of metaphosphoric acid, for its 

 solutions may be boiled a long time without producing an increase 

 in the amount of the ortho compound present. 



As the nitric- molybdic reagent reacts only with the ortho form of 

 phosphoric acid, it is obvious that the organic phosphorus in the 

 tissues must be put in the condition of orthophoshoric acid. Lilienf eld 

 and Monti treated the fresh tissues with baryta water or sodic car- 

 bonate, in order to set the phosphorus free as phosphate, which was 

 then demonstrated as the phospho-molybdate ; but, as Liebermann || 

 points out in the case of yeast nuclein, the baryta compound is only 

 after long boiling, or, after heating with acids, converted into the 

 orthophosphate. The action of the baryta must, in part at least, be 

 to change the structure of the elements, and it is not certain, there- 

 fore, that in all cases the ortho compound formed should be in the 

 structures where the phosphorus originally existed. This, and the 

 fact that the sodium compound first formed by sodic carbonate, being 

 soluble, may diffuse from its original situation, render this method 

 of doubtful value in localising phosphorus in tissue elements. These 

 observers, however, claim that the nitric acid in the molybdic 

 reagent has the property of gradually converting the phosphorus 

 compounds into the orthophosphate, and they allowed fresh prepara- 



* "Nacbweis der Metapbospborsaure im Nuclein der Hefe," 'Arch, fiir die 

 gesam. Pbysiol.,' vol. 47, p. 155, 1890. 



t " Ueber die Nucleinsaure," ' Verb. Pliysiol. Gresell. zu. Berlin,' ' Arch, fiir 

 Anat. und Physiol.,' Phys. Abth., 1893, p. 157. 



" Kecherches sur le phospliore organique," ' Comptes Kendus,' vol. 126, p. 531, 

 1898. 



" Ueber die Eiweiss-Verbindungen der Nucleinsaure und Tbymlnsaure und 

 ihre Beziebung zu den Nucle'inen und Paranucleinen," ' Zeit. fiir Pliysiol. Cbemie,' 

 vol. 22, p. 307, 1896-97. 



II Loc. cit. 



