426 CHEMISTRY OF THE PROTEIDS CHAP. 



Alsberg 1 finds the nucleic acid of the spermatic fluid of Lota 

 vulgaris to be identical with the nucleic acid prepared from salmon- 

 melt : 



By the action of dilute mineral acids one-half of the purin-bases 

 may be removed from the salmon-nucleic acid, while the other half 

 remains firmly united. Alsberg has given the name of hemi-nucleic 

 acid to a compound possessing only one molecule of purin-bases for 

 two molecules of P 2 5 : 



C 35 H 51 N 9 15 + 2P 2 5 + 3H 2 0. 



The alkali-salt of hemi-nucleic acid differs from that of nucleic 

 acid in not being precipitated from dilute acetic-acid solutions by 

 chloride of copper or by hydrochloric acid. 



Stronger mineral acids, by their action on nucleic acid, give rise 

 to a mixture of hemi-nucleic acid, nucleotin-phosphoric acid, nucleotin 

 and Ia3vulinic acid. ' Nukleotin ' is a name which was first given by 

 Schmiedeberg to the nucleic -acid compound minus the phosphorus 

 and minus the nuclein-bases. Nucleotin, according to Alsberg, has the 

 composition C 30 H 42 N 40 13 , and contains 1 4 per cent of water, held in a 

 ' cement-like ' manner. Nucleic acid, when acted upon by barium 

 hydrate, gives rise to a saccharic acid, this latter being formed probably 

 from the same radical in nucleic acid which gives rise to Isevulinic 

 acid when nucleic acid is acted upon by mineral acids. 



Nucleic acid gives rise to the following dissociation-products : 



1. Phosphoric Acid 



It is a constant and characteristic dissociation-product of nucleic 

 acids. As to the probable manner of its linking, see p. 431; whether 

 ' plasminic acid,' a metaphosphoric acid found in yeast, is related to 

 nucleic acid is uncertain. 2 



2. Pyrimidin-derivatives 

 Three simple pyrimidin-derivatives of nucleic acid are known : 



1. Uracil or 2 '6 dioxy-pyrimidin. 



2. Cytosin or 2-oxy-6-amino-pyrimidin. 



3. Thymin or 2'6-dioxy-5-methyl-pyrimidin. 



1 C. L. Alsberg, Arch, f. exper. Path. 51. 239 (1904). 



2 A. Ascoli, Zeitschr. f. physiol. Chem. 28. 426 (1899). 



