PYRIMIDIN GROUP. 415 



carnin in which case it would contain less hydrogen than given 

 above. 



The free base is very easily soluble in water and has a strong 

 alkaline reaction. It forms minute needle-shaped crystals and melts 

 with decomposition at 239°. 



The nitrate on evaporation yields radiating crystals and is also 

 precipitated in stellate masses of needles by the addition of alcohol 

 to a hot aqueous solution of the salt. It is dextro-rotatory and melts 

 with decomposition at 211°. 



On boiling with copper carbonate it yields a copper compound 

 (CgHj^N^Oj .CuO) which is difficultly soluble in cold, rather easily 

 soluble in hot water from which it crystallizes in characteristic six- 

 sided plates. It decomposes without melting at 220°. 



Cjrtosin, Cj^Hg^Nj^O^ -I- SH^O, was obtained by Kossel and Neu- 

 mann by the decomposition of adenylic acid (from thymus glands ) 

 by heating with 20 percent, sulphuric acid in a sealed tube at 150° ; 

 also by the action of water at 170°. The yield is about 2 per cent. 

 It forms rectangular plates, often with blunted corners. On slow 

 separation the crystals may attain a length of,a centimeter. The 

 water of crystallization is expelled at 100°. It is easily soluble in 

 hot water, from which it separates on cooling ; difficultly soluble in 

 alcohol ; insoluble in ether. 



It forms well crystallized salts. Thus, the sulphate forms needles ; 

 the chlorid is easily soluble and appears in prisms. The nitrate, 

 platinochlorid, and aurochlorid likewise crystallize easily. A brick- 

 red precipitate forms in even very dilute acidulated solution by the 

 addition of potassium bismuth iodid. Silver nitrate produces a pre- 

 cipitate which is increased by addition of a little ammonia, but is 

 dissolved gradually by an excess, especially on warming, but it reap- 

 pears in crystalline form on cooling. 



The picrate, C^JIj!ijP^.2C^TI^'Np„ is difficultly soluble and 

 crystallizes in yellow needles. 



It is evident that cytosin is still subject to investigation. In some 

 respects it suggests a relationship to the pyrimidin bodies. At all 

 events the formula as given is more complex than might be expected 

 by comparison with the other well studied products of nucleins. 



PYRIMIDIN GROUP. 



Two substances belonging to this group have been isolated from 

 nucleinic acids by hydrolysis. Although they are neither basic nor 

 acid in character, yet their relation to the purin bodies and hence 

 to nuclein is such as to render their consideration necessary. They 

 have been regarded as antecedents of the purin bodies, rather than 

 as decomposition products of these substances. Nevertheless, it 



