THE NITROGEN OP PEOCESSED FERTILIZERS. 11 



resemble cholesterin. When dry the crystals were light, had a 

 satiny glossy appearance, and were not easily wet again with water, 

 They were extremely soluble in hot water and quite easily soluble 

 in cold water. Leucine was further identified by the fact that it 

 sublimed, 1 and by the crystalline form and solubility of the copper 

 salt, 2 and by its two color reactions with quinone, 3 red with a solution 

 of leucine and quinone and violet when in addition sodium car- 

 bonate was used. 



Tyrosine. — The methyl alcohol solution of the copper salts was 

 evaporated to dryness, and the residue taken up in water. The 

 copper was removed with hydrogen sulphide and the solution was 

 boiled with animal charcoal. After filtering, the solution was con- 

 centrated and long thin silky needles began to separate. These 

 needles, which closely resembled tyrosine, were filtered off, and the 

 filtrate further concentrated, when another crop of needles was 

 obtained. These were filtered off and added to the first fraction and 

 were then extracted with boiling 70 per cent alcohol. The crystalline 

 residue was recrystallized from water a number of times and dried 

 on a porous plate. This compound crystallized in the stellate groups 

 of long slender silky needles which are characteristic of tyrosine. 

 These crystals were relatively insoluble in cold water, 4 very insoluble 

 in cold 90 per cent alcohol, easily soluble in hot water, and were 

 tasteless, colorless, and infusible. The compound was further 

 identified as tyrosine by the formation of the copper salt, which was 

 rather insoluble in cold water and fairly easily soluble in hot water, 

 by the fact that a solution of the compound gave a red color when 

 boiled with Millon's reagent, 5 and that a sulphonic acid prepared from 

 the compound gave a violet color with ferric chloride. 6 



Purine bases. — Five pounds of base goods were boiled up with 10 

 liters of water, filtered, neutralized and concentrated to a volume of 

 about 2,500 c. c. The solution was made strongly alkaline with 

 sodium hydroxide and the purine bases were precipitated with 

 Fehling's solution and dextrose according to the method of Balke. 7 

 The supernatant liquid was decanted from the copper precipitate 

 and this was washed, until free from alkali, with a solution of sodium 

 acetate, by repeated decantations. The precipitate was filtered, 

 freed from sodium acetate by washing with alcohol, and the copper 

 removed by suspending the precipitate in water and treating it with 

 hydrogen sulphide. After filtering off the copper sulphide the solu- 

 tion was concentrated and the purine bases reprecipitated by means 



i Schwanert, Liebig's Ann., 102, 224 (1857). 



^ Hofmeister, Liebig's Ann., 189, 16 (1877). 



3 Wurster, Centrlb. Physiol., 2, 590 (1889). 



* Erlenmeyer and Lipp., Liebig's Ann., 219, 161 (1883). 



» Millon, Compt. rend., 28, 40 (1849); Lassaigne, Ann. Chem. Phys. (2) 45, 435 (1830). 



« Piria Liebig's Ann., 82, 252 (1852). 



' Jour, prakt. Chem. [2], 47, 537 (1893). 



