THE NITROGEN OF PROCESSED FERTILIZERS. 11 
resemble cholesterin. Wlien 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 
subUmed,^ and by the crystalHne form and solubihty of the copper 
salt,^ and by its two color reactions with quinone,^ 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 
boded 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 boding 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 sdky needles which are characteristic of tyrosine. 
These crystals were relatively insoluble in cold water,^ 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 tyrosiae by the formation of the copper salt, which was 
rather msoluble in cold water and fairly easily soluble in hot water, 
by the fact that a solution of the compound gave a red color when 
boded with Millon's reagent,^ and that a sulphonic acid prepared from 
the compound gave a violet color with ferric chloride.^ 
Purine bases. — Five pounds of base goods were boiled up with 10 
hters 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.'^ 
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 washmg with alcohol, and the copper 
removed by suspending the precipitate in water and treatmg it with 
hydrogen sulphide. After filtering off the copper sulphide the solu- 
tion was concentrated and the purine bases reprecipitated by means 
1 Schwanert, Liebig's Ann., 102, 224 (1857). 
2 Ilofmeister, Liebig's Ann., 189, 16 (1877), 
3 Wiirster, Centrlb. Physiol., 2, 590 (1889). 
< Erlenmeyer and Lipp., Liebig's Ann., 219, IGl (1883). 
» MiUon, Compt. rend., 28, 40 (1849); Lassaigne, Ann. Chem. Phys. (2) 45, 435 (1830). 
« Piria Liebig's Ann., 82, 252 (1852). 
Uour. prakt. Chem. [2], 47, 537 (1893). 
