42 RESEARCHES ON THE NITROGENOUS NON-ALBUMINOUS 
°>357 gram, of the substance, dried at xio°C. 
gave 0,0281957 gr. N. in the form of ammonia. 
Calculated for C5H11NO3. 
N 7-73°/o- 
Actually found. 
7-9°°/o- 
The slightly high percentage of nitrogen actually found 
might perhaps be attributed to a slight admixture of leucine 
which is constanly found associated with tyrosine. The 
substance in question was, beyond any doubt, tyrosine. The 
total quantity of tyrosine obtained amounted to about 2,5 
grams ; hence the quantity actually contained in the material 
under examination must have been far greater, since not only 
a part of the substance would remain undissolved, but also 
some would be retained in the lead compounds, whilst another, 
perhaps, still greater part might have escaped the precipitation 
by mercuric nitrate. 
The filtrate from tyrosine crystals yielded, upon further 
concentration, a second crop of impure tyrosine. The concen¬ 
trated solution was then allowed to slowly evaporate over 
sulphuric acid. After a few days, large shining transparent 
prismatic crystals were formed, amounting to about 1 gram. 
Their characteristic crystalline form, a priori, pointed out that 
the crystals were asparagine. The aqueous solution not only 
threw down the characteristic copper compound when boiled 
with freshly precipitated cupric hydroxide and allowed to cool, 
but also disengaged ammonia gas when boiled with caustic 
potash. The determination of “ water of crystallization ” in 
the crystals specially purified, gave the following result : 
0.200 grms. of the crystals lost 0,02392 gr. 
at io5 c C. 
Calculated for C4.H8N2O3 + H2O Actually found 
H2O 12 . 00 0 1 0 n.g6°/ 0 . 
The liquor separated from asparagine crystals served for 
the examination of xanthine and hypoxanthine bodies. For 
this purpose, the solution, after having been diluted with twice 
its own volume of water, was treated with an ammoniacal 
