74 
Eucalyptus corymbosa, Sm., Fl. Austr. iii. 256. Bloodwood. This 
tree, the foliage of which does not contain any volatile oil, yields a 
g b 
gum in la 
fluid of the consistence of treacle. It often becomes imprisoned 
between the layers of wood, where it gets hard, and may be broken 
out in quanti t varies from being soluble in water to complete 
tity. 1 : 
insolubility in water and alcohol. 
corymbosa as in that of Angophora lanceolata ; and no further deposit of 
it is formed after the first one is filtered off. Addition of HCl toa 
¢ 
tion... ; . 
f boiled, the bulky mass of the precipitate collapses 4 little 
Alcohol then takes the phlobaphene (from the corymbosa tannin) out; 
metarabin and ellagic acid are left. Cold KOH takes the ellagic a8 
out of the metarabin, which dissolves when boiled in KOH. _ oy) 
There is a bright blood-red colouring phlobaphene present m roe 
tan-resin gum of E. corymbosa, which shows the following reactions 7 
. on addition 
of ammonia. KOH, greenish-brown. Cyanide of potassium, be 
a,CO,, greenish-brown. Copper acetate, greenish-brow2 : 
Ammon. molybdate in HNO,, dark-brown and greenish. 
soda, green. d nitrate, greenish-brown precipitate. 
es dt : 
tannin gives reactions similar to those of the gums belonging t 
gummy and the ruby groups. ee 
_ The phlobaphene produced from corymbosa tan-resi0 gum * 
boiling in dilute HCI looks darker than that of Angophora lanceolals 
there is a changeable amount of residue left undissolved 2 
depending on the presence of arabin or metarabin and of insoluble 
phlobaphene in the exudation. The insoluble part amounts ie presen times 
to 45°0 pee ene sometimes there is only 250 per cent. of it. matter 
OF Ven: 1086. Out of this residue alcohol dissolves a resinous © 
holding some tannin embodied in its substance. The tannin 60% 
