300 
PROCEEDINGS OE SECTION B. 
partly, and ellagic acid crystallises out by evaporating the solution. 
Ferric acetate stains the powder deep blue and then black. Chloroform 
dissolves this precipitated powder, and on evaporation sets down long 
crystalline needles of ellagic acid (at 750 enlargement). In cold alcohol 
the Angophora gum seems at first to be entirely soluble, but after a 
short time a white deposit resembling arabin is put down, which, when 
tested, proves to be nothing else but ellagic acid amounting to 4 per 
cent, of the gum. 
In finding much ellagic acid in the Angophora gum we are induced 
to look for ellago-tannic acid as the mother substance, and to compare 
the reactions of a solution of Angophora gum with those of Myro- 
balans and Divi-divi, which hitherto were thought to be the richest 
source of ellagic acid. 
Now, copper acetate makes a light-brown precipitate in fresh 
Angophora solution, not so light as with Mvrobalans, but much lighter 
than with gallo-taunic acid. Copper sulphate makes a slight green 
precipitate (gallo-taunic acid no change), and on addition of ammonia 
a light-brown precipitate is formed. Limewater makes a yellow 
precipitate, turning purple like Myrobalans (gallo-tann., pale precip. 
turning blue). Ammon, molybdate in nitric acid produces a dirty 
yellow or dark-greenish precipitate like Divi-divi (gallo-tann., yellow). 
Lead nitrate gives a yellow-brown precipitate. These reactions show 
decidedly that Angophora gum contains a tannate most allied to that of 
Myrobalans and Divi-divi. 
A watery solution of Angophora lanccolata gum, when filtered from 
the first deposit of ellagic acid, continues to make fresh deposits of 
this, until the ellago-tannic acid is quite exhausted, and until only the 
phlobaphcne-yielding tannin is left, so that an old watery solution of 
A. lanceolata is stained only pink by II OK, whereas a fresh solution 
gets yellow and pink in a mixture. 
By boiling a watery solution of Angophora gum with dilute 
hydrochloric acid, ellagic acid (insoluble in spirits) is obtained, showing 
clearly the presence of ellago-tannic acid in the gum. Three times as 
much of a red phlobaphene besides, soluble in alcohol, goes to the 
bottom after cooling. It is derived from a second tannin present in the 
Angophora gum. As much more of this second tannin is contained in 
the Angophora gum, it can be isolated by the fractioned addition of 
cold hydrochloric acid to a gum solution. The ellago-tannic acid, 
mixed with the other tannin (Angophora-tannin) is thrown out 
first, and the rest consists of a nearly^ pure solution of Angophora- 
tannin, yielding only phlobaphene if boiled with the hydrochloric acid. 
Borax and soda as well as cyanide of potassium and caustic potash 
produce now the same pinkish colouration in this Angophora gum 
solution, after the elimination of the ellago-tannic acid, as we used to 
see in the gums of the two previous groups. Copper acetate gives 
now a dark precipitate ; limewater a dark precipitate, more bluish 
than with siderophloia gum. Ferric salts give a blue-black, ammon. 
molybdate in nitric acid a dark-brown colouration or precipitate. By r 
shaldng the Angophora solution with acetic ether after elimination 
of the ellago-tannic acid, the Angophora-tannin can be obtained 
pure. By" dry distillation it yields pyro-gallol stained beautifully 
purple-blue by caustic potash, and purple-violet by limewater or 
