: 
tannate of lime. If now the ferric salt is added, the pees 
falls out with delicate blue colouration. Al Ikalies Bit the 
gallic ac y lead to mistakes ae permanent ve 
colour, on addition of potassium cyanide to a gum Ss lution, never 
indicates gallic asi but pink phlobaphene. Dilute acids turn the pink 
kino gets more pas 
Besides the tannie acid and the colouring phlobaphene, all 
Eucalypt gums which are soluble in water contain arabin or meta tarabin; 
but in this respect a wide gap divides the gums belonging to diff 
apesic®: ore Eucalyptus into two groups, as Mr. Maiden - ‘the skill to | 
the high percentage eds per aes of inal contained in them. 
(See under A, this page.) 
The gums of "the second group (the “ruby group 
Maiden) are readily soluble in alcohol, and contain not more than 
A per cent. of arabin, present sometimes as metarabin. (See undet 
» page 
Some gums of both groups contain gallic — so 5 per cent); | 
but it might not Ae a constant constituent o ot them biel x” deter- : 
the wa acid down in presence 4 oe it cannot be u 
case for the elimination of the tannin. ‘The ga sins acid a : 
the volume used up to render a solution of iron opaq 
potassium is useless on account of the colouring phlobaphene. 
A.—Gums oF THE Gummy Grovr. 
The arabin contained in the gums of this group a epee 4 
cent. is not gelatinised or ¢ ted by ferric chloride: | 
different in this respect from the arabin of Acacia harpophy age q 
posita, Albizzia Toona, Grevillea robusta, ani from: the Fo 
contained in the gum resin of Araucaria Bidwilli and A. Cunningham 
m the arabin of ee as well as from that of 4. dea 
differs in some essential p tet! ‘ 
cacia arabin is ede and entirely pais out of @ a ff | 
solution b pono Pas or if only a few of NaCl geal 4 
drops of HCl are added. It is not altered by the “acid, and ©) 4 
ily in water “se. the acidulated alcohol is poured 0 dition of 
arabin, in opposition to this, falls out suddenly by the ad 
ange but it gets redissolved after some standing, 
HCl is added. On addition of mu ch HCI to the Sct i 
uae peg but its GA composition nS altered thro Baling 5 
process; it becomes insoluble in as 
