298 
PROCEEDINGS OF SECTION B. 
The percentage of Eucalypto-arabin and gum tannin is the same 
too, varying in water and solubility according to the weather and the 
age of the gum. Of course, there is no kino-tannic acid contained in 
the gum, and the percentage as given by Staigcr for the tannate is 
much too high. I found by different methods, including Lowenthal, 
only 24 per cent, of gum tannin stained blue by ferric acetate, 
and yielding pyro-gallic acid by dry distillation. Eucalypto-arabin is 
present at 50 percent. The rest is water. The colouring phlobaphene 
is a little more red-brown than that of the ironbarks, showing a little 
less the delicate pink colour of the gum phlobaphene. 
Eucalyptus saligna , Sin. — The tree is called grey gum. The bark 
is cast off very slowly, and the stem of the tree seldom looks clean. 
It yields very little gum ; and this, as Mr. Maiden first observed, 
belongs to the gummy group. It agrees in all essential parts with the 
gum of siderophloia , only it seems to contain a little more of gum 
tannin, showing to me as much as 30 per cent. The colouring 
phlobaphene is not different from that of siderophloia , and the tannin 
vields pyro-gallol by dry distillation. 
The gums of the whole group are of high medicinal value, 
especially for the organs of digestion and for the skin. They must 
never be administered in alcohol, though they are dissolved by it very 
easily if they are soaked in water first. They must be administered 
for internal purposes, as a fresh 10 per cent, solution of selected 
gum, of which 6 oz. can be taken in twenty-four hours. Scale 
preparations, as Dr. Joseph Bancroft recommended for purification 
of the gums, must never be made on tin. The tannate dissolves some 
•of the metal, and makes insoluble and even poisonous precipitates 
when dissolved again. For external use a still stronger watery 
solution of treacle consistence is wanted. It will be found to be a 
splendid remedy for many things if used properly. 
For tanning purposes the gums containing such a high amount of 
eucalypto-arabin are very inferior to other tans. The leather can lie 
in a strong solution of the gum for many weeks without being tanned 
at all, and without being able to take the eucalypto-tannic acid out of 
its combination with the eucalypto-arabin. The skin might even 
undergo a kind of maceration, and turn bad, when still a high 
percentage of tannin is left in the solution combined with the arabin, 
as I am convinced bv many experiments. 
II. The ruby group of Mr. Maiden is represented in the 
Moreton Bay district by the gums of Eucalyptus hcemastoma , 
E. acmenioidcs , E. eugenioideSy E. pilularis, and E. tereticornis. All 
these gums contain between GO and 70 per cent, of eucalypto-tannic 
acid, 7-8 per cent, of eucalypto-arabin, and 15-20 per cent, of water. 
The rest consists of impurities. 
(1.) The eucalypto-arabin occurs in these gums mostly as 
metarabin, and settles to the bottom with the impurities. It is easily 
dissolved by caustic potash solution, and precipitated again by acetate 
of copper. The “ insoluble phlobaphene” of some authors is this 
eucalypto-arabin united with eucalypto-tannin. 
(2.) The tannin of this group agrees with that of the gummy 
group in every respect. It yields pyro-gallol by dry distillation, and 
has nothing to do whatever with kino-tannic acid. All reactions are 
