280 
THE AUSTRALASIAN JOURNAL OF PHARMACY. 
I found no trace of either benzoic or cinnamic acids in the gum. Having 
ascertained the presence of tannin by appropriate tests, I set about establishing 
its identity or otherwise with any of the known varieties of tannic acids, with 
the result that it was found to be very nearly allied to, if not identical with, 
quercotannic acid, giving the blue-black precipitate with ferric chloride which is 
readily distinguished from the dirty green precipitate produced by kinotannic 
acid, the variety existing in the B.P. kino ( Pterocarpus marsupium.) 
In estimating the amount of tannin present I employed two methods of 
estimation, the first of which consisted in percipitating tannate of copper with 
cupric acetate, drying, igniting, oxidising with HN0 3 , and weighing the oxide of 
copper ; then by calculation the amount of tannin necessary to form that oxide of 
copper can be determined. By this means the tannin present was found to be 9*91 
per cent. In this process, the precipitating, drying, and igniting should be done 
as quickly as possible, as quercotannic acid is one of the most unstable of 
tannins, and is liable to decompose during manipulation, which would give anything 
but true results. The second method was the skin process, about which it is 
unnecessary for me to go into details, as on 18th March last, Mr. Walter Ince 
read a paper before this Society fully describing the process, it being based 
upon the fact that raw hide will extract tannin from solution. I obtained as 
the result that the gum contained 10T5 per cent of tannin. 
It will be seen on comparing these two results that they very closely 
approximate, the difference being only 0*24 per cent. ; the quantity of tannin 
present may therefore be put down as 10 per cent. The tannin for qualitative 
investigation was obtained by percolating coarsely-powdered gum with cold 
water ; this tannin solution contained a little of the colouring matter of the 
gum, which was got rid of by precipitating the tannin with acetate of lead, 
and after well washing the precipitate excess of H 2 S was passed through it 
suspended in water ; this formed the insoluble lead sulphide, leaving the tannic 
acid in solution, and after boiling well to drive off the excess of H 2 S and 
filtering, a practically pure solution of the acid was obtained. 
The acid precipitated gelatin as a white precipitate, similar to gallotannic 
acid. Ho precipitation occurred when added to an aluminium salt, or to a 
solution of KSbC 4 H 4 0 7 ; with (NH 4 ) a C0 s a brownish flocculent precipitate 
was produced, soluble in excess and depositing on standing. 
On boiling a solution of the tannin with a little H 2 S0 4 for some hours, a 
red amorphous substance settled down on cooling ; this was found to resemble 
quercus-red, and when dried and fused with caustic potash gave evidence of 
phloroglucin and protocatechuic acid. The gum answers the test for kino given 
by Fliickiger and Hanbury, of giving a violet colour when a solution is shaken 
with reduced iron. 
I tried the gum as a varnish, employing as solvents turpentine, methylated 
spirit, and linseed oil, with the results shown ; the linseed oil and turpentine 
I believe practically dissolved nothing, but the methylated spirit has yielded 
a hard, smooth and transparent varnish. 
A discussion followed, in which the chairman, secretary, Messrs. Eastes, 
Farr, and Orange took part. 
One of M. Pasteur’s latest reports on his inoculations to the French 
Academy of Medicine is more encouraging than recent accounts would lead 
people to suppose. Out of 950 cases treated, only six have proved fatal. 
These include the four Russians bitten by a wolf. The subscriptions to the 
Pasteur Institute amount to nearly £'27,000. 
