QUEENSLAND NATITE ASTRINGENT MEDICINES. 
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whitish deposit insoluble in water and alcohol, and consisting of 
nothing else than ellagic acid, which is dissolved by caustic potash, 
with intense yellow colouration. 
(3.) Siderophloia gum contains 1‘5 per cent of gallic acid. For 
its determination the gum tannin is precipitated with antimon. tartar 
and chloride of ammonia. The filtrate is shaken with ether, the ether 
evaporated, and the gallic acid collected. As gelatine, like powdered 
hide, throws the gallic acid down in presence of gum, it is not reliable for 
the elimination of gum tannin. It can be assayed in a 10 per cent, 
solution of gum, freed from gum tannin by a method used by me, and 
based on F. Jean’s method, to determine tannin from the volume of 
the gum solution used up to render a solution of iron chloride opaque. 
Cyanide of potassium cannot be used for the detection of gallic acid 
in those gums on account of the phlobaphene giving a similar reaction. 
(1.) The colouring matter of the siderophloia gum is a soluble 
phlobaphene or anhydrite of the gum tannin. We can call it gum 
phlobaphene. It is precipitated by alkaloids, gelatine, acetate of lead, 
ferric salts, &c. In very dilute solutions, especially on a photographic 
opal plate, it shows its proper colour as a very delicate pink, condensed 
in more concentrated soluiions to a light and then to a darker brown. 
It is very similar to the colouring matter of the Malabar kino, though 
this never shows such delicate pink tints even if diluted to the highest 
degree. The derivation of the gum phlobaphene from the gum tannin is 
distinctly shown in forming blue precipitates with diluted ferric acetate. 
Kino-red gives green colourations. Limewater does not throw out the 
colouring matter of the siderophloia gum ; it only lightens its pink colour 
more, especially between the precipitated gum-tannate of lime. If 
now a ferric salt is added, the phlobaphene falls out with a delicate blue 
colour (turning brown). Alkalies make the pink phlobaphene lighter, 
changing it more to vermilion, especially carbonate of soda. Cyanide 
of potassium acts still in a higher degree on the colouring phlobaphene, 
imparting to it exactly the same colour as it does to gallic acid 
solution, and easily leading to mistakes. A permanent vermilion 
colour, by addition of potass, cyanide, never indicates gallic acid ; the 
reaction is due to the gum phlobaphene. Malabar kino-red shows the 
same reaction to alkalies, and very likely the error in the books that 
it contains gallic acid is due to the vermilion colouration of the kino- 
phlobaphene, which by ferric salts is turned green. It must be noted 
that all light-coloured precipitates in siderophloia gum caused by 
gelatine, cinchonine, lead acetate, &c., are stained pink and, on addition 
of potass, cyanide, vermilion through the presence of this phlobaphene. 
In the fresh gum there are only traces of insoluble phlobaphene. 
Eucalyptus crebra , F. v. M. — The bark of this tree looks very 
much like that of E. siderophloia. The gum exuded by it cannot be 
recognised from that of the common Brisbane ironbark, having the 
same chemical composition and the same properties as E. siderophloia. 
E. resinifcrciy Sm. — This tree is called by timber-getters “ Jimmy- 
low, ” and its habitat nearest to Brisbane is the paddock adjoining 
Mr. Williams’ Nursery, near Kuraby. It is not one of the ironbarks, 
but has a greyish, fibrous stringy bark, from which a gum is exuded 
resembling closely that of the two trees previously described. 
