SACCHARINE AND ASTRINGENT EXUDATIONS OF GREY GUM. 181 
crystals exactly like aromadendrin in this respect. By decompos- 
ing with water the crystalline compound formed by hydrobromic 
acid in boiling acetic acid, the substance is obtained in a pure 
state and quite free from inorganic salts. 
I have already obtained data in regard to this colouring matter 
which enable me to state that this substance gives every indication 
of being a valuable dyeing material, and probably belongs to the 
quercetin group of natural dyeing substances. It forms yellowish — 
to slightly orange crystalline compounds in boiling acetic acid 
with mineral acids; alkalis dissolve it with a yellow to orange 
colour; nitric acid dissolves it very energetically to a bright 
crimson colour, aromadendrin becoming crimson only after a short 
time with this reagent: in alcoholic solution ferric chloride gives 
an olive-brown colour not altered by heating: the lead precipitate 
in alcoholic solution is yellowish to orange: it is almost insoluble 
in cold water and not very readily in boiling water: it is soluble 
in a small quantity of boiling alcohol, not readily in cold alcohol : 
it is practically insoluble in cold ether, and only slightly soluble 
in boiling ether, and it does not appear possible to remove it from 
an aqueous solution by ether; it differs in this respect from aroma- 
dendrin which is readily and entirely removed from aqueous solu- 
tion by ether: it dyes alumina mordanted calico a bright yellow: 
when heated in fused alkali to 200° C. for half an hour the pro- 
ducts of decomposition are found to be protocatechuic acid and 
phloroglucinol. 
Many of these reactions are those of quercetin itself, and from 
the above results, particularly its forming crystalline compounds 
with mineral acids in acetic acid, and its dyeing properties, there 
appears little doubt but that this yellow substance is allied to 
quercetin. This product has perhaps great commercial possibilities 
because the raw material can be obtained in any quantity, and is 
at present unutilized, and being in the form of leaves, can be 
readily dried and powdered, and the dyeing material can be easily 
Separated if required, so that tannin bodies need not interfere ae 
any way. E. macrorhyncha is found over a large portion of the 
