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SELECTED ARTICLES, 
rent in the simple oil, but resides in a peculiar volatile acid 
principle, which may be detached. 
^' 2. Passing next to the Lump or Cahe Gamboge^ it must 
appear evident, that the composition of this variety will vary 
much according to its quality. At least from what has been 
said above of its commercial history, it must either vary much, 
or we must separate from this sort all the kinds often mixed 
with it, and vaguely known in trade by the name of Coarse 
Gamboge. The finer qualities of it usually called Cake or 
Lump Gamboge by druggists, appear from what I have seen, 
to be tolerably uniform. It is met with in amorphous masses, 
weighing two or three pounds, and upwards, if unbroken. 
It presents outwardly no striated marks of fibres. It contains 
visible fragments of wood, and sometimes twigs of consider- 
able size. It is not dense, smooth in texture, and easily 
frangible, like the Pipe variety, but full of little air-cells, less 
easily broken, and also much more difficult to reduce into 
fine powder. Its fracture is not conchoidal, rather splintery, 
and quite free from any glimmering lustre. Its colour, 
however, is much the same with that of Pipe Gamboge j its 
taste and odour are the same; and it very readily forms, with 
the wet finger, a smooth, bright Gamboge-yellow emulsion. 
Possibly the finer sorts which approach Pipe Gamboge in 
price, may also more nearly resemble that variety in external 
characters than has been here laid down; but I have not met 
with any such specimens. True Pipe Gamboge, however, it 
must be remembered, is often met with in the form of cakes, 
owing to several pipes or cylinders having been firmly agglu- 
tinated while soft.* 
" The chemical composition of Cake Gamboge is also mate- 
rially difierent. It is not, like the Pipe variety, entirely 
dissolved by the successive action of the two solvents, sul- 
phuric ether and cold water. About eleven per cent, of 
♦ Cake Gaaiboge boiled in fine powder with water, forms an emulsion ; 
which is rendered deep green by tincture of iodine ; while an emulsion 
of Pipe Gamboge, similarly prepared, merely becomes somewhat tawny. 
