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SELECTED ARTICLES. 
will allow of those tracts of woodland becoming personal pro- 
perty, this highly esteemed production of the new world will 
be swept from the country." What Condamine asserts is 
highly probable, that both old and young trees die from the 
scaling of the bark, whether they are cut down or not; but 
Bollus and Arrot assert the reverse: the former states that 
Cinchona trees may be frequently seen deprived of their bark 
without suffering any detriment; and the latter tells us that from 
18 to 20 years are required for a Cinchona tree to produce a 
new bark. When the trees are cut down, Mr. Stevenson tells 
us that the roots generally sprout, but " no trees of any large 
size grow up, for they are either smothered by the lofty trees 
which surround them, or else they are choaked by other 
young trees which spring up near them, and are of quicker 
growth.'' 
Physical properties of the Cinchona barks. — Under this 
head I propose to examine the structure, the quilling, the 
color, taste, and odor, the fracture, and the cryptogamic 
plants, found on the Cinchona barks of commerce. 
Structure. — Those barks known to druggists by the name 
of coated barks consist of the following parts — an epidermis, 
the rete mucosum, and cortical layers, (the innermost of which 
is termed the liber.) 
( a) Epidermis. — This is the most external portion of the 
bark, and is variable in its thickness. The barks of commerce 
are said to be coated {Cinchona cum cortice exteriore of Ber- 
gen,) when the epidermis is present, but when this is absent, and 
when also part or the whole of the next layer (rete mucosum) has 
been removed, such barks are called uncoated ( Cinchona nuda 
of Bergen.) As the epidermisis useless, or nearly so, in a medi- 
cinal point of view, uncoated barks are to be preferred, since 
the epidermis increases the weight of the bark, without adding 
any thing to its real value. In reference to this layer, there 
are several characters deserving of attention in judging of the 
quality of bark: thus Cinchona barks, with a whitish epidermis 
are, I believe, for the most part, inferior to those in which this 
layer is brown. But you must not mistake a whitish coating 
