LOCATION OF 7HE ALKALOIDS. 39 
cially at the point of the bast-wedges, on the boundary of the outer 
bark, they occur only very much scattered (Plate VII, A). 
The steve-tudes in the Cinchona barks of commerce are usually 
very much collapsed, and therefore can only be isolated with con- 
siderable difficulty. 
While in the young barks the soft bast predominates, this pro- 
portion becomes gradually changed in favor of the greater or less 
development of the sclerotic fibres. The bark of the same species 
must, therefore, in accordance with its age, present a very dissimi- 
lar appearance, and consequently afford but a deceptive criterion 
for the purpose of diagnosis, even when within certain boundaries 
the specific peculiarity is maintained. 
The barks of the individual Cinchonas present some prominent 
distinctions, especially with regard to the more or less considerable 
number of stone-cells, as in some barks such sclerotic cells are en- 
tirely wanting. The barks furthermore differ from each other with 
relation to the arrangement of the bast-fibres. The considerable 
thickness, the simple, spindle-shaped, compact form, and the not 
very large number of these bast-fibres, impart to the Cinchona barks 
a definite character, which is not possessed by the barks of the 
most closely related species that have as yet been examined. 
That, however, intermediate representatives are not wanting, is 
illustrated by the “Cinchona rosa,” as described on page 49. 
Among themselves the Cinchona barks display, indeed, great uni- 
formity; and in many figures, such as are given by Berg’, for ex- 
ample, no decided characteristics are rendered prominent, when 
they are compared with each other, 
SECTION VIII. 
CONTENTS OF THE TISSUE. LOCATION OF THE ALKALOIDS. 
Most of the cells of the true, as also of the false Cinchona barks 
which are not lignified, or not completely so, with the exception of 
those of the cork cambium and the crystal ducts, are so abundantly 
filled with coloring matter, which also penetrates the walls, that 
their other constituents, as also their structure, is only plainly per- 
ceptible when the coloring matters are to some extent remove 
an operation which is best effected by ammoniacal alcohol. Even 
the cork frequently contains Cinchona-red, and in the innermost, 
1 A description of them is given by Miller, Baumrinden, pp. 132, 138. _ : 
2 In the work mentioned under Section XVIII. With regard to the peculiarities of 
structure of the Cinchona barks in comparison with other Rubiacee, see Méller, Baum- 
vinden, pp. 132, 138. 
