BARKS—HERBS. 63 
removed, such a bark then consists at last almost exclusively of 
the inner bark, as, e. g., the Cinchona calisaya and Coto bark. 
The inner bark is intersected by medullary rays (bark rays) 
which, upon a transverse and longitudinal section, are often 
plainly perceptible, without being magnified, as delicate lines. 
The fracture of barks [that is, the appearance of a fractured 
surface], which is frequently a very useful characteristic, on the 
other hand, chiefly depends upon the fibres in the secondary 
bark (bast-bundles), upon the degree to which the elements of 
the same are thickened, and upon the form of combination of 
their prosenchymatous cells. 
It is to very long, soft, and intertwining bast-fibres that Cortex 
Mezerei (Mezereum), as likewise the bark of Radix Althee, owe 
their eminently fibrous character. The Cinchona barks are brit- 
tle, because their strongly thickened bast-tubes remain short and 
are usually isolated. The outer surface of Ceylon cinnamon 
admits of the ready recognition of the long, wave-like bast-bun- 
dles, which here and there intersect each other. 
The cork (outer bark), is usually rejected, since it contains 
no active constituents, If it be thin, it often remains preserved 
on the bark, and can afford good means of distinction. Of the 
cambium, itis but seldom that remnants are preserved, since its 
cells possess very delicate walls. 
Occasionally entire annual plants, or those of a few years’ 
growth (without the roots) are employed. In pharmacognosy, 
these are then spoken of as herbs. “3 : 
Herbs (Herba). These are the leafy shoots of phenogams 
which, beside the leaves and tenderer portions of the stem (the 
main axes are often removed) may possibly contain individual 
flowers and fruits, or the entire inflorescence and collection of 
fruits. There are no reasons for the exclusion of these struc- 
tures which often accompany the leaves, and frequently it would 
be virtually impossible, as, ¢. g., in the case of Herba Centaurtt, 
Herba Meliloti, Herba Serpylli, ete. ee 
Not unfrequently, the form of ramification of the shoots is of 
diagnostic importance in the case of herbs. The different systems 
of ramification may, therefore, be considered here ina few words, 
