TANNINS, 139 
‘tannic acid, which is present in these malformations to the ex- 
tent of as much as seventy per cent, is remarkable as a specially 
distinct member of the family of tannic matters; at least the ex- 
ceptional cases in which it is supposed to have been elsewhere 
recognized (in the Myrobalans and in sumach) may still be re- . 
garded with doubt. 
There may be distinguished physiological and pathological 
tannic matter. The former is produced normally in the vital 
process of the plant (thus the tannins of barks,’ such as that of 
the oak, quebracho, and the willow). The pathological, on the 
contrary, is first produced in consequence of an external influence 
(the puncture of-an insect, etc.), that is, in the course of a mor- 
bid process (galls). Both forms are also chemically and physi- 
cally different. Skins are only tanned by the physiological tan- 
nin (as in the formation of leather). 
The contents of the cells which have so far been treated of, if 
we except inulin, may be regarded as the organized contents. 
Besides these, however, there appear a number of unorganized 
bodies in the cells of plants, which are dissolved in the cell-sap,. 
or deposited in the membranes, and which are not amenable to 
direct microscopical observation. 
In the cell-sap there are dissolved, for example, a portion of 
the inorganic salts, dextrin, sugar, plant acids—the cell-sap al- 
ways has an acid reaction—and tannic matters, many glucosides* 
and bitter principles (Aloé, Fig. 63), coloring matters, amides, 
etc.; in the membranes are deposited many alkaloids (quinine ?). 
The chief solvent of most of these substances, water, evapo- 
rates to a large extent upon drying the drugs.* How considerable 
its amount may often be is shown in a striking manner by many 
' Compare in this connection, F. von Hoehnel, ‘* Die Gerberinden, ein” 
monographischer Beitrag zur technischen Rohstofflekre.” Berlin, Op- 
penheim, 1880, 
_ * PAvuvs sweat, and 7605 likeness. 
* To this fact, as it appears, is referred the expression drug, German 
droge; the u, which is still frequently inserted in the latter word 
(drogue), is derived from the Romanic languages, which have appro- 
priated the word. Fliickiger, ‘‘ Geschichte des Wortes Droge,” in Archiv 
der Pharm., 219 (1881), 81. 
