254 PLANT ANATOMY. 
form of tissue (Fig. 176). From these cells surrounding the 
intercellular balsam-passage (secerning cells, epithelium) the 
volatile oil, and the resin dissolved therein, penetrate through 
their walls into the passage. 
A canal which has been formed in the manner just described, 
by the parting of cells from each other, is termed schizogenic.' 
In the larch, in addition to resin receptacles of this kind, 
lysigenic passages are also found (page 248). 
A ramification of those passages which more closely concern us 
here is not perceptible on a longitudinal section through them, 
Fic. 178.—Longitudinal section from the bark of Radix Sumbul (Ferula seu Eury- 
—angium Sumbul); r, medullary rays; 1, phloém; b, oil-passage (the parenchyma lying 
beneath it being visible). : 
so that they do not represent a vascular system, like the latex- 
tubes of many plants (e. g., Figs. 163-165). The more simple 
form of the resin-passages is in harmony with the manner of their 
formation, although this does not exclude the passages from oc- 
casionally attaining a considerable length (Fig. 176), as in the 
_ sumbul root (Fig. 178), in Rhizoma Imperatorie, or, as already 
_ mentioned, in Copaifera, and presumably also in Dipterocarpus.* 
| Byitw I cleave, and yévos production. 
___ * Fliickiger, “‘ Pharmakognosie,” p. 86. 
