INTERCELLULAR SECRETIONS, 251 
Correa, Ruta, Dictamnus),’ of the leaves and fruits of Citrus, 
and of Jaborandi leaves. 
Thus, for example, in the very large oil-spaces in the rind of 
the fruit of species of Citrus, a solution of the cell-walls is dis- 
tinctly perceptible.* This is, perhaps, still more the case in the 
trunks of Copaifera,? in which the balsam passages attain 
an enormous development. These trees contain the copaiva- 
éalsam in canals which are as much as an inch in diameter, and 
which often traverse the entire trunk, so that a single one, after 
being bored, is capable of yielding balsam by the pound. In 
the so-called ‘‘ gummosis,” the membranes become converted 
into gum (compare page 166, Fig. 78). 
In the Sterculiacez, lysigenic (protogenic, page 263) gum-pas- 
_ Sages are found.‘ 
The lysigenic passages, like the schizogenic, which will be 
described directly, may be either dermatogenic, that is, produced 
by the participation of epidermal cells (Citrus, Dictamnus, 
Amorpha), or they may be formed under the epidermis, deeply 
in the interior (interior glands in a more restricted sense). 
The secreting space of the lysigenic passages is always com- 
pletely closed. 
The intercellular receptacles for secretions, or the so- 
called oil-passages and balsam-passages, belong neither to the 
true cells, nor to the tubes produced through the fusion of cells, 
nor to the passages of lysigenic origin. 
The formation of these receptacles, which are found in the 
Myrtaceer (Hucalyptus, Figs. 127,128, Myrtus, Eugenia, Pimen- 
ta), in the Leguminose (Amorpha, Hymenea, Trachylobium), 
in the Umbellifere, Composite, and Conifere, in Ovalis, 
Lysimachia and Myrsine,* admits, in the families of the Um- 
1 Here also in the interior of hairs, Sachs, ‘‘ Lehrbuch,” p. 93. Mar- 
tinet, loc. cit, De Bary, loc. cit. Fig. 22. 
?Sachs, ‘‘ Lehrbuch der Botanik,” 1874, p. 92, 
* Karsten, Botan. Zeitung, 1857, p. 316. 
4Trécul, Compt. rend., 1862, p. 315.—Ledig, Botan. Centralb., 1881, 
vi., p. 387. 
5 Von Héhnel, in the investigation cited on page 250. 
