170 PLANT ANATOMY. 
before mucilage makes its appearance in the respective cells, 
there are found starch granuies, which afterward disappear—a 
circumstance which very probably stands in definite relation to 
the formation of mucilage. 
We shall also meet with a transformation and solution of 
cellulose later on, when we come to the consideration the origin 
of cell fusions. In the formation of vessels, sieve-tubes and 
lacticiferous ducts, namely, a resorption (solution) of the trans- 
verse walls consisting of cellular substance takes place. Besides 
this process of solution, there also occurs, during the formation 
of the lysigenic balsam ducts (see also under “ Receptacles for 
Secretions ”), a transformation of the cellulose into secretions. 
Thus, for example, the membrane may become converted into 
resin ’ (see Index references to the latter). Such a transforma- 
tion appears also to be the case in the formation of the resin of 
Polyporus officinalis Fries. 
With the varieties of gum and mucilages are also connected 
the pectic substances, the knowledge of which is still very 
incomplete. 
In close connection with the bodies which have here been 
treated of stands lichenin® (lichen-starch, amylo-cellulose), a 
carbo-hydrate deposited in Cetraria islandica, in Usnea, Parme- 
lia and Cladonia. AccordingtoBerg, the lichenin of the first- 
named lichen, the /celand moss, is a mixture of two substances, 
one of which is colored blue by iodine and is dissolved by 
chloride of zinc and ammoniacal oxide of copper.? 
} The formation of resin can take place: 1. As a true secretion through 
proper organs of secretion. 2. By the liquefaction of the outer walls of 
certain cells, 3. By a metamorphosis of the entire cell-wall and con- 
tents of the cell (lysigenic and pathologic receptacles for resin). 4. By 
a transformation of certain constituent bodies, increasing the resin 
formed according to 2and3. (Compare Hanausek, ‘‘ Jahresbericht der 
_Handelsschule in Krems,” 1880). See also subsequent references under 
«« Receptacles for Secretions.” : 
? From lichen. 
*Jahresbericht der Pharmacie, 1873, 21. Compare Flickiger, 
*‘ Pharmakognosie,” second edition, 273, and ‘‘ Ueber Stérke und Cellu- 
lose,” in Archiv der Pharm., 196 (1871), 27. 
