260 . PLANT ANATOMY. 
walls were to disappear, the figure of an oil-passage produced 
by resorption would be obtained. Such a solution of the trans- 
verse walls does not occur, however, in Fructus Conii. 
The spaces which have just been considered contain either 
volatile oil (Myrtaceze), which in drugs is often already more or 
less resinified, or a mixture of volatile oil and resin, or finally 
resin itself. : 
Resin, which is free from volatile oil, is also met with in 
Lignum Guaiaci and in Lig. Quassie in the form of brittle, 
Fic. 184.—Transverse section through Fructus Conii; a, albumen of the seed; }, © 
embryo; ce, commissural surface; e, epidermis; m, tissue of the fruit casing; ¢’, inner- 
most layer of the latter; ¢, layer of cells containing volatile oil and coniine; o, vitte; v, 
ribs (costz), traversed by fibro-vaScular bundles. . 
shapeless masses. In these two plants the resin first makes its 
appearance at a later period (at an advanced age) in ordinary 
wood-cells and vessels of the heart-wood; it thus shows a deport- 
ment similar to that of physiological gum (see page 166), with 
which it also appears to be chemically related (see also page 
264). 
Dees ‘a a microscopical examination, the resin and oil, especially 
when they occur mixed with each other as a balsam, escape from — 
