CELL-CONTENTS AND FORMS OF CELLS. 187 



which arises from the cell-sap, is stained by corallin, and behaves 

 with reagents much like cherry-gum. The cells are either isolated 

 or occur in groups placed end to end, as in Veratrum viride. 



Raphides are found in relatively few drugs, as follows : 

 Cinnamomum, convallaria, cypripedium, ipecacuanha, phytolacca, 

 sarsaparilla, scilla, vanilla, and veratrum viride. 



V. CRYSTAL FIBERS. In quite a number of drugs a single 

 monoclinic prism or a rosette aggregate occurs in each of the 

 parenchyma cells adjoining the sclerenchymatous fibers, and to 

 this single longitudinal row of superimposed cells the name crystal 



FIG. 1 08. A, transverse section of hyoscyamus leaf showing monoclinic prisms of 

 calcium oxalate, also a twin-crystal; B, longitudinal section of glycyrrhiza showing a 

 crystal fiber, i.e., a row of superimposed cells, each containing a polygonal monoclinic 

 prism of calcium oxalate, the crystal filling the cell. Adjoining the crystal fiber is a group 

 of bast fibers on one side and some cells containing starch on the other. 



fiber has been applied (Fig. 108, B). Crystal fibers are typical 

 of the following drugs: Aspidosperma, frangula, glycyrrhiza, 

 hsematoxylon, hamamelis, Prunus serotina, quercus alba, quil- 

 laja, rhamnus purshianus, and uva-ursi. 



VI. MICRO-CRYSTALS are exceedingly small (about 0.2 to lo/* 

 in diameter), apparently deltoid or arrow-shaped, and so numerous 

 as to entirely fill the parenchyma cells in which they occur, giving 

 the cells a grayish-black appearance which readily distinguishes 

 them from other plant cells (Fig. 107, D). It has been sup- 

 posed that they are tetrahedrons, but they are probably sphenoids 



