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 / 'eratrum viridc. 



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. 108. 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, 

 haematoxylon, hamamelis, Priinus serotina, quercus alba, quil- 

 laja, rhamnus purshianus, and uva-ursi. 



VL Micro-crystals are exceedingly small (about 0.2 to 10 m 

 in diameter), apparently deltoid or arrows-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 



