UNORGANIZED CELL-CONTENTS. 
27 
MONOCLINIC PRISMS AND PYRAMIDS OF CALCIUM 
OXALATE. 
Monoclinic prisms and pyramids are also widely 
distributed and are frequently so modified in form 
that they are of an elongated or irregular hexagonal 
shape. The crystals of this group are sometimes mis- 
taken for silica, owing to the fact that in some in- 
stances the lumen of the cell is completely filled by 
the crystal, and the inner wall, having the contour of 
the crystal, it is impossible to determine whether the 
crystal is affected by the use of hydrochloric acid. It 
should be stated in this connection that silica never 
occurs as a cell-content in sharp angular crystals, but 
occurs either in more or less ellipsoidal or irregular 
hollow masses, or in somewhat solid, irregularly 
branching masses. 
VEGETABLE DRUGS CONTAINING MONOCLINIC PRISMS OR 
PYRAMIDS OF CALCIUM OXALATE. 
The following drugs are characterized by mono- 
clinic prisms, and are grouped according to the size 
of the crystals. 
(a) Crystals not more than 10// in diameter: Coca, hyoscyamus 
and uva ursi. 
(i) Crystals not more than 20 ft in diameter : Calumba (in stone 
cells only), frangula, grauatum (rosette aggregates also occur), 
hamamelis, quercus alba (rosette aggregates also occur), rhamnus 
purshiana and senna. 
(c) Crystals not more than 30 n in diameter: Cardamomum, 
eucalyptus, gelsemium, pimenta (occasional), prunus virginiana, 
quassia (cryptocrystalline crystals also occur), vanilla, viburnum 
opulus, viburnum prunifolium (occasional), and xanthoxylum. 
( d ) Crystals not more than 100 or 200 // in diameter: Krameria 
(about 100 fi) and quillaja (35 to 200 //). 
CRYSTAL FIBERS. 
In quite a number of drugs a single monoclinic 
prism occurs in each of the parenchyma cells adjoin- 
