TITER -CELT, 23 
parts of the plant is very considerable, e.g. 25 per cent 
of the whole weight of potatoes is starch, and 70 per 
cent of wheat grains. 
Calcium Oxalate crystals are found in empty cells in 
most plants. One crystal of quite large size may be 
formed belonging usually to the tetragonal system, or 
a number of small crystals may fill the 
cell. In other cases, especially among 
lilies and orchids, the calcium oxalate 
assumes the form of bundles of needle- 
shaped crystals called RapHripEs (fig. 
12). eSome botanists state that these 
needle-like crystals serve to ward off 
the attack of caterpillars and snails, 
etc. . 
Fats and oils occur in the form of 
drops in the cytoplasm, and many 
medicinal preparations are obtained by 
pressing the fat and oil from the plant, 
and subsequently purifying it. Castor wg, 19—Cell of 
oil, oil of cloves, etc., are obtained in 4/08. retusa, 
ar ; showing Ra- 
this way. Tannin is found in the cor-  phides. (From 
: Thomé’s ‘ Text- 
tex in the form of a highly concentrated book of Bot- 
solution filling the vacuoles. a a 
Aleurone or proteid grains are of a nitrogenous nature, 
and are formed from cell sap rich in albumin. They 
assume the form of round grains, or, sometimes, irregu- 
larly shaped bodies. In the aleurone grains are fre- 
quently found crystals of albumin, and sometimes of 
calcium oxalate. In cereals the aleurone grains are 
found in a layer of cells just below the pericarp. 
