104 HISTOLOGICAL BOTANY. 



either scattered or aggregated. These are Crystals (Fig. 

 121). of calcium oxalate. 



( Chlorophyll-corpuscles. 

 SPECIAL CONTENTS OP THE CELL-l Starch-grains. 



[ Crystals, etc. 



If thin sections of oily seeds as those of the Togoma (Ricinus communis) 

 and Tonasu are examined under the microscope, there will be seen 

 numerous rounded granules. These are only modified portions of the 

 protoplasm and bear the name of Aleurone-grains. 



In the cells of the Potato tubers, there are often found cubical bodies 

 of albuminous matter. Although they bear a close resemblance to true 

 crystals, they are readily distinguished from the latter by the fact that 

 they swell up when treated with various reagents. These albuminous 

 bodies are called Crystalloids. Crystalloids are also found within some 

 aleurone-grains as those of the Togoma and Tonasu. 



If thin sections of the corolla of the Tampopo are examined under the 

 microscope, numerous yellow granules will be seen. 



If the root of the Ninjin is examined in the same way, orange-red 

 rectangular plates Or rhombs will be found, 



1. CHLOROPHYLL-CORPUSCLES. 

 If green leaves are cut into small pieces and put in a 

 vessel containing alcohol, the green colouring matter or 

 Chlorophyll is readily extracted by the solvent, and the 

 pieces become whitish. Now if thin sections of these pieces 

 are examined under the microscope, there will be seen 

 colourless corpuscles instead of green ones. These colour- 

 less corpuscles are specialized portions of the protoplasm. 

 Each chlorophyll-corpuscle is therefore composed of a 

 colourless granule of the protoplasm distributed by a small 

 quantity of chlorophyll. The corpuscles are mostly sphe- 

 rical, elliptical, or ovate (Fig. 118) ; but in rare cases they 

 are spiral-shaped as in Spirogyra (Fig. 119.a), star-shaped 

 as in Zygnema (Fig. 119.b), etc. They often conbain minute 

 granules which are the first formed starch-grains. 



