INDIVIDUAL VEGETABLE CELLS. 31 



star-shaped, hour-glass shaped, disk-shaped, tubular, 

 many-sided, or of any other form. (Fig. 8.) 



9. The bioplasm within the cell-wall may be trans- 

 formed into a great variety of formed material, mak- 

 ing special cell-contents. These may be solid, as col- 

 oring matter, starch, crystals, and resin ; or fluid, as 

 oil and gum, or solutions of sugar or tannin. The 

 most important of these substances is called Chlvro 

 ptytt) (Gr. chloros, green; phyllon, a leaf,) or 

 the source of the green color of plants. It is com- 

 posed of a peculiar coloring matter intimately united 

 with separate particles of bioplasm, which, under the 

 influence of sunlight, causes the absorption of car- 

 bonic acid gas from the air, which is necessary to 

 nourish the plant. Starch is also an important prod- 

 uct of vegetable cells, even more widely distributed 

 than chlorophyll. It seems to be stored up in the 

 cells as a reserve food-material for the use of the new 

 cells which are subsequently formed, hence it oc- 

 curs in large quantities in seeds, 

 bulbs, and tubers. (Fig. 9.) 



Crystals of oxalate of lime 

 often occur in cells, as well as 

 acid substances and alkaloids^ 

 like strychnine, quinine, etc., 

 dissolved in the cell-sap. 



It is remarkable that such 

 different materials as cellulose, Fig. 9. 



