WHAT FEEDING STUFFS CONTAIN 13 



ment. The cell walls are made up of a woody sub- 

 stance called cellulose. In green and growing 

 plants this cellulose is thin and tender, but as the 

 plant matures it becomes hard and woody. 



The roots, trunk, leaves and all other parts of the 

 plant are formed of cells. Plant food in the soil -is 

 made soluble in soil moisture, and by means of the 

 cells comprising the roots the soluble substances 

 are sucked in and carried in water to all parts of 

 the plant. The process by which this is done is 

 known as osmosis. The soluble plant food left in 

 the cells as the water passes along is met by the 

 carbon that has also been passed into the cells, not 

 through the roots, however, but through the leaves, 

 and thus brought together all building materials are 

 at hand for the manufacture of the plant compounds. 

 The master builder is the protoplasm tucked away 

 in the cells. No one knows just what protoplasm 

 is, but it represents life, without which there could 

 be no growth. 



Building Plant Tissue. The building work is 

 done in the plant cells, within whose tiny walls the 

 compounds are formed. These cells within which 

 this process is going on are either enlarged them- 

 selves or else the compounds are used for making 

 new cells. Every live, active cell contains proto- 

 plasm, the life principle. Herein is contained the 

 vital spark that makes all growth possible. 



Starch. When the soluble soil material or plant 

 food has been carried up through the long channel of 

 cells and reaches the leaves, it is brought in contact 

 with the carbon dioxide that has been pulled into 



