134 MISSOURI STATE HORTICULTURAL SOCIEIY. 



consist of the cell wall or membrane and its contents. The cell wall is 

 a thin partition of dead matter called cellulose. This cellulose has the 

 same constitution, as starch, oxygen, carbon and hydroiien. It is 

 white, tough, elastic and fibrous. You can see it in the skeleton of the 

 leaves, so often visible on trees where all the cells have been eaten off. 



It is the frame work of all plants. In the first stages of life the 

 cell consists entirely of cellulose, but as plants grow the walls become 

 encrusted with resins and coloring matter. This forms the food of 

 herbivorous animals. This cell wall contains, while young, this viscid 

 flaid, like itself, protoplasm. As plants grow, or rather as this pro- 

 toplasm divides, plants do grow, and we see the elongation of the 

 roots, branches and leaves. When the woody matter forms, the fluid 

 evaporates and leaves a cavity filled with air. This is seen plainly in 

 the bark of trees, the pith and in the old wood. 



This protoplasm clings to the cell walls as the cells grow, so as to 

 line it, and the interior of this space is filled with cell sap. This proto- 

 plasm still later forms a thin film, and a nucleus is formed and strings 

 of protoplasm form across the cell cavity from this nucleus. This in 

 young cells divides into halves, a wall of cellulose forms, and thus new 

 cells are formed. These take place so rapidly as to be almost without 

 number. These cells are only about 1-300 to I-IOOO of an inch, so that 

 a cubic inch contains from 25,000,000 to 100,000,000 of cells. Thus, 

 when you see a plant growing one or two inches per day you can 

 imagine the immense number of these divisions and cell formations 

 per day. 



Prof. Gray states in his botany that a century plant throwing up 

 its flower stalk, six laches per day, formed every day twenty thousand 

 million cells, a number beyond our comprehension. 



In the green parts of plants the protoplasm undergoes a change, 

 by which a part of it is broken up into granules, which contain a green 

 coloring matter called chlorophyl, and these granules are very numer- 

 ous in the surface cell of plants, and the color of the leaves seen through 

 the thin cell walls. tSimilar granules, but of difterent colors, are seen 

 in the flowers. What forms this color out of water and soil is a query. 



This chlorophyl under the action of the sunlight separates the car- 

 bonic acid of the air and gives out oxygen to the air and carbon to the 

 plant. 



Starch is formed by the carbon combining the oxygen and hydrogen 

 of water. This chlorophyl is only farmed by sunlight, for if it is with- 

 drawn the blanching process appears. 



The plant seems to have the power to change the starch, mucilage, 

 sugar and plant fabric, one into the other as it may need. So that one 



