VEGETATION, OK THE PHYSIOLOGY OF PLANT LIFE. 147 



740. THE SUBORDINATION OF THE VEGETABLE to the animal kingdom 

 is thus manifest in its being fed and nourished on inorganic matter. It 

 is interposed between these two incompatible extremes, and is ordained 

 to transform the innutritions mineral into the proper and indispensable 

 food of the animal kingdom. 



741. PARASITIC PLANTS do indeed require the ready organized juices of other 

 plants, just as the earnivora among animals live on flesh. Still the general fact re- 

 mains, that plants alone feed on inorganic matter, and in turn become themselves 

 the food of the animal kingdom. 



742. THE PROCESS OF VEGETATTON consists of imbibing the crude 

 matters of the earth and air, transforming into sap, assimilating to 

 plant juice (latex), and organizing into its own structure according to 

 its own plan. The vital phenomena on which these transformations de- 

 pend are called absorption, circulation, exhalation, assimilation, secretion, 

 all of which processes take place in the individual cell. Therefore, 



743. CELL-LIFE is an epitome of the life of the whole plant. The cell is never a 

 spontaneous production ; it is the offspring of a pre-existing cell. So with the 

 plant ; it is always the offspring of a pre-existing embryo or celL Nothing but a 

 cell can produce or nourish a celL 



744. Two KINDS OF ORGANIC MATTER make up the cell. The first 

 protoplasm or protein (C^ H 31 O 12 N 5 ), the material of the primordial 

 utricle ( 645), etc., containing nitrogen; 2d, cellulose, (C^ H 10 ON,), the 

 material of the outer wall or crust, etc., containing no nitrogen. The 

 former more nearly resembles animal matter, and is the seat of the vital 

 force and chemical action. 



745. WHAT THE CELL m- 



BIBES. Through the invisible ^ @ 



pores of its walls the cell imbibes ^oS/ .^ 



the fluid in which its food is dis- ^ (J> * x 



solved, viz., sugar or dextrine, v^ |5| 



ammonia or some other nitrogen- ^ p rotococcMViridi8>the 



OUS substance. Such a fluid may Green snow-plant. cum, the Yeast-plant. 



be the flowing sap of the plant or any similar artificial mixture in which 

 the cell is bathed, as (in the case of the yeast plant) a syrup with mu- 

 cilage. 



746. THE CHEMICAL CHANGES. The sugar is thus brought into con- 

 tact with the protoplasm in the cell, through whose action it is decom- 

 posed and its elements transformed into cellulose and water. Thus 

 each atom of (grape) sugar or dextrine becomes 



One atom of cellulose, C ]9 H 10 0, 

 and two atoms of water, H 2 O s 



CH H, 2 Ou=grape sugar. 



