166 PLANT-LIFE. [LESSON 27. 



form of nitrate of ammonia) out of the nitrogen of the air and the 

 vapor of water. The reason why it never accumulates in the air 

 so as to be perceptible is, that it is extremely soluble in water, as 

 are all its compounds. So it is washed out of the atmosphere by the 

 rain as fast as it is made or rises into it, and is brought down to the 

 roots of plants, which take it in freely. When assimilated in the 

 leaves along with carbon and water, proteine is formed, the very 

 substance of the flesh of animals. So all iiesh is vegetable matter 

 in its origin. 



477. Even the earthy matter of the bones, and the iron and other 

 mineral matters in the blood of animals, are derived from the plants 

 they feed upon, with hardly an exception. These are furnished by 

 the earthy or mineral constituents of plants (452), and are mereljf 

 accumulated in the animal frame. 



478. Animals, therefore, depend absolutely upon vegetables for 

 their being. The great object for which the All-wise Creator estab- 

 lished the vegetable kingdom evidently is, that plants mi^ht stand on 

 the surface of the earth between the mineral and the animal crea- 

 tions, and organize portions of the former for the sustenance of 

 the latter. 



LESSON XXVII. 



PLANT-LIFE. 



479. LIFE is known to us only by its effects. We cannot tell 

 what it is : but we notice some things which it does. One peculi- 

 arity of living things, which has been illustrated in the last Lesson, 

 is their power of transforming matter into new forms, and thereby 

 making products never produced in any other way. Life is also 

 manifested by 



480. Motion, that is, by self-caused movements. Living things 

 move ; those not living are moved. Animals, living as they do 

 upon organized food, which is not found everywhere, must 

 needs have the power of going after it, of collecting it, or at least of 

 taking it in ; which requires them to make spontaneous movements. 

 But plants, with their wide-spread surface (34, 13H always in con- 



