1 2 INTRODUCTION. [11, 12. 



stone, for example, may be broken into any number 

 of fragments, each of which will retain all the essen- 

 tial characteristics of the original body, so that each 

 fragment will still be a stone. 



14. A plant is an organized body, endowed with 

 vitality but not with sensation, composed of distinct 

 parts, each of which is essential to the completeness 

 of its being. A Tulip is composed of organs which 

 may be separated and subdivided indefinitely, but no 

 one of the fragments alone will be a complete plant. 



15. Animals, like plants, are organized bodies en- 

 dowed with vitality, and composed of distinct parts, 

 no one of which is complete in itself ; but they are 

 elevated above either plants or minerals by their 

 power of perception. 



16. Physics is the general name of the science 

 which treats of the mineral or inorganic world. 



17. Zoology relates to the animal kingdom. 



18. Botany is the science of the vegetable king- 

 dom. It includes the knowledge of the forms, organs, 

 structure, growth, and uses of plants, together with 

 their history and classification. Its several depart- 

 ments correspond to the various subjects to which 

 they relate. Thus, 



19. Morphology treats of the special organs of plants 

 as compared with each other ; it especially relates to 

 the mutual or typical transformations which the 

 organs undergo in the course of development. 



20. Vegetable Histology treats of the elementary 

 tissues the organic units or cells out of which the 

 vegetable fabric is constructed. 



21. Physiological Botany is that department which 

 relates to the vital action of the several organs and 



