14 INTRODUCTION. 



the kind of life with which it is endowed, the organization through 

 which its life is manifested ; in other words, how the plant lives 

 and grows, and fulfils its destined officest This is the province of 

 PHYSIOLOGICAL BOTANY. It comprises a knowledge, 1st, 

 of the intimate structure of the plant, the minute machinery 

 through which its forces operate ; this is the special field of 

 VEGETABLE ANATOMY; and, 2d, of the plant's external con- 

 formation, the forms and arrangement of the several organs of 

 which it is composed, the laws of symmetry which fix their posi- 

 tion, and the modifications they respectively undergo, whether in 

 different species, under different conditions, or in a single individ- 

 ual during the successive stages of its development. This branch 

 of the science is variously called ORGANOGRAPHY (the study of the 

 organs), or MORPHOLOGY (the study of their various modifications 

 in form, according to the office they are destined to subserve), or 

 STRUCTURAL BOTANY ; and nearly corresponds with what is termed 

 Comparative Anatomy in the animal kingdom. Under both these 

 aspects, (whether we study their interior structure, or their external 

 conformation,} the plant is viewed as a piece of machinery, adapt- 

 ed to effect certain ends. The study of this apparatus in action, 

 endowed with life, and fulfilling the purposes for which it was 

 constructed, is the province of VEGETABLE PHYSIOLOGY, strictly so 

 called. 



4. The subjects which Physiological Botany embraces, namely, 

 Vegetable Anatomy, Organography, and Physiology, therefore, 

 spring naturally from the study of vegetables as individuals, 

 from the contemplation of an isolated plant throughout the course 

 of its existence, from germination to the flowering state, and the 

 production of a seed like that from which the parent stock origi- 

 nated. These branches would equally exist, and would form a 

 highly interesting study, (analogous to human anatomy and physi- 

 ology,) even if the vegetable kingdom were restricted to a single 

 species. 



5. But the science assumes an immeasurably broader interest 

 and more diversified attractions, when we look upon the vegetable 

 creation as consisting, not of wearisome repetitions of one particu- 

 lar form, in itself however perfect or beautiful, but as composed of 

 thousands of species, all constructed upon one general plan, in- 

 deed, but this plan modified in each according to the rank it holds, 

 and the circumstances in which it is placed. This leads to the 



