BOOK iit 
PHYSIOLOGY OF PLANTS, OR PHYSIOLOGICAL 
BOTANY. 
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Havine now examined the structure, classification, properties 
and uses of plants, we have still to consider them in a state of 
life or action, and to explain, as far as science enables us, the 
laws which regulate their life, growth, and reproduction. The 
department of Botany which investigates these phenomena is 
termed Physiology ; and the various processes which go on in 
the plant, and which are the necessary accompaniments of its 
life, are called its functions. The different vital actions are 
naturally divided into classes, called, respectively, the functions 
of the organs of nutrition, and the functions of the organs of” 
reproduction ; the former being those concerned in preserving 
the life of the particular plant, and the latter in continuing the 
species. Physiology includes the study of the life of the 
whole plant, when it is termed general, and that of the particu- 
lar organs, in which case it is called special ; and each division 
may be further divided into Physiological Chemistry, and Phy- 
siological Physics. 
The present state of our knowledge of many points connected 
with the physiology of plants is so imperfect that there is some 
difficulty in arranging a good plan for its study. In examining, 
therefore, the functions of the different organs, the order of 
arrangement adopted in treating of their structure and morpho- 
logy will be followed as far as possible, after which will be added 
a brief notice of General Physiology, and some observations on 
Special Phenomena in the life of the whole plant. 
AZ. . 
