PrReuGcrURAL AND PHYSIOLOGICAL 
BOTANY. 
INTRODUCTION. 
THE province of Botany, or the Natural History of the | 
Vegetable Kingdom, is to depict the plant from as many 
different points of view as possible. 
| It is impossible to give a brief and exact definition ofa a 
_ plant, if such a definition is intended to include all plants. | 
It is true that from the earliest times the numberless sub- 
stances that are found on the earth have been distinguished 
into living or organic and lifeless or inorganic,—animals and 
_ plants being included in the former, minerals in the latter 
class ; but it is impossible to define accurately the bounds 
of these three kingdoms. Whether a body has life or not 
isa point easily determined, since the presence of life is — 
manifested by various capabilities, the most universally dis- 
tributed of which are those for absorbing and assimilating a_ 
variety of food-materials. We know also from experience that 
the higher and more perfectly organised animals differ from 
the higher plants in possessing sensibility and a power of 
voluntary motion. But when we descend from the higher’ 
B 
