INTRODUCTION 



BEFORE we begin to study plants in any way, we may, with 

 profit, consider what sort of things are to be the objects to 

 which our attention will be given. In taking a general sur- 

 vey of the objects we know in nature, and inquiring as to 

 how we separate the plants from the rest, we consider, 

 roughly at least, the following subjects : 



1. Life. We readily separate, as far as most things are 

 concerned, the members of the mineral kingdom from those 

 which belong to the animal and vegetable kingdoms, distin- 

 guishing the two latter from the former by the fact that they 

 are living. We need not undertake to investigate the nature 

 of life, i.e. what life really is ; we may be content with con- 

 sidering it as a certain kind of force which manifests itself in 

 certain ways through matter, and that upon the cessation of 

 this force what we call death ensues. 



2. Plant and Animal Life. We distinguish, popularly, 

 animal life from plant life in that the animal life is animated 

 while the plant life is not. The ordinary animals exhibit 

 various movements which they can control, they eat, etc., 

 and we do not question their living activities ; but the 

 plants, with few exceptions, do not appeal to us as being 



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