PREFACE. Vli 



The principles of such a science must necessarily be 

 complicated, and in certain branches, which have only 

 for a short time occupied the attention of observers, or 

 which depend upon obscure and ill-understood evidence, 

 are less clearly denned than could be wished. To 

 explain those principles ; to adduce the evidence by 

 which their truth is supposed to be proved, or the 

 reasoning upon which they are based in cases where 

 direct proof is unattainable ; to show the causes of 

 errors now exploded, the insufficiency of the arguments 

 by which doubtful theories are still defended, and, in 

 fine, to draw a line between what is certain and what is 

 doubtful, are some of the objects of this publication, 

 which is intended for the use of those who, without 

 being willing to occupy themselves with a detailed 

 examination of the vast mass of evidence upon which 

 the modern science of botany is founded, are, neverthe- 

 less, anxious to acquire a distinct idea of the nature of 

 that evidence. Another and not less important purpose 

 has been to demonstrate, by a series of well-connected 

 proofs, that in no department of natural history are the 

 simplicity and harmony that pervade the universe more 

 strikingly manifest that in the vegetable kingdom, where 

 the most varied forms are produced by the combination 

 of a very small number of distinct organs, and the most 

 important phenomena are distinctly explained by a few 

 simple laws of life and structure. 



In the execution of these objects, I have followed 

 very nearly the method recommended by the celebrated 

 Professor De Candolle, than whom no man is entitled 

 to more deference, whether you consider the soundness 

 of his judgment in all that relates to order and arrange- 



