INTRODUCTION. 



WE now arrive at that study which offers the most copious 

 and complete example of the sciences of classification, I mean 

 Botany. And in this case, we have before us a branch of knowledge 

 of which we may say, more properly than of any of the sciences 

 which we have reviewed since Astronomy, that it has been constantly 

 advancing, more or less rapidly, from the infancy of the human race 

 to the present day. One of the reasons of this resemblance in the 

 fortunes of two studies so widely dissimilar, is to be found in a simpli- 

 city of principle which they have in common ; the ideas of Likeness 

 and Difference, on which the knowledge of plants depends, are, like 

 the ideas of Space and Time, which are the foundation of astronomy, 

 readily apprehended with clearness and precision, even without any 

 peculiar culture of the intellect. But another reason why, in the his- 

 tory of Botany, as in that of Astronomy, the progress of knowledge 

 forms an unbroken line from the earliest times, is precisely the great 

 difference of the kind of knowledge which has been attained in the 

 two cases. In Astronomy, the discovery of general truths began at an 

 early period of civilization ; in Botany, it has hardly yet begun ; and 

 thus, in each of these departments of study, the lore of the ancient 

 is homogeneous with that of the modern times, though in the one 

 case it is science, in the other, the absence of science, which pervades 

 all ages. The resemblance of the form of their history arises from 

 the diversity of their materials. 



I shall not here dwell further upon this subject, but proceed to 

 trace rapidly the progress of Systematic Botany, as the classificatory 

 science is usually denominated, when it is requisite to distinguish 

 between that and Physiological Botany. My own imperfect acquaint- 

 ance with this study admonishes rne not to venture into its details, 

 further than my purpose absolutely requires. I trust that, by taking 

 my views principally from writers who are generally allowed to pos- 

 sess the best insight into the science, I may be able to draw the 

 larger features of its history with tolerable correctness ; and if I suc- 

 ceed in this, I shall attain an object of great importance in my general 

 scheme. 



