12 INTRODUCTION. 



just as we might wish to do in our laboratories; showing us, herself, 

 at the same time their various results. 



In this way we finally succeed in establishing certain laws by which 

 these relations are governed, and which are employed like those 

 that are determined by the general sciences. 



The incorporation of these laws of observation with the general 

 laws, either directly or by the principle of the conditions of exist- 

 ence, would complete the system of the natural sciences, in render- 

 ing sensible in all its parts the mutual influence of every being. To 

 this end, should those who cultivate these sciences direct all their 

 eflfbrts. 



All researches of this nature, however, pre-suppose means of dis- 

 tinguishing clearly, and causing others to distinguish, the bodies they 

 are occupied with; otherwise we should be continually confounding 

 them. Natural History then should be based on what is called a 

 System of Nature; or a great catalogue, in which all created beings 

 have suitable names, may be recognised by distinctive characters, 

 and be arranged in divisions and subdivisions, themselves named and 

 characterised, in which they may be found. 



In order that each being may be recognised in this catalogue, it 

 must be accompanied by its character: habits or properties which 

 are but momentary cannot, then, furnish characters — they must be 

 drawn from the conformation. 



There is scarcely a single being which has a simple character, 

 or can be recognised by one single feature of its conformation; a 

 union of several of these traits are almost always required to dis- 

 tinguish one being from those that surround it, who also have some 

 but not all of them, or who have them combined with others of 

 which the first is destitute. The more numerous the beings to be 

 distinguished, the greater should be the number of traits; so that to 

 distinguish an individual being from all others, a complete descrip- 

 tion of it should enter into its character. 



It is to avoid this inconvenience, that divisions and subdivisions 

 have been invented. A certain number only of neighbouring beings 

 are compared with each other, and their characters need only to 

 express their difl^erences, which, by the supposition itself, are the 

 least part of their conformation. Such a re-union is termed a genus. 



The same inconvenience would be experienced in distinguishing 

 genera from each other, were it not for the repetition of the opera- 

 tion in uniting the adjoining genera, so as to form an order., the 



