266 Mr. Bicheno on Systems and Methods 



such striking modifications of form as we discover in the genus 

 Erica, Rosa, Eriocaidon, &c, among plants, and in Vesper- 

 tilio, Strix, Scarabaeus, &c, among animals, it would be the 

 height of folly to give up a term so expressive and at the same 

 time so useful, or to transfer its received meaning to some 

 other word which has not been used in the same sense. 



As the success of the systematist depends so materially upon 

 the proper use of these abstractions, I shall now proceed to 

 show some distinctions which it is necessary to keep in view 

 while we employ them. We aim, as I said before, at two di- 

 stinct objects by the use of systems : we use the artificial for 

 becoming acquainted with individuals, and the natural as the 

 means of combining them, and enabling the student to com- 

 prehend and speak of the general truths relating to nature by 

 a knowledge of a few particulars. 



Division and separation is the end of the artificial system : — 

 to establish agreements is the end of the natural. In one case 

 we reason a priori; in the other a posteriori. The one is a 

 descending, the other an ascending series. Linnaeus under- 

 stood this distinction when he remarked, " Ordines naturales 

 valent de natura plantarum; artificiales in diagnosi planta- 

 rum." — " Cavendo in imitando naturam filum Ariadneum 

 amittamus." Nevertheless it has appeared to me that many 

 modern naturalists have not adopted these truths ; and that it 

 is the prevalent error of the day to attempt to generalize where 

 they ought to analyse; while their arrangements, called na- 

 tural, are almost all of them framed with a view to distinguish. 

 Let me not be supposed by these remarks to wish to exclude 

 from the natural system every attempt at diagnosis ; for it is 

 obvious, that as the business of the naturalist is to study all 

 the characters, he can no more neglect differences than he can 

 agreements. I only wish to point out the two dissimilar ob- 

 jects we have in view, that they may not be confounded. 



M. Decandolle, for instance, whose labours as a systematist 

 are invaluable, seems to overlook this distinction. In his 

 Regni Vegetabilis Sy sterna Naturale, he starts from things the 

 least known, to reason on things best known. He begins 

 his comprehensive work with a predicate of the stars; and, 

 proceeding downwards to minerals, comes to plants. Here 

 he employs a series of terms expressive of a natural gradation 

 from the highest to the lowest group, attempting fresh com- 

 binations at every stage, and making a place for every thing. 

 Thus he has class, sub- class, cohort, order, tribe, genus, section, 

 species. The extraordinary number of these combinations di- 

 minishes their value as a work of natural arrangement. It is 

 a difficulty of sufficient amount to establish a few well marked ; 



and 



