54 MODE OF ARRANGING SPECIES NATURALLY. 



to place. He still goes on, however, introducing the former in 

 the best way he can, among those to which they have an evident 

 affinity, and placing the lattei by themselves, in the hope of 

 finally discovering their proper place. The further he proceeds, 

 however, these difficulties are rather increased than diminished. 

 He remodels his groups, and alters his series ; still he cannot 

 reduce all into harmonious order. What he gains by one modi- 

 fication of arrangement, he loses in another ; and affinities which 

 were preserved in his first series, are destroyed, that a place may 

 be found for other insects, which seem to have equally strong 

 relations, although in some respects they evidently disturb the 

 order of progression. 



34. " But his difficulties do not terminate here ; for, admit- 

 ting the possibility of his success in bringing every species into 

 an appropriate group, the union of these groups among them- 

 selves opens a new source of embarrassment. It is plain that, in 

 the order of nature, they must follow one another in some sort ; 

 for, if there were no progression of development, all animals 

 would be equally perfect that is to say, would have the same 

 complexity of structure. Here, then, lies his difficulty. He 

 perceives, perhaps, an evident affinity between two groups, by 

 species which seem to blend them together, and to conduct him, 

 by an almost insensible gradation, from one to the other. He 

 therefore concludes this to be the natural series, and he approxi- 

 mates them accordingly. Presently, however, upon looking more 

 attentively to his other unsorted groups, he finds not only one, 

 but several, each of which, in some way or other, shows an 

 approximation just as close to his first group, as that does which 

 he had previously made to follow it ; and he is as much at a loss 

 how to dispose his groups in natural succession, as he was how to 

 place the species they contain. The same results also attend his 

 attempts at improving his arrangement of groups ; what is gained 

 by shifting one so as to follow another, is lost by dissevering it 

 from that with which it was previously united : until, with all 

 his assiduity and trials, he finds, that there is still a remnant of 

 * unknown things," 1 which stand disconnected, as it were, from the 



