22 On the present state of Zoology. 
serve to elucidate all the laws by which the exact plan of nature is 
regulated. 
We would here briefly remind those who enter upon the investiga- 
tion of the natural affinities of animals, of the importance of being 
guided by certain acknowledged principles, quite independent of 
those general laws above alluded to, indeed independent of all theory 
whatever, and equally deserving our regard, whether we incline to any 
theory or not. They respect the value of organs and the subordina- 
tion of characters. Except we set out in our enquiries with some 
definite ideas on these points, we shall be perpetually falling into er- 
ror. In order to discover the true affinities of animals, it is not suf- 
ficient that we compare their respective characters, and then note 
what marks of resemblance are to be traced between them : we must 
first ascertain what is the relative value of the different organs, which 
furnish those characters. And how is this to be determined? By 
observing which organs exercise the most important functions, or are 
of most general occurrence. It will be found on such an enquiry, 
that some appear to take the lead of others, that while some are 
constantly present, others are often wanting, and that even among 
the former, we may trace, in different instances, very different degrees 
of variation. Now by paying regard to these circumstances, we es- 
tablish gradually that subordination of characters, to which we have 
before alluded as first employed in this science by Cuvier, and which 
must be the basis of all natural classification. Our limits will not 
allow us to enter at any length upon this subject, or we might advert 
to certain rules, founded partly upon observed facts partly upon 
common principles of reasoning, which have been drawn up with re- 
ference to these enquiries, and which ought to be well studied by the 
Zoologist. * We regret, indeed, that, in some instances, they have 
not been more attended to. Had it been otherwise, we should not 
see so many conflicting opinions respecting classification ; we should 
not see groups of very unequal value placed exactly upon the same 
footing, genera founded upon the most trivial distinctions, and such 
* Many of these rules apply equally well, or with some slight modification 
may be made applicable, to the two sciences of Zoology and Botany. On these 
grounds, we strongly recommend to the attention of naturalists some portions of 
the Theorie elementaire de la Botanique of M. Decandolle, where they are laid 
down with more clearness and precision than in any zoological work with which 
we are acquainted. The student, however, may consult with advantage the 
seventh part of Lamarck's Introduction to his Hist. Nat. des. An. sans Vertebres, 
divesting it of those peculiar theoretical views which pervade the whole of that 
volume. 
