On the -present state of Zoology. 9] 



principles : It is undoubtedly allowable, without waiting for the ac- 

 quirement of all possible facts that can be obtained, to try any theory 

 which explains those already in our possession, by applying it to 

 such as may be observed afterwards. But the danger is, in the science 

 now before us, especially when we have to deal with analogical rela- 

 tions, that we mistake for facts — points, which may certainly appear 

 as such to us, but which are of that nature that they must infallibly 

 strike different observers in different lights according to the impres- 

 sions upon the mind at the time of viewing them. Hence it is that 

 we conceive, that we are more likely to see these relations truly, when 

 we have no theory to support ; — when there is nothing which is like- 

 ly to warp our judgment. We believe that if we made it our first en- 

 deavour to arrange all animals according to their best ascertained af- 

 finities, at the same time noting any other less obvious relation ; and 

 if we then drew lines of separation between such groups as appeared 

 well characterized, taking care to assign to each a rank proportioned 

 to its true value ; we should gradually arrive in this manner at as 

 just a conception of the true order of nature as, perhaps, it is possible 

 to attain. * For, after all, it becomes a question, whether, assuming 

 that there is some definite plan in nature grounded upon fixed prin- 

 ciples, we can ever hope to understand more than part of it. When 

 we consider how much is requisite to complete the history of a single 

 species, and that we need to be acquainted with this history, not only 

 in the case of all existing animals, but of all lost ones also, — we may 

 conceive how vast must be the task of tracing the relations which one 

 species bears to the others. We can scarcely do more than make some 

 approximation to the truth. — We can only arrange our groups in such 

 a manner, that there be no other known ones more nearly allied to 

 be brought in between those which stand next each other. And the 

 system which does this may be called natural, f although it may not 



* The above will be found nearly in accordance with Lamarck's judicious ob- 

 servation on this subject, which it may be well to repeat here. He says, — 

 " Nous avons senti que, pour reussir a etablir nne bonne distribution des animaux, 

 sans que l'arbitraire de l'opinion en affaiblisse nulle part la solidite, il etait ne- 

 cessaire, avant tout, de rapprocher les animaux les uns des autres, d'apres leurs 

 rapports les mieux determines ; et qu' ensuite, l'on pourrait, sans inconvenient, 

 tracer les lignes de separation qui detachent les masses classiques, ainsi que les 

 coupes subordonnees, utiles a etablir, pourvu que les rapports ne fussent nulle 

 part compromis par la composition et l'ordre de nos diverses coupes." — Hist. 

 Nat. des An. sans Vert. (2d edit.) tome i. p. 285. 



f This remark is Cuvier's • but we are unable to refer to the exact place in 

 which it is expressed. 



