480 Mr. A. R. Wallace on the Natural History 



the collector and the systematist contribute so largely. In this 

 point of view the discovery of every new species is important, and 

 their correct description and accurate identification absolutely 

 necessary. The most obscure and minute species are for this 

 purpose of equal value with the largest and most brilliant, and 

 a correct knowledge of the distribution and variations of a beetle 

 or a butterfly as important as those of the eagle or the elephant. 

 It is to the elucidation of these apparent anomalies that the 

 eiforts of the philosophic naturalist are directed ; and we think, 

 that if this highest branch of our science were more frequently 

 alluded to by writers on natural history, its connexion with geo- 

 graphy and geology discussed, and the various interesting pro- 

 blems thence arising explained, the too prevalent idea — that 

 Natural History is at best but an amusement, a trivial and aim- 

 less pursuit, a useless accumulating of barren facts, — would give 

 place to more correct views of a study, which presents problems 

 as vast, as intricate, and as interesting as any to which the 

 human mind can be directed, whose objects are as infinite as the 

 stars of heaven and infinitely diversified, and whose field of re- 

 search extends over the whole earth, not only as it now exists, 

 but also during the countless changes it has undergone from the 

 earliest geological epochs. 



Let us now examine if the theories of modern naturalists will 

 explain the phsenomena of the Aru and New Guinea fauna. 

 We know (with a degree of knowledge approaching to certainty) 

 that at a comparatively recent geological period, not one single 

 species of the present organic world was in existence ; while all 

 the Vertebrata now existing have had their origin still more re- 

 cently. How do we account for the places where they came into 

 existence ? Why are not the same species found in the same 

 climates all over the world ? The general explanation given is, 

 that as the ancient species became extinct, new ones were created 

 in each country or district, adapted to the physical conditions of 

 that district. Sir C. Lyell, who has written more fully, and with 

 more ability, on this subject than most naturalists, adopts this 

 view. He illustrates it by speculating on the vast physical 

 changes that might be effected in North Africa by the upheaval 

 of a chain of mountains in the Sahara. " Then,^^ he says, " the 

 animals and plants of Northern Africa would disappear, and the 

 region w^ould gradually become fitted for the reception of a po- 

 pulation of species perfectly dissimilar in their forms j habits, and 

 organization." Now this theory implies, that we shall find a 

 general similarity in the productions of countries which resemble 

 each other in climate and general aspect, while there shall be a 

 complete dissimilarity between those which arc totally opposed 

 in these respects. And if this is the general law which has 



