136 SINGLE CENTRES OP CREATION. [Chap. XII. 



difficulty in understanding how the same species could 

 possibly have migrated from some one point to the sev- 

 eral distant and isolated points, where now found. 

 Nevertheless the simplicity of the view that each spe- 

 cies was first produced within a single region captivates 

 the mind. He who rejects it, rejects the vera causa of 

 ordinary generation with subsequent migration, and 

 calls in the agency of a miracle. It is universally ad- 

 mitted, that in most eases the area inhabited by a spe- 

 cies is continuous; and that when a plant or animal 

 inhabits two points so distant from each other, or with 

 an interval of such a nature, that the space could not 

 have been easily passed over by migration, the fact is 

 given as something remarkable and exceptional. The 

 incapacity of migrating across a wide sea is more clear 

 in the case of terrestrial mammals than perhaps with 

 any other organic beings; and, accordingly, we find no 

 inexplicable instances of the same mammals inhabit- 

 ing distant points of the world. No geologist feels any 

 difficulty in Great Britain possessing the same quad- 

 rupeds with the rest of Europe, for they were no doubt 

 once united. But if the same species can be produced 

 at two separate points, why do we not find a single mam- 

 mal common to Europe and Australia or South Amer^ 

 ica? The conditions of life are nearly the same, so that 

 a multitude of European animals and plants have be- 

 come naturalised in America and Australia; and some 

 of the aboriginal plants are identically the same 

 at these distant points of the northern and southern 

 hemispheres? The answer, as I believe, is, that mam- 

 mals have not been able to migrate, whereas some plants, 

 from their varied means of dispersal, have migrated 

 across the wide and broken interspaces. The great 



