| Comparison with 1859 | 
  | 
must originally have proceeded from the same source, as they 
 have | have 1859 1860 1861 1866 |  | are 1869 1872 |  
  
descended from the same progenitor.  In the case of those species, which have undergone during whole geological periods 
 but | but 1859 1860 1861 1866 1869 |  but 1872 |  
  
little modification, there is not much difficulty in believing that they 
 may | may 1859 1860 1861 1866 1869 |  may 1872 |  
  
have migrated from the same region; for during the vast geographical and climatal changes which 
 will | will 1859 1860 1861 1866 |  will 1869 1872 |  
  
have supervened since ancient times, almost any amount of migration is possible.  But in many other cases, in which we have reason to believe 
that the species of a genus have been produced within comparatively recent times, there is great difficulty on this head.  It is also obvious that the individuals of the same species, though now inhabiting distant and isolated regions, must have proceeded from one spot, where their parents were first produced: for, as 
 explained in the last chapter, | explained in the last chapter, 1859 1860 1861 1866 1869 |  
| has been explained, 1872 |  
  
it is incredible that individuals identically the same should 
 ever | ever 1859 1860 |  ever 1861 1866 1869 1872 |  
  
have been produced 
 through natural selection | through natural selection 1859 1860 1861 1866 |  
| OMIT 1869 1872 |  
  
from parents specifically distinct. ↑| Subtitle not present  1859 1860 1861 |  
|  Single  
Centres  
of  
supposed   Creation
.
— 
 1866 1869 1872 |  
  
 | 
 We are thus brought to the question which has been largely discussed by naturalists, namely, whether species have been created at one or more points of the earth's 
surface.  Undoubtedly there are 
 very | very 1859 1860 1861 |  very 1866 1869 1872 |  
  
many cases of extreme 
 difficulty, | difficulty, 1859 1860 |  | difficulty 1861 1866 1869 1872 |  
  
in understanding how the same species could possibly have migrated from some one point to the several distant and isolated points, where now found.  Nevertheless the simplicity of the view that each species 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 admitted, that in most cases the area inhabited by a species is continuous; and 
 when | when 1859 1860 1861 1866 |  | that when 1869 1872 |  
  
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 
 be | be 1859 1860 1861 1866 1869 |  | have been 1872 |  
  
easily passed over by migration, the fact is given as something remarkable and exceptional.  The 
 capacity | capacity 1859 1860 1861 1866 |  | incapacity 1869 1872 |  
  
of migrating across 
 the | the 1859 1860 1861 1866 |  | a wide 1869 1872 |  
  
sea is more 
 distinctly limited in | distinctly limited in 1859 1860 1861 1866 |  
| clear in the case of 1869 1872 |  
  
terrestrial 
 mammals, | mammals, 1859 1860 1861 1866 1869 |  | mammals 1872 |  
  
than perhaps 
 in | in 1859 1860 1861 1866 |  | with 1869 1872 |  
  
any other organic beings; and, 
accordingly, we find no inexplicable 
 cases | cases 1859 1860 1861 1866 |  | instances 1869 1872 |  
  
of the same 
 mammal | mammal 1859 1860 1861 1866 |  | mammals 1869 1872 |  
  
inhabiting distant points of the world.  No geologist 
 will | will 1859 1860 1861 1866 |  will 1869 1872 |  
  
 feel | feel 1859 1860 1861 1866 |  | feels 1869 1872 |  
  
any difficulty in 
 such cases as | such cases as 1859 1860 1861 1866 |  
| OMIT 1869 1872 |  
  
Great Britain 
 having been formerly united to Europe, and consequently | having been formerly united to Europe, and consequently 1859 1860 1861 1866 |  
| OMIT 1869 1872 |  
  
possessing the same 
 quadrupeds. | quadrupeds. 1859 1860 1861 1866 |  
| quadrupeds with the rest of Europe, for they were no doubt once united. 1869 1872 |  
   But if the same species can be produced at two separate points, why do we not find a single mammal common to Europe and Australia 
or South America?  The conditions of life are nearly the same, so that a multitude of European animals and plants have become 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 
 | 
 
  
  
must originally have proceeded from the same source, as they 
 are | are 1869 1872 |  | have 1859 1860 1861 1866 |  
  
descended from the same progenitor.  In the case of those species, which have undergone during whole geological periods 
 ..| ..... 1872 |  | but 1859 1860 1861 1866 1869 |  
  
little modification, there is not much difficulty in believing that they 
 ..| ..... 1872 |  | may 1859 1860 1861 1866 1869 |  
  
have migrated from the same region; for during the vast geographical and climatal changes which 
 ..| ..... 1869 1872 |  | will 1859 1860 1861 1866 |  
  
have supervened since ancient times, almost any amount of migration is possible.  But in many other cases, in which we have reason to 
 believe | believe 1859 1860 1861 1866 1872 |  | believ 1869 |  
  
that the species of a genus have been produced within comparatively recent times, there is great difficulty on this head.  It is also obvious that the individuals of the same species, though now inhabiting distant and isolated regions, must have proceeded from one spot, where their parents were first produced: for, as 
 has been explained, | has been explained, 1872 |  
| explained in the last chapter, 1859 1860 1861 1866 1869 |  
  
it is incredible that individuals identically the same should 
 ..| ..... 1861 1866 1869 1872 |  | ever 1859 1860 |  
  
have been produced 
 ...| OMIT 1869 1872 |  
| through natural selection 1859 1860 1861 1866 |  
  
from parents specifically distinct.  | 
 
Single
 | 
Single
 1866 1872 |  | 
Single
 1869 |  
  
 
Centres
 | 
Centres
 1866 1872 |  | 
Centres
 1869 |  
  
 
of
 
 
Supposed
 | 
Supposed
 1872 |  | 
supposed
 1866 |  | 
supposed
 1869 |  
  
 
Creation
.—
 | 
Creation
.—
 1866 1872 |  
| 
Creation
.
—
 1869 |  
  
 | 
 We are thus brought to the question which has been largely discussed by naturalists, namely, whether species have been created at one or more points of the 
 earth's | earth's 1859 1860 1861 1866 1872 |  | earths 1869 |  
  
surface.  Undoubtedly there are 
 ..| ..... 1866 1869 1872 |  | very 1859 1860 1861 |  
  
many cases of extreme 
 difficulty | difficulty 1861 1866 1869 1872 |  | difficulty, 1859 1860 |  
  
in understanding how the same species could possibly have migrated from some one point to the several distant and isolated points, where now found.  Nevertheless the simplicity of the view that each species was first produced within a single region captivates the mind.  He who rejects it, rejects the 
 
vera
 | 
vera
 1859 1860 1866 1869 1872 |  | vera 1861 |  
  
 
causa
 | 
causa
 1859 1860 1866 1869 1872 |  | causa 1861 |  
  
of ordinary generation with subsequent migration, and calls in the agency of a miracle.  It is universally admitted, that in most cases the area inhabited by a species is continuous; and 
 that when | that when 1869 1872 |  | when 1859 1860 1861 1866 |  
  
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 | have been 1872 |  | be 1859 1860 1861 1866 1869 |  
  
easily passed over by migration, the fact is given as something remarkable and exceptional.  The 
 incapacity | incapacity 1869 1872 |  | capacity 1859 1860 1861 1866 |  
  
of migrating across 
 a wide | a wide 1869 1872 |  | the 1859 1860 1861 1866 |  
  
sea is more 
 clear in the case of | clear in the case of 1869 1872 |  
| distinctly limited in 1859 1860 1861 1866 |  
  
terrestrial 
 mammals | mammals 1872 |  | mammals, 1859 1860 1861 1866 1869 |  
  
than perhaps 
 with | with 1869 1872 |  | in 1859 1860 1861 1866 |  
  
any other organic beings; 
 and, | and, 1859 1860 1861 1866 1872 |  | and 1869 |  
  
accordingly, we find no inexplicable 
 instances | instances 1869 1872 |  | cases 1859 1860 1861 1866 |  
  
of the same 
 mammals | mammals 1869 1872 |  | mammal 1859 1860 1861 1866 |  
  
inhabiting distant points of the world.  No geologist 
 ..| ..... 1869 1872 |  | will 1859 1860 1861 1866 |  
  
 feels | feels 1869 1872 |  | feel 1859 1860 1861 1866 |  
  
any difficulty in 
 ...| OMIT 1869 1872 |  
| such cases as 1859 1860 1861 1866 |  
  
Great Britain 
 ...| OMIT 1869 1872 |  
| having been formerly united to Europe, and consequently 1859 1860 1861 1866 |  
  
possessing the same 
 quadrupeds with the rest of Europe, for they were no doubt once united. | quadrupeds with the rest of Europe, for they were no doubt once united. 1869 1872 |  
| quadrupeds. 1859 1860 1861 1866 |  
   But if the same species can be produced at two separate points, why do we not find a single mammal common to Europe and 
 Australia | Australia 1859 1861 1866 1869 1872 |  | Aus- tralia 1860 |  
  
or South America?  The conditions of life are nearly the same, so that a multitude of European animals and plants have become 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 
 |