be expressed by groups subordinate to groups; but the proper or even 
 only | only 1859 1860 1861 1866 1869 |  | the only 1872 |  
  
possible arrangement would still be genealogical; and this would be strictly natural, as it would connect together all languages, extinct and 
 modern, | modern, 1859 1860 1861 1866 |  | recent, 1869 1872 |  
  
by the closest affinities, and would give the filiation and origin of each tongue.  | 
 In confirmation of this view, let us glance at the classification of varieties, which are 
 believed | believed 1859 1860 1861 1866 1869 |  | known 1872 |  
  
or 
 known | known 1859 1860 1861 1866 1869 |  | believed 1872 |  
  
to 
 have | have 1859 1860 1861 1866 |  | be 1869 1872 |  
  
descended from 
 one | one 1859 1860 1861 1866 |  | a single 1869 1872 |  
  
species.  These are grouped under 
 species, with | species, with 1859 1860 1861 1866 |  
| the species, with the 1869 1872 |  
  
sub-varieties under 
 varieties; and with our domestic productions, | varieties; and with our domestic productions, 1859 1860 1861 1866 |  
| the varieties; and in some cases, as with domestic pigeons, 1869 |  
| the varieties; and in some cases, as with the domestic pigeon, with 1872 |  
  
several other grades of 
 difference | difference 1859 1860 1861 1866 1869 |  | difference. 1872 |  
  
 are | are 1859 1860 1861 1866 1869 |  are 1872 |  
  
 requisite, | requisite, 1859 1860 1861 1866 |  | requisite. 1869 |  requisite, 1872 |  
  
 as | as 1859 1860 1861 1866 |  as 1872 |  as 1869 |  
  
 we | we 1859 1860 1861 1866 |  we 1872 |  we 1869 |  
  
 have | have 1859 1860 1861 1866 |  have 1872 |  have 1869 |  
  
 seen | seen 1859 1860 1861 1866 |  seen 1872 |  seen 1869 |  
  
 with | with 1859 1860 1861 1866 |  with 1872 |  with 1869 |  
  
 pigeons. | pigeons. 1859 1860 1861 1866 |  pigeons. 1872 |  pigeons. 1869 |  
   The origin of the existence of groups subordinate to 
 groups | groups 1861 1866 |  | groups, 1859 1860 |  
  
is the same with varieties as with species, namely, closeness of descent with various degrees of modification.  Nearly the same rules are followed 
 in classifying varieties, as with | in classifying varieties, as with 1859 1860 1861 1866 |  
| as in classifying 1869 1872 |  
  
species.  Authors have insisted on the necessity of 
 classing | classing 1859 1860 1861 1866 |  | arranging 1869 1872 |  
  
varieties on a natural instead of an artificial system; we are cautioned, for instance, not to class two varieties of the pine-apple together, merely because their fruit, though the most important part, happens to be nearly identical; no one puts the 
 Swedish | Swedish 1861 1866 1869 1872 |  | swedish 1859 1860 |  
  
and common 
 turnips | turnips 1859 1860 1861 1866 1869 |  | turnip 1872 |  
  
together, though the esculent and thickened stems are so similar.  Whatever part is found to be most constant, is used in classing varieties: thus the great agriculturist Marshall says the horns are very useful for this purpose with cattle, because they are less variable than the shape or colour of the body, &c.; whereas with sheep the horns are much less serviceable, because less constant.  In classing 
 varieties, | varieties, 1859 1860 1861 1866 1869 |  | varieties; 1872 |  
  
I apprehend 
 if | if 1859 1860 1861 |  | that if 1866 1869 1872 |  
  
we had a real pedigree, a genealogical classification would be universally 
 preferred; | preferred; 1859 1860 1861 1866 1872 |  | preferred: 1869 |  
  
and it has been attempted 
 by | by 1859 1860 1861 1866 |  | in 1869 1872 |  
  
some 
 authors. | authors. 1859 1860 1861 1866 |  | cases. 1869 1872 |  
   For we might feel sure, whether there had been more or less modification, 
 the | the 1859 1860 1861 1866 1869 |  | that the 1872 |  
  
principle of inheritance would 
 |