CLASSIFICATION 381 



degrees of modification. Nearly the same rules are 

 followed in classifying 1 varieties, as with species. Author? 

 have insisted on the necessity of classing varieties on a 

 natural instead of an artificial system ; we are cau- 

 tioned, 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 and common turnips 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, etc. ; whereas with sheep 

 the horns are much less serviceable, because less 

 constant. In classing varieties, I apprehend if we had 

 a real pedigree, a genealogical classification would be 

 universally preferred ; and it has been attempted by 

 some authors. For we might feel sure, whether there 

 had been more or less modification, the principle of 

 inheritance would keep the forms together which were 

 allied in the greatest number of points. In tumbler 

 pigeons, though some sub-varieties differ from the others 

 in the important character of having a longer beak, yet 

 all are kept together from having the common habit 

 of tumbling ; but the short-faced breed has nearly or 

 quite lost this habit ; nevertheless, without any reasoning 

 or thinking on the subject, these tumblers are kept in 

 the same group, because allied in blood and alike in 

 some other respects. If it could be proved that the 

 Hottentot had descended from the Negro, I think he 

 would be classed under the NegTo group, however much 

 he might differ in colour and other important character* 

 from negroes. 



With species in a state of nature, every naturalist has 

 in feet brought descent into his classification ; for he 

 includes in his lowest grade, or that of a species, the 

 two sexes ; and how enormously these sometimes differ 

 in the most important characters, is known to every 

 naturalist : scarcely a single fact can be predicated in 



