CLASSIFICATION. 411 



connect together all languages, extinct and recent, by the 

 closest affinities, and would give the filiation and origin of 

 each tongue. 



In confirmation of this view, let us glance at the classifi- 

 cation of varieties, which are known or believed to be de- 

 scended from a single species. These are grouped under 

 the species, with the sub-varieties under the varieties ; and 

 in some cases, as with the domestic pigeon, with several 

 other grades of difference. Nearly the same rules are fol- 

 lowed as in classifying species. Authors have insisted on 

 the necessity of arranging varieties on a natural instead of 

 an artificial system ; we are cautioned, for instance, not to 

 class two varieties of the pineapple together, merely be- 

 cause their fruit, though the most important part, happens 

 to be nearly identical ; no one puts the Swedish and com- 

 mon turnip 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 agri- 

 culturist Marshall says the horns are very useful for this 

 purpose with cattle, because they are less variable than the 

 shape or color of the body, etc. ; whereas with sheep the 

 horns are much less serviceable, because less constant. In 

 classing varieties, I apprehend that if we had a real pedi- 

 gree, a genealogical classification would be universally pre- 

 ferred ; and it has been attempted in some cases. For we 

 might feel sure, whether there had been more or less modi- 

 fication, that the principle of inheritance would keep the 

 forms together which were allied in the greatest number 

 of points. In tumbler pigeons, though some of the sub- 

 varieties differ in the important character of the length of 

 the 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 thought on 

 the subject, these tumblers are kept in the same group, 

 because allied in blood and alike in some other respects. 



With species in a state of nature, every naturalist has in 

 fact brought descent into his classification ; for he includes 

 in his lowest grade, that of 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 common of the adult males and 

 hermaphrodites of certain cirripedes, and yet no one dreams 

 of separating them. As soon as the three Orchidean forms, 

 Monachanthus, Myanthus, and Catasetum, which had pre- 



