MUTUAL AFFINITIES OF ORGANIC BEINGS 379 



diagram on a flat surface, is much too simple. The branches 

 ought to have diverged in all directions. It the names of the 

 groups had been simply written down in a linear series, the repre- 

 sentation would have been still less natural; and it is notoriously 

 not possible to represent in a series, on a flat surface, the affinities 

 which we discover in nature among the beings of the same group. 

 Thus, the natural system is genealogical in its arrangement, like a 

 pedigree. But the amount of modification which the different 

 groups have undergone has to be expressed by rankmg them 

 under different so-called genera, sub-families, families, sections, 

 orders, and classes. 



It may be worth while to illustrate this view of classification, by 

 taking the case of languages. If we possessed a perfect pedigree of 

 mankind, a genealogical arrangement of the races of man would 

 afford the best classification of the various languages now spoken 

 throughout the world; and if all extinct languages, and all inter- 

 mediate and slowly changing dialects, were to be included, such an 

 arrangement would be the only possible one. Yet it might be that 

 some ancient languages had altered very little and had given rise 

 to few new languages, while others had altered much, owing to the 

 spreading, isolation, and state of civilization of the several co- 

 descended races, and had thus given rise to many new dialects and 

 languages. The various degrees of difference between the languages 

 of the same stock would have to be expressed by groups subordi- 

 nate to groups ; but the proper or even the only possible arrange- 

 ment would still be genealogical; and this would be strictly nat- 

 ural, as it would 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 classification of 

 varieties, which are known or believed to be descended from a 

 single species. These are grouped under the species, with the sub- 

 varieties under the varieties; and in some cases, as with the do- 

 mestic pigeon, with several other grades of difference. Nearly the 

 same rules are followed as in classifying species. Authors have in- 

 sisted 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 because their fruit, 

 though the most important part, happens to be nearly identical; 

 no one puts the Swedish and common turnip together, though the 

 esculent and thickened stems are so similar. WTiatever 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 



I 



