d been simply written down in a linear series the
representation 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 ranking them under different so-called genera,
subfamilies, 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 intermediate 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, whilst
others had altered much owing to the spreading, isolation and state of
civilisation 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 subordinate to groups; but the proper or even the only possible
arrangement would still be genealogical; and this would be strictly
natural, 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 subvarieties
under the varieties; and in some cases, as with the domestic pigeon,
with several other grades of difference. Nearly the same rules are
followed 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 pine-apple 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. Whatever part is