e embodiment of a distinct and tangible idea. So, too,
of the lesser groups or orders within each class, and of the still more
subordinate groups, named technically families, genera; and, finally,
the individual species. That the grouping of species into these groups
was more or less arbitrary was of course to some extent understood, yet
it was not questioned by the general run of zoologists that a genus,
for example, represented a truly natural group of species that had been
created as variations upon one idea or plan, much as an architect
might make a variety of houses, no one exactly like any other, yet all
conforming to a particular type or genus of architecture--for example,
the Gothic or the Romanesque. That each of the groups defined by the
classifiers had such status as this was the stock doctrine of zoology,
as also that the individual species making up the groups, and hence
the groups themselves, maintained their individual identity absolutely
unaltered from the moment of their creation, throughout all successive
generations, to the end of their racial existence.

Such being the fundamental conception of zoology, it remained only for
the investigator to study each individual species with an eye to
its affinities with other species, that each might be assigned by a
scientific classification to the particular place in the original scheme
of creation which it was destined to occupy. Once such affinities
had been correctly determined and interpreted for all species, the
zoological classification would be complete for all time. A survey of
the completed schedule of classification would then show at a glance the
details of the preconceived system in accordance with which the members
of the animal kingdom were created, and zoology would be a "finished"
science.

In the application of this relatively simple scheme, to be sure, no end
of difficulties were encountered. Each higher animal is composed of so
many members and organs, of such diverse variations, that naturalists
could never agree among themselves as to just where a balance of
affinities between resemblances and differences should be struck;
whether, for example, a given species varied so much from the type
species of a genus--say the genus Gothic house--as to belong properly
to an independent genus--say Romanesque house; or whether, on the other
hand, its divergencies were still so outweighed by its resemblances as
to permit of its retention as an aberrant