which establish a type serve to connect it insensibly with those of
another. Hence the great difficulty experienced in attempting to
classify the members of the Human Family. The discrepancy of
opinion has extended not only to the number of divisions to he
made, hut also to the particular races which should he assigned to
each division. Blumenhach long ago expressed this difficulty. We
have only to examine the list of writers who have attempted the
classification of Human Races, and observe how they differ in the
number of their primary departments, to he convinced of the prematureness
of the whole attempt, and the scanty scientific data upon
which such very artificial divisions have been erected. It appears to
me that much of the difficulty arises from the scanty information
which we possess concerning the number of primaeval cranial fypes,
the number of naturally divergent forms of each of these, and the
degree of divergency permitted, and lastly, the tests by which to
discriminate between forms naturally aberrant, and those hybrid
results of blood-crossing. The study of divergent forms is of great
importance, since in their varied hut limited deviations from the
type — like all exceptions to general rules — they indicate the
essentials of the type while demonstrating a serial, archetypal unity
of the human family in keeping with the entire animal world. To
speak, therefore, of “ developing the limits of a variety,” is simply
to demonstrate the connections, relations, and persistence of those
varieties. The diversities of cranial form presented by any nation
or tribe should therefore be regarded as the radii, so to speak, by
which that tribe is connected with the rest of the humanitarian
series, whether living or extinct, or, in the course of future geological
changes, yet to appear.
It is well known that naturalists rely mainly upon form, color,
proportions — the externals, in short—to establish species. The
illustrious C u v ie r , taking higher ground, attempted to develope the
laws of classification by a resort to the comparative method in anatomy.
With the osteological branch of this method, as an instrument
of research, he undertook his grand scheme of the restoration
of the fossil world and the determination of its relation to the living
zoology. His reliance upon internal structure in preference to
external characters, was as much a matter of necessity as of choice,
since of the palaeontological objects of his study, the bony skeleton
and the teeth alone remained from which to recompose the forms
of the past animal world, and determine their species. In the course
of his investigations a remarkable fact became evident — that in
many genera of animals, species externally well characterized, differed
scarcely at all in their bony frame-work. Regarding these
slight differences by such a practised eye certainly not overlooked—
as trivial, and losing sight of the singular importance
they derive from their historical permanency, he was led in the end
to deny to comparative osteology the value he first assigned it.
Thus, notwithstanding his great scientific labors, he left it undecided
whether the fossil horse was specifically identical with the
living or not.70 On this point naturalists still differ in opinion.
Whilst by the aid of comparative anatomy — for the cultivation
of which he enjoyed unusual advantages —he was enabled to startle
the world with the brilliant announcement that there had been
several zoological creations, of which man was one, we find him at
length hesitatingly denying to anatomical characters the power of
determining species. But the question arises — a question already
perceived and disposed of in the affirmative by some ethnologists__
whether anatomical characters have not a higher signification than
the mere determination of species; whether, in fact, they are not
generic. It would, indeed, appear, that while the external or peripheral
form and appendages determine species, the internal organism
establishes genera. But the genus must contain within itself and
foreshadow the essential characters of the species 5 there must be an
adaptation between the peripheral conformation and central organic
structure. As a very slight error committed in the first step of a
long and complicated mathematical calculation magnifies itself at
every subsequent step of the process, until a result is obtained very
different from the true one, so a comparatively minute peculiarity in
the osseous structure, of an animal may repeat itself through the
muscles, fascia, and integumentary covering, expressing itself at last
as a characteristic, which, though it might he difficult to point out
exactly, is seen to he an individual or specific mark by which
the animal may be discriminated from other individuals or from
allied species. And as the result of the supposed problem must
always be the same, so long as the incorporated error is not eliminated,
so the external peculiarity of the animal must ever remain the
same, while the internal structure mark varies not. This constant
and historically immutable relation between structure and form is in
consonance, with the law of the “ correlation of forms,” first suggested,
I believe, by Cuvier, and by him used in such a masterly
manner in the elucidation of the laws of zoology.
“ The. importance to be attached to the zoological characters
afforded by the slighter modifications of structure,” writes M a r t in ,
“ rises as we ascend, in the scale of being. In the arrangement of
70 Discours sur les Revolutions du Globe, p. 76.