shown
to fill up or diminish, to any appreciable extent, the structural
interval which exists between Man and the man-like apes? Or, on the
other hand, does neither depart more widely from the average structure
of the human cranium, than normally formed skulls of men are known to do
at the present day?

It is impossible to form any opinion on these questions, without some
preliminary acquaintance with the range of variation exhibited by human
structure in general--a subject which has been but imperfectly studied,
while even of what is known, my limits will necessarily allow me to give
only a very imperfect sketch.

The student of anatomy is perfectly well aware that there is not a
single organ of the human body the structure of which does not vary, to
a greater or less extent, in different individuals. The skeleton varies
in the proportions, and even to a certain extent in the connexions, of
its constituent bones. The muscles which move the bones vary largely
in their attachments. The varieties in the mode of distribution of
the arteries are carefully classified, on account of the practical
importance of a knowledge of their shiftings to the surgeon. The
characters of the brain vary immensely, nothing being less constant than
the form and size of the cerebral hemispheres, and the richness of the
convolutions upon their surface, while the most changeable structures
of all in the human brain, are exactly those on which the unwise attempt
has been made to base the distinctive characters of humanity, viz. the
posterior cornu of the lateral ventricle, the hippocampus minor, and
the degree of projection of the posterior lobe beyond the cerebellum.
Finally, as all the world knows, the hair and skin of human beings may
present the most extraordinary diversities in colour and in texture.

So far as our present knowledge goes, the majority of the structural
varieties to which allusion is here made, are individual. The ape-like
arrangement of certain muscles which is occasionally met with* in the
white races of mankind, is not known to be more common among Negroes or
Australians: ([Footnote] *See an excellent Essay by Mr. Church on the
Myology of the Orang, in the 'Natural History Review', for 1861.) nor
because the brain of the Hottentot Venus was found to be smoother, to
have its convolutions more symmetrically disposed, and to be, so far,
more ape-like than that of ordinary Europeans, are we justified in
concluding a like co