its organization. In attaining this high development, it passes successively
through the forms which belong permanently to fishes, reptiles,
birds, mammals, Negroes, Malays, Americans, and Mongolians.
The bony structure undergoes similar alterations, “ One of the earliest points where
ossification commences is the lower- jaw. This bone is therefore sooner completed than
any other of the head, and acquires a predominance which it. never loses in the Negro.
During the soft, pliant state of the bones of the skull, the oblong form which they naturally
assume approaches nearly the permanent shape of the American. At birth, the flattened
face and broad, smooth forehead of the infant; the position of the eyes, rather towards the
sides of the head, and the widened space between, represent t h e Mongolian form, which,
in the Caucasian, is not obliterated but by degrees, as the child advances to maturity»”
Hamilton Smith, commenting upon these interesting researches, says : “ Should the conditions
of cerebral progress be more complete at birth in the Caucausian type, and be
successively lower in the Mongolie and intermediate Malay and American, with the woollyhaired
least developed of all, it would follow, according to the apparently general law of
progression in animated nature, that both — or at least the last-mentioned ^wbuld be in
the conditions which show a more ancient date of existence than the other, notwithstanding
that both this and the Mongolie are so constituted that the spark of mental development
can be received by them through contact with the higher Caucasian innervation; thus
appearing, in classified zoology, to constitute perhaps three species, originating at different
epochs, or simultaneously in separate regions; while, by the faculty of fusion which the
last, or Caucasian, imparted to them, progression up to intellectual equality would manifest
essential unity, and render all alike responsible beings, according to the degree of their
existing capabilities —- for this must be the ultimate condition for which Man is created.” 80
Prom his own researches, Prof. A gassiz concludes that it is impossible,
in the foetal state, to detect the anatomical marks which are
characteristic of species. These specific marks he assures us become
manifest as the animal, in the course of its development, approaches
the adult state. In like manner, the evolution of the physical and
mental peculiarities of the different rapes of men appears to commence
at the moment of birth. Dr. K nox, in his recent communications
in the “London Lancet,” already referred to, maintains almost
the same opinion. He considers the embryo of any species of any
natural family as the most perfect of forms, embracing within itself,
during its phases of development, all the forms or species which that
natural family can assume or has assumed in past time. “ In the
embryo and the young individual of any species of the natural
family of the Salmonidæ, for example,” says he, “ you will find the
characteristics of the adult of all the species. The same, I believe,
holds in man ; so that, were all the existing species of any family to
he accidentally destroyed, saving one, in the embryos and young of
that one will be found the elements of all the species ready to reappear
to repeople the waters and the earth, the forms they are to
assume being dependent on, therefore determined by, the existing
order of things. With another order will arise a new series of
species, also foreseen and provided for in the existing w;orld.”
“ Nat. Hist, of the Human Species, pp. 176-7. See also Serres’ Anatomie Comparée.
If we carefully consider the development of the cranium, it will
be seen that this development goes on between, and is modified by
two systems of organs — externally the muscular, internally the
nervous. The brain exerts a double influence, mechanically or
passively by its weight, and actively by its growth. That the brain
completely fills its bony case, is sufficiently well known from the fact
of the impressions left upon the inner aspect of the cranium by the
cerebral convolutions and vessels. Very slight allowance need be
made for the thickness of the meninges. That the progressive
development of the brain is really capable of exerting some force
upon the cranial bones surrounding it, is shown in the records of
cases of hypertrophy of that organ, where, 'upon post-mortem examination,
the calvaria being removed, the spongy mass has protruded
from the opening and could not be replaced. That the bones are
capable of yielding to a distending force acting from within outwards,
is shown in the cases of chronic hydrocephalus, where the
ventricles are found full of water, the brain-tissue flattened out, and
the bones greatly distorted. Such a force becomes perceptible in
proportion to the degree of softness and pliancy of the bones. A
cheeky to its action will be found in the sutures and in the amount
of resistance offered by the dura-mater. How it must be obvious
that as long as the sutures remain open, and the developmental
activity of the brain continues, the head must enlarge. If all the
sutures remain open, this development will be regular and in exact
proportion to the activity of growth manifested by the different parts
of the encephalon. When a suture closes, further development in
that direction will in great measure terminate. Of this proposition
Dr. M orton gives us the following example:
“ I have in my possession,” says he, “ the skull of a mulatto boy, who died at the age
ot eighteen years. In this instance, the sagittal sutnre is entirely wanting; in consequence,
the lateral expansion of the cranium has ceased in infancy, or at whatever period
the suture became consolidated. Hence, also, the diameter between the parietal protuberances
is less than 4.5 inches, instead of 5, which last is the Negro average. The squamous
sutures, however, are fully open, whence the skull has continued to expand in the upward
direction, until it has reached the average vertical diameter of the Negro, or 5.5 inches.
The coronal suture is also wanting, excepting some traces at its lateral termini; and the
result of this last deficiency is seen in the very inadequate development of the forehead,
which is low and narrow, but elongated below, through the agency of the various craniofacial
sutures. The lambdoidal suture is perfect, thus permitting posterior elongation;
and the growth in this direction, together with the full vertical diameter, has enabled the
brain to attain the bulk of — oubic inches, or about — less than the Negro average. I believe
that the absence or partial development of the sutures may be a cause of idiocy by checking
the growth of the brain, and thereby impairing or destroying its functions.” «!
81 See a paper on the Size of the Brain in the Various Races and Families of Man; with
Ethnological Remarks; by Samuel George Morton, M. D .: published in “ Types of'Mankind,”
by Nott and Gliddon, Philadelphia, 1854, p. 303, note. See also Proceedings of Phila
-icad. Nat. Sci. for August, 1841.