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that Eskimo mothers apply lateral pressure to the skulls of their newly born children, and draw over them a tight-fitting leather cap to produce the desired pyramidal form. 27
Cranial measurements are as yet deficient from the want of a sufficient number of observations, which can be only increased by a continued augmentation of our collection of racial skulls. In this respect the greatest dispatch is urgently recommended, now that so many and various races are intermingling before our eyes.
Of the same importance as the transverse diameter is the height of the skull. For the purpose of determining it, Welcker placed one point of his calipers on the anterior margin of the occipital foramen, the other on the apex of the head, at the intersection of the planes which divide the skull into a right and left, and at the same time into an anterior and posterior half. 28 Here also the result of the measurement is expressed in the hundredth parts of the longitudinal diameter, and it is termed the index of height. By means of an instructive arrangement of Welcker,29 we perceive that on the average the height increases in inverse ratio to the breadth, so that narrow skulls are, generally speaking, high, and broad skulls flat; in other words, that in dolichocephali the index of height exceeds the index of breadth, and in brachycephali does not equal it, so that a smaller lateral extension is compensated by an increase in height. This ratio is however neither constant nor equal. The variation in the index of height is far smaller than that of breadth; it fluctuates between 70°2 and 82'4 for the index of height of 86-8 in the ancient Peruvians is suspected of artificial origin. Moreover, we find nations in which the index of height is far too small for that of breadth, such as the Hottentots, who, although dolichocephalic, only attain to an index of height of 702, whereas it ought to be at least three units higher.
27 Life with the Esquimaux, p. 520. 1865.
28 Alex. Ecker on the contrary measures first from the anterior and then from the posterior margins of the occipital foramen and the highest elevation of the occiput (Crania Germaniae merid. p. 3.) The mean between the two measurements would probably be the "height" most desirable for purposes of classification in the interest of ethnology.
29 Craniologische Mittheilungen, p. 154.
Index of Height.
On the other hand, the inhabitants of the island of Madura combine one of the greatest breadths of skull with the largest index of height, namely, 82'4, whereas we should expect one of about 75. Cases such as these furnish ethnology with excellent descriptive terms, enabling us to designate the Hottentots as flat narrow skulls (patystenocephali), the Malay inhabitants of Madura as high broad skulls (hypsibrachycephali). The index of breadth represents the shape of the skull as it appears when the brain-case is inspected from above, with the eye perpendicular to the central point of the longitudinal axis (Norma verticalis). The index of height, on the other hand, represents the view of the skull as seen from the back (Norma occipitalis). With similar indexes the outlines may, it is true, be sometimes angular, sometimes curvilinear; the greatest widths may occur sometimes in the middle and sometimes further back. The comparison of the figures of these measurements is nevertheless the only process which science has hitherto had at its disposal, while the selection of types by the eye would lead to artificial and arbitrary definitions.
II.—THE HUMAN BRAIN.
WHEN We separate the parts of a dissected head we acknowledge that we hold in our hands nothing but the shell of an exploded cartridge, or the larval husk from which the winged imago has escaped. We also understand that all cranial forms possess only an artificial value, and tell us nothing respecting the several grades of mental power contained within a dolichocephalic or brachycephalic bony covering. Artificial malformations of the brain-case by pressure of the infantine head, such as took place in the nations of olden times, and such as still occur among countless inhabitants of America, and is even the custom of foolish mothers in the north of France,' although perhaps not completely harmless, have not perceptibly impeded the healthy functions of the artificially remoulded apparatus of thought.
The brain, the noblest of our organs, varies in point of weight,
1 Ausland, 1866, p. 1095. Delineations of Artificial Compressions of the Skull.
from two or three to four pounds, while we find the brain of the elephant to be from 8-10 lbs., of the whale from 4-5 lbs., of a narwhal 18 feet in length 2 lbs. 15 oz., of a dolphin 7 feet long 2 lbs. "Who could venture," observes a celebrated French physiologist, "to infer from the bulk of brain, the nature and power of a human being or even of an animal?" Who, we might add, can judge by the weight whether a church clock or a pocket chronometer will keep the most accurate time? Yet both are merely the work of our own hands. Neither does man take the highest place in the relative weight of brain as compared to the total weight of the body, for although the brain of the whale is only 3300, that of the elephant 500, of the dog 230, while that of man is from 3 to 5 of the weight of the body, yet we are surpassed by the song-birds, among which the weight of the brain reaches 27, by the titmouse and the sparrow, in which it reaches respectively 12 and 27, and by the American apes, in which it amounts to from 2 to 13 of the weight of the body.2
Hence if the rank of the brain is to correspond to man's high rank in creation, we must look for differences other than those of weight. The human cerebrum, which can alone be considered the seat and organ of intellectual power, consists of an internal white substance traversed by delicate fibres, which is regarded as the conducting apparatus and focus of nervous action; and secondly, of an external grey covering in which granules, spherical forms, and ganglia may be recognized, and which is held to be, if not the originator, at least the seat of the psychical functions. The more profusely convoluted is the surface, and the more furrowed it appears, the more does the outer covering or grey substance increase in superficies.
We also know that more or less extensive disease of this outer layer is capable of destroying the higher functions of the mind, especially of co-ordinate thought. It was therefore obviously permissible to recognize the abundance of convolutions as a sign of the superior rank of the brain, particularly as the elephant, the most intelligent of all animals, affords a good example of a
2 Th. Bischoff in the Naturwissenschaftlichen Vorträgen Münchener Gelehrten, p. 139. Munich, 1858.
Weight of Brain.
brain deeply furrowed by multiform convolutions. The primary distribution of the furrows, observes A. Ecker, seems to be generally symmetrical, and asymmetry is prevalent only in the the secondary furrows; so that greater symmetry in the furrows and convolutions may be regarded as the expression of arrested development, especially as the brain of idiots displays this character. 3 On the other hand, Rudolph Wagner points out that the brain of the dog, when compared with the complex system of convolutions of the unintelligent sheep, exhibits an extraordinary poverty, and that the brains of our great mathematicians, Gauss and Dirichlet, were without any peculiar folds, although among the most richly endowed of any that he has seen in point of depth and multiformity of the furrows, especially in the frontal regions.
Huxley was able to pour 553 cubic inches of water into the brain-case of a woman of sound mental powers, and 34 cubic inches into the most capacious cranium of a gorilla; 5 but it should first have been ascertained whether the brains of men and apes are so strictly analogous as to justify this comparison in point. of size. Unfortunately, investigations respecting the embryonic brain of the ape are still very meagre. Von Bischoff has nevertheless announced his conviction that although the human brain possesses no important furrow and no important convolution which is not represented in the orang, yet the human brain by no means exhibits a mere advance, and the brain of the orang an arrest of growth, but that they each take a different course of evolution, developing in different directions, and at no time coin
3 Archiv für Anthrop. vol. iii. p. 221.
Wagner, Wendungen der Hemisphären, pp. 6, 7, and 24.
5 He reckons 2525 gr. of brain = to I cubic inch of water (Man's Place in Nature). Carl Vogt (Archiv für Anthropologie, vol. iii. 186) more precisely estimates the average capacities of the interior of the skulls of the higher apes
ciding with one another. This is, as yet, merely the conviction of a scholar highly esteemed by his compeers, but at the same time it corresponds with our expectations. It is a common experience that diseases still latent in the parents at the time of procreation, and only breaking out at a much later period, are nevertheless transmitted to their children, to make their appearance in them also only at a mature age. Hence, if even the causes of future disturbances are hereditary, specific, generic and ordinal differences must be still more so. It is therefore impossible to free one's self of the idea that even at the first awakening of life, the morphological end is preordained for the human germ as well as for that of the ape. Their development may be compared with two lines of rails which long run side. by side on the same track, and finally separate right and left in different curves. Bischoff moreover admits that by reason of their great morphological proximity, it requires the closest examination to recognize differences between the brains of man and of the orang, the chimpanzee and the gorilla. Relying on Rolleston's measurements, Bischoff considers that the hemispheres of the human cerebrum are specially distinguished from those of the apes by their superior height. To ascribe little importance to differences in quantity, is to overlook the fact that in chemical compounds the quality of the combinations is dependent on the quantity that by the addition of a single atom of oxygen, sulphurous acid is converted into sulphuric acid, that a numerical increase in frequency transforms dark into luminous vibrations, that is to say, changes the temperature which excites the visual nerves; and that even in numbers slight changes of quantity lead to differences of great importance." In the obscurity which still prevails as to the relations of the several portions
The relative difference in quantity between the numbers
is very slight; yet the first possesses the property of diminishing to infinity when persistently raised to higher powers, while by the same process the third increases to infinity, and the middle one remains constant at every power.