Chapter VIII: Relative Racial Brain-Weight and Size (1)

CONSISTENTLY with the recognition of the brain as the organ of intellectual activity, it seems not unnatural to assume for man, as the rational animal, a very distinctive cerebral development. One of the most distinguished of living naturalists, Professor Owen, has even made this organ the basis of a system of classification, by means of which he separates man into a sub-class, distinct from all other mammalia. But while a comparison between man and the anthropoid apes, as the animals most nearly approximating to him in physical structure, lends confirmation to the idea not only that a well-developed brain is essential to natural activity, but that there is a close relation between the development of the brain and the manifestation of intellectual power; the distinctive features in the human brain, as compared with those of the anthropomorpha, prove to be greatly less than had been assumed under imperfect knowledge. The substantial difference is in volume. “No one, I presume,” says Darwin, “doubts that the large size of the brain in man, relatively to his body, in comparison to that of the gorilla or orang, is closely connected with his higher mental powers”;[152] and it might not unfairly be reasoned from analogy, that the same test distinguishes the intellectual man from the stolid, and the civilised man from the savage. A careful study of the subject, however, shows some remarkable deviations from such a scale of progression. Attention is indeed directed to greatly more ample proofs of inequality between the organic source of power and the manifestations of mental energy; as, for example, in the ant, with its cerebral ganglia not so large as the quarter of a small pin’s head, displaying instincts and apparent affections of wonderful intensity and compass. Viewed in this aspect, “the brain of an ant is one of the most marvellous atoms of matter in the world, perhaps more marvellous than the brain of man.” Here, however, we look on elements of contrast rather than analogy; and seek in vain in this direction for any appreciable test of the soundness of the popular belief in the size of the brain as a measure of intellectual power. It is otherwise when we turn to the anthropomorpha. There, alike in the scientific and in the popular creed, very special and exceptional affinities to man are admitted; and a careful study of their anatomical structure tends to increase the recognised points of analogy.

Mr. Lockhart Clarke, in a contribution to Dr. Maudsley’s work on the Physiology and Pathology of Mind, gives a minute description of the concentric layers of nervous substance which combine to form the convolutions of the human brain; and of the forms and disposition of the various nerve-cells of which its vesicular structure consists. Comparing the human brain with those of other animals, he says: “Between the cells of the convolutions in man and those of the ape tribe I could not perceive any difference whatever; but they certainly differ in some respects from those of the larger mammalia: from those, for instance, of the ox, sheep, or cat.”[153] Apart from the difference in volume (55 to 115 cubic inches), the only distinctive features, according to Professor Huxley, between the brain of the anthropomorpha and that of man, are “the filling up of the occipito-temporal fissure; the greater complexity and less symmetry of the other sulci and gyri; the less excavation of the orbital face of the frontal lobe; and the larger size of the cerebral hemispheres, as compared with the cerebellum and the cerebral nerves.”

The brain of the orang is the one which seems most nearly to approximate to that of man. In volume it is about 26 or 27 cubic inches; or about half the minimum size of a normal human brain. The frontal height is greater than in that of other anthropomorpha; the frontal lobe is in all respects larger as compared with the occipital lobe; and certain folds of brain-substance, styled “bridging convulsions,” which in the human brain are interposed between the parietal and occipital lobes, also occur, though greatly reduced, in the brain of the orang; while they appear to be wholly wanting in the chimpanzee, the gibbon, and other apes which superficially present a greater resemblance to man. Referring to the convolutions of the central cerebral lobe, Huschke says: “With their formation in the ape, the brain enters the last stage of development until it arrives at its perfection in man”; and the higher class of brains may be arranged between the extremes of poorly and richly convoluted examples.

But it must not be overlooked that, apart from structural differences, relative, and not absolute mass and weight of brain has to be considered, otherwise the elephant and the whale would take the foremost place. “The brain of the porpoise,” Professor Huxley remarks,[154] “is quite wonderful for its mass, and for the development of the cerebral convolutions”; but it is the centre of a nervous system of corresponding capacity, while as compared with the size of the animal, the brain is not relatively large. Vogt states the weight of the human body to be to the brain, on an average, as 36 to 1; whereas in the most intelligent animals the difference is rarely less than 100 to 1.

Assuming the existence of some uniform relation between the size of the brain and the development of the intellectual faculties, along with whatever is recognised as most closely analogous to them in the lower animals, it might be anticipated that we should find not only a graduated development of brain in the anthropomorpha as they approximate in resemblance to man; but, still more, that the progressive stages from the lowest savage condition to that of the most civilised nations should be traceable in a comparative size and weight of brain. Dr. Carl Vogt, after discussing certain minor and doubtful exceptions, thus proceeds: “We find that there is an almost regular series in the cranial capacity of such nations and races as, since historic times, have taken no part in civilisation. Australians, Hottentots, and Polynesians, nations in the lowest state of barbarism, commence the series; and no one can deny that the place they occupy in relation to cranial capacity and cerebral weight corresponds with the degree of their intellectual capacity and civilisation.”[155] But the position thus confidently assigned to the Polynesians receives no confirmation from the evidence supplied by the measurements of Dr. J. B. Davis, in his _Thesaurus Craniorum_; and a careful study of the subject reveals other remarkable deviations from such a scale of progression, not only in individuals but in races. To these exceptional deviations, with their bearing on the comparative capacity of races, the following remarks are chiefly directed. The largest and heaviest brains do indeed appear, for the most part, to pertain to the nations highest in civilisation, and to the most intelligent of their number. But this cannot be asserted as a uniform law, either in relation to races or individuals. The more carefully the requisite evidence is accumulated, the less does it appear that the volume of brain, or the cubic contents of the skull, supply a uniform gauge of intellectual capacity. In the researches which have thus far been instituted into the characteristics of the human brain among the lowest races, the development is in many respects remarkable; and, as was to be expected, no organic differences between diverse races of men have been traced.

Professor C. Luigi Calori has published the results of a careful examination of the brain of a negro of Guinea. It presented the marked excess of length over breadth so characteristic of the negro cranium; but in other respects it corresponded generally to the fully developed European brain. The distribution of the white and gray substances was the same; the cerebral convolutions were collected into an equal number of lobes; and the only special difference was that the convolutions were a little less frequently folded, and the separating sulci somewhat less marked than in the average European brain. But even in those respects the complication was great. The actual weight of the brain, according to Professor Calori, was 1260 grammes, equivalent to 44.4 cubic inches. The complexity of convolution, and consequent extension of superficies of the encephalon, appears to be an essential element in the development of the brain as the organ of highest mental capacity; and to the cerebrum, apparently, the true functions of intellectual activity pertain. Professor Wagner undertook the measurement of the convex surface of the frontal lobe in a series of brains. The heaviest, as a rule, had also the greatest development of surface. But the two elements were not in uniform ratio. Some of the lighter brains presented a much greater degree of convolution and consequent extent of convex superficies than others which ranked above them in weight. It is thus apparent that in estimating the comparative characteristics of brains, various elements are necessary for an exhaustive comparison. Besides the functional differences of the cerebrum, cerebellum, and pons varolii, they have different specific gravities, so that brains of equal weight may differ widely in quality. Dr. Peacock, taking distilled water as 1000, gives the values of the subdivisions of the brain thus: cerebrum, 1034; cerebellum, 1041; pons varolii, 1040. Again, Dr. Sankey states the mean specific gravity of the gray matter of the brain in either sex as 1034.6, and of the white matter as 1041.2. The variations from these results, as given by Bastian, Thurnam, and others, are trifling. But it is significant to note that recent researches show that where greater specific gravity of brain occurs in the insane, it appears to be limited to the gray matter.[156] Professor Goodsir maintained that symmetry of brain has more to do with the higher faculties than bulk of form. It is, at any rate, apparent that two brains of equal weight may differ widely in quality.

Nevertheless, the popular estimate embodied in such expressions as “a good head,” “a long-headed fellow,” and “a poor head,” like many other popular inductions, has truth for its basis. Up to a certain stage the growth of the brain determines the capacity of the skull. Then it seems as though more complex convolutions accompanied the packing of the elaborated cerebral mass within the fixed limits of its osseous chamber.

A comparison of races, based on minute investigation of an adequate number of brains of fair typical examples, may be expected to yield important results; but in the absence of such direct evidence, the chief data available for this purpose are derived from measurements of the internal capacity of their skulls. Among English observers who have devoted themselves to this class of observations, the foremost place is due to Dr. J. Barnard Davis, who, in 1867, summed up the results of his extensive researches in a contribution to the Royal Society, entitled “Contributions towards determining the Weight of the Brain in different Races of Man.”[157] Inferior as such evidence must necessarily be, if compared with the examination of the brain itself, nevertheless the number of skulls of the different races gauged unquestionably furnishes some highly valuable data for ethnical comparison. The evidence, moreover, is obtained from a source in some respects less variable than the encephalon; and will always constitute a corrective element in estimating results based on direct examinations of the brain. Dr. Davis, indeed, claims “that the examination of a large series of skulls in ascertaining their capacities and deducing from those capacities the average volume of the brain, affords in some respects more available data for determining this relative volume for any particular race than the weighing of the brain itself.” The defect is, that its most important results are necessarily based on the assumption of a uniform density of brain; whereas some notable ethnical differences, hereafter referred to, may prove to be due to the fact that certain races derive their special characteristics from a prevailing diversity in this very respect.

But the extensive observations of Dr. Davis, as of Dr. Morton, have a special value from the fact that each furnishes results based on a uniform system of observation; for the diverse methods and materials employed by different observers in gauging the human skull have greatly detracted from their practical value. In a communication by the late Professor Jeffreys Wyman to the Boston Natural History Society,[158] he presented the results of a series of measurements of the internal capacity of the same skull with pease, beans, rice, flax-seed, shot, and coarse and fine sand. From repeated experiments he arrived at the conclusion that the apparent capacity varied according to the different substances used, so that the same skull measured respectively, with pease 1193 centimetres, with shot 1201.8, with rice 1220.2, and with fine sand 1313 centimetres. Professor Wyman was led to the conclusion that, for exactness, small shot, as employed latterly by Dr. Morton, is preferable to sand, were it not for its weight, which, in the case of old and fragile skulls, is apt to be destructive to them. With a view to avoid the latter evil, Dr. J. B. Davis has used fine Calais sand of 1.425 specific gravity. The diversity in apparent volume, consequent on the employment of different substances in gauging the internal capacity of the skull, necessarily detracts from the value of comparative results of Morton, Davis, and others. But the elaborate measurements of their great collections of human crania furnish reliable series of data, each uniform in system, and sufficiently minute to satisfy many requirements of comparative craniometry and approximate cerebral development.

Without assuming an invariable correspondence in cubical capacity and brain-weight, there is a sufficient approximation in the cubical capacity of the skull and the average weight of the encephalon to render the deductions derived from gauging the capacities of skulls of different races an important addition to this department of comparative ethnology. For minute cerebral comparisons, however, it is apparent that much more is required; and the special functions assigned to the various organs within the cranium have to be kept in view. Of these the medulla oblongata, in direct contact with the spinal cord, is now recognised as the centre of the vital actions in breathing and swallowing; and is believed also to be the direct source of the muscular action employed in speech. Next to it are the sensory ganglia, arranged in pairs along the base of the brain. To the cerebellum, which the phrenologist sets apart as the source of the emotions and passions embraced in his terminology of amativeness, philoprogenitiveness, etc., physiologists now assign the function of conveying to the mind the conditions of tension and relaxation of the muscles, and so controlling their voluntary action. But above all those is the cerebrum, or brain-proper, consisting of two large lobes of nervous substance, which in man are so large that, when viewed vertically, they cover and conceal the cerebellum. To this organ is specially assigned emotion, volition, and ratiocination. It is the assumed seat of the mind; and, in a truer sense than the skull—

The dome of thought, the palace of the soul;

if indeed it be not, to one class of reasoners, the mind itself. Certain it is that no acute disease can affect it without a corresponding disorder of the functions of mind; and with this organ much below the average size, intellectual weakness may always be predicated. But at the same time, it is significant to note that the human brain, stinted in its full proportions, and reduced to a seeming equality with the anthropomorpha, exhibits no corresponding capacities or instincts in lieu of the higher mental qualities. Microcephaly is the invariable index, not of mere limited intelligence and mental capacity, but of actual mental imbecility. If the augmentation of the brain of the anthropomorpha from 55 to 115 cubic inches be all that is requisite for the transformation of the irrational ape into the reasoning man, it would seem to be in no degree illogical to look for the accompaniment of the inversion of the process by an approximation, in some instances, to certain capacities and functions of the ape. But there are no indications of this. In some examples of microcephaly, the so-called animal propensities do indeed manifest themselves to excess; but there is no reproduction of the animal nature, instincts, or capacities, analogous to the scale of cerebral development of the orang or chimpanzee. A microcephalous idiot, who died at the age of twenty-two, in St. Bartholomew’s Hospital, London, had a brain weighing only 13.125 oz., or 372 grammes. In describing this case, Professor Owen remarks: “Here nature may be said to have performed for us the experiment of arresting the development of the brain almost exactly at the size which it attains in the chimpanzee, and where the intellectual faculties were scarcely more developed. Yet no anatomist would hesitate in at once referring the cranium to the human species.” And so is it with the encephalon. The brain of the chimpanzee is a healthy, well-developed organ, adequate to the amplest requirements of the animal; whereas the microcephalous human brain is inadequate for any efficient, continuous cerebral activity: not merely limited in its range of powers. Much, however, may yet be learned from a careful attention to the imperfect manifestations of activity in certain directions, in cases of microcephalic idiocy, and noting the predominant tendency in each case, with a view to subsequent examination of the brain. By this means it may be found possible to refer certain forms of mental activity to special variations in the structure of the organ, or to distinct members of the encephalon.

Dr. Laennec exhibited to the Anthropological Society of Paris a microcephalous idiot of the male sex, aged fourteen years. “This child is entirely unconscious of his own actions, and his intellectual operations are very few in number, and very rudimentary. His language consists of two syllables, _oui_ and _la_, and he takes an evident pleasure in pronouncing them. He takes no heed in what direction he walks. He would step off a precipice, or into a fire.” Attention was specially directed to the idiot’s hands: “The thumbs are atrophied, and cannot be opposed to the other fingers. The palms of the hands have the transverse creases, but not the diagonal—the result of the atrophy of the thumbs. Hence the hand resembles that of the chimpanzee. The dentition too is defective. Though fourteen years of age, the child has only twelve teeth.” Here it is curious to note the analogies in physical structure to the lower anthropomorpha in other organs besides the brain, for it only renders more striking the absence of any corresponding aptitudes.

Dr. J. Barnard Davis, in his interesting monograph on _Synostotic Crania among Aboriginal Races of Man_, produces some remarkable illustrations of the effect of premature ossification of the sutures of the skull in arresting the full development of the brain, and so rendering it unequal to the due performance of its functions. “I have,” he says, “the cranium of a convict who was executed on Norfolk Island, which I owe to the kindness of Admiral H. M. Denham. This man was executed there when that beautiful isle was appropriated to the reception of the most dangerous and irreclaimable convicts from the other penal settlements. It is a microcephalic skull, rather dolichocephalic, of a man apparently about forty years of age. It exhibits a perfect ossification of the sagittal and of the greater portion of the lambdoidal sutures. The coronal suture is partially obliterated at the sides in the temporal regions, and can only be distinguished by faint traces in all its middle parts. In this case there has not been any compensatory development of moment in other directions. The calvarium is not abridged in its length, which is 7.1 inches, equal to 179 millimetres; probably it is a little elongated. It is, however, very narrow being only 4.8 inches, or 122 mm. at its widest part, between the temporal bones. So that the result is a very small, dwarfed, almost cylindrical calvarium. The internal capacity is only 59 ounces of sand,[159] which is equal to 71.4 cubic inches, or 1169 cubic centimetres.” Here is a skull considerably below the lowest mean of the crania of any race in Morton’s enlarged tables, or in the more comprehensive ones furnished in Dr. Davis’s _Thesaurus Craniorum_. Another skull nearly approximating to it is that of a Cole, one of the savage tribes of Nagpore, in Central India, who are said to go entirely naked. It is described in the supplement to the _Thesaurus Craniorum_ as that of “Chara,” a Cole farmer, aged fifty, and its internal capacity is stated as 59.5 oz. av., equivalent to 71.7 cubic inches. The Coles appear to be small of stature. The heights of three of them, whose skulls are in the same collection, were respectively 5 ft. 5 in., 5 ft. 2 in., and 5 ft., and the average internal capacity of five male skulls is only 66.6. The small stature in this and others of the native races of Central India, has to be taken into account in estimating the relative size of the brain. But, after making all due allowance for this, the Cole skulls are remarkable for their small size, being smaller even than the ordinary Hindoos of Bengal. Yet one of them, “Cootlo,” whose skull is among those included in the above mean, commanded a band of insurgents in the Porahant rebellion of 1858, and made himself a terror to the district.

The microcephalism of races, as well as of individuals, of small stature, must not be confounded with the true microcephaly of a dwarfed or imperfectly developed brain, which is invariably accompanied with mental imbecility. The Mincopies of the Andaman Islands are spoken of by Professor Owen as “perhaps the most primitive, or lowest in the scale of civilisation, of the human race.”[160] Mr. G. E. Dobson, in describing his first visit to one of their “homes,” says: “Although none of the tribe exceeded 64 inches in height, so that on first seeing them we thought the shed contained none but boys and girls, I was especially struck by the remarkable contrast between the size of the males and females.”[161] Dr. J. B. Davis has given, in the supplement to _Thesaurus Craniorum_, the dimensions of a male Mincopie skeleton in his collection. The age he assumes to have been about thirty-five. The internal capacity of the skull is 62 oz. (Calais sand), equivalent to 75.5 cubic inches, and the entire height of the skeleton is 58.7 inches. It belongs, says Dr. Davis, to a pigmy race, is small in all its dimensions, and is particularly small in the dimensions of the pelvis. Of their skulls, moreover, he adds, “it is somewhat difficult to determine the sex with confidence. They are all small (but this is a character of the race), they are delicate in development, and they have that fulness of the occipital region, and smallness of the mastoid processes, which are marks of femininism.”

Mr. Alfred R. Wallace connects the Mincopies with the Negritos and Semangs of the Malay peninsula, a dark woolly-haired race, dwarfs in stature. Dr. Davis says of the six Mincopie skulls in his collection, four male and two female, as well as of others which he has seen: “They are all remarkably and strikingly alike, not merely in size but in form also. They are all small, round, brachycephalic crania of beautiful form.” Moreover, though classed as “lowest in the scale of civilisation,” the Mincopies betray no deficiency of intellect. The admirable photographs which illustrate Mr. Dobson’s narrative show in the majority of them good frontal development. The brain is not, indeed, relatively small. Their canoes are made of the trunk of a tree, hollowed out; and Mr. Dobson remarks: “The construction of their peculiar arrows and fish-spears with movable heads exhibits much ingenuity, and the use of no small reasoning power in adapting means to an end.”

We are indeed too apt to apply our own artificial standards as the sole test of intellectual vigour; whereas it is probable that in the amount of acquired knowledge and acuteness of reasoning many savage races surpass the majority of the illiterate peasantry in the most civilised countries of Europe. Mr. Wallace, in viewing the subject in one special light, remarks: “The brain of the lowest savages, and, as far as we yet know, of the prehistoric races, is little inferior in size to that of the higher types of man, and is immensely superior to that of the higher animals; while it is universally admitted that quantity of brain is one of the most important, and probably the most essential of the elements which determine mental power. Yet the mental requirements of savages, and the faculties actually exercised by them, are very little above those of animals. The higher feelings of pure morality and refined emotion, and the power of abstract reasoning and ideal conception, are useless to them; are rarely, if ever, manifested; and have no important relations to their habits, wants, desires, and well-being. They possess a mental organ beyond their needs.”[162]

Here, however, it may be well to guard against the confusion of two very distinct elements. The higher feelings of pure morality and refined emotion are not manifestations of intellectual vigour in the same sense as is the power of abstract reasoning and ideal conception. It is not rare to find an English or Scottish peasant with little intellectual culture or capacity for abstract reasoning, but with an acutely instinctive moral sense. On the other hand, among the criminal class, it is by no means rare to find examples of wonderfully vigorous intellectual power applied to the planning and accomplishing of schemes which involve as much foresight and skill as many a triumph of diplomacy; but which at the same time seem to be nearly incompatible with any moral sense. Moreover, it is needless to say that intellectual vigour and high moral principle are by no means invariable concomitants in any class of society; nor can they be traced to a common source. Mr. Wallace recognises that “a superior intelligence has guided the development of man in a definite direction, and for a special purpose”; and such guidance involves much more than the mere evolution of a higher animal organisation. But, appreciating as he does the difficulties involved in any acceptance of a theory of evolution which assumes man to be the mere latest outgrowth of a development from lower forms of animal life, Mr. Wallace points out that “natural selection could only have endowed savage man with a brain a little superior to that of an ape, whereas he actually possesses one very little inferior to that of a philosopher.”

Yet neither Mr. Wallace, nor Professor Huxley when controverting this argument, withholds a due recognition of the activity of the intellect of the savage. No one indeed can have much intercourse with savage races wholly dependent on their own resources without recognising that, within a certain range, their faculties are kept in constant activity. The savage hunter has not merely an intimate familiarity with all the capabilities and resources of many regions traversed by him in pursuit of his game; his geographical information includes much useful knowledge of the topography of ranges of country which he has never visited. I found, on one occasion, when exploring the Nepigon River, on Lake Superior, that my Chippeway guides, though fully 500 miles from their own country, and visiting the region for the first time, were nevertheless on the lookout for a metamorphic rock underlying the syenite which abounds there; and they made their way by well-recognised land-marks to this favourite “pipestone rock.” While moreover the Indian, like other savages, is devoid of much of what we style “useful knowledge,” but which would be very useless to him, he is fully informed on many subjects embraced within the range of the natural sciences; and has a very practical knowledge of meteorology, zoology, botany, and much else which constitutes useful knowledge to him. He is familiar with the habits of animals, and the medicinal virtues of many plants; will find his way through the forest by noting the special side of the trunks on which certain lichens grow; and follow the tracks of his game, or discover the nests of birds, by indications which would escape the most observant naturalist. The Australian savage, stimulated apparently to an unwonted ingenuity by the privations of an arid climate, is the inventor of two wonderfully ingenious implements, the _wommera_ or throwing stick, and the _bomerang_, which, when employed by the native expert, accomplish feats entirely beyond any efforts of European skill. Moreover, as Professor Huxley remarks, he “can make excellent baskets and nets, and neatly fitted and beautifully balanced spears; he learns to use these so as to be able to transfix a quartern loaf at sixty yards; and very often, as in the case of the American Indians, the language of a savage exhibits complexities which a well-trained European finds it difficult to master.” Again he goes on to say: “Consider that every time a savage tracks his game he employs a minuteness of observation, and an accuracy of inductive and deductive reasoning which, applied to other matters, would assure some reputation to a man of science, and I think we need ask no further why he possesses such a fair supply of brains. In complexity and difficulty, I should say that the intellectual labour of a good hunter or warrior considerably exceeds that of an ordinary Englishman.” Hence Professor Huxley is not prepared to admit that the American or Australian savage possesses in his brain a mental organ which he fails to turn to full account. But without entering on the questions of evolution and natural selection in all their comprehensive bearings, it is still apparent that the brain of the savage is an instrument of great capacity, employed within narrow limits.

In estimating the comparative size of the brain, it is seen to be necessary to discriminate between individuals or races of small stature and cases of true microcephaly. On the other hand, it is not to be overlooked that examples of idiocy are not rare where the head is of a fair average size, and where the mental imbecility is regarded as congenital. But in this as in other researches of the physiologist, he is limited in his observations mainly to the chance opportunities which offer for study; and not unfrequently the prejudices of affection arrest the hand of the student, and prevent a _post-mortem_ examination in cases where science has much to hope for from freedom of investigation. Hence the data thus far accumulated in evidence of the actual structure, size, and weight, of the human brain fall far short of what is requisite for a solution of many questions in reference to the relations between cerebration and mental activity. From time to time men of science have sought by example, as well as by precept, to lessen such impediments to scientific research. Dr. Dalton left instructions for a _post-mortem_ examination in order to test the peculiarity of his vision, which he had assumed to be due to a colouring of the vitreous humour; Jeremy Bentham bequeathed his body to his friend Dr. Southwood Smith, for the purposes of anatomical science; and the will of Harriet Martineau contained this provision: “It is my desire, from an interest in the progress of scientific investigation, that my skull should be given to Henry George Atkinson, of Upper Gloucester Place, London, and also my brain, if my death should take place within such distance of his then present abode as to enable him to have it for purposes of scientific investigation.” The will is dated March 10, 1864; but by a codicil, dated October 5, 1871, this direction is revoked, with the explanation which follows in these words: “I wish to leave it on record that this alteration in my testamentary directions is not caused by any change of opinion as to the importance of scientific observation on such subjects, but is made in consequence merely of a change of circumstances in my individual case.” The natural repugnance of surviving relatives to any mutilation of the body must always tend to throw impediments in the way of such researches; though it may be anticipated that, with the increasing diffusion of knowledge, such obstacles to its pursuit will be diminished. Thus far, however, notwithstanding the persevering labours of Welcker, Bergmann, Parchappe, Broca, Boyd, Skae, Owen, Thurnam, and other physiologists, their observations have been necessarily limited almost exclusively to certain exceptional sources of evidence, embracing to a large extent only the pauper and the insane classes; and in the case of the latter especially, the functional disorder or chronic disease of the organ under consideration renders it peculiarly desirable that such results should be brought, as far as possible, into comparison with a corresponding number of observations on healthy brains of a class fairly representing the social and intellectual status of a civilised community.

The average brain-weight of the human adult, as determined by a numerous series of observations, ranges for man from 40 oz. to 52½ oz., and for woman from 35 oz. to 47½ oz. But some indications among ancient crania tend to suggest a doubt as to whether this difference in cerebral capacity was a uniformly marked sexual distinction among early races; due allowance being made for difference in stature. Dr. Thurnam made the race of the British Long Barrows a special subject of study; and Dr. Rolleston followed up his researches with valuable results. Amongst other points, he noted that the males appear to have averaged 5 ft. 6 in., and the females 4 ft. 10 in. in height. But while the difference of stature between the male and the female exceeds what is observable in most modern races, the variation in the size and internal capacity of their skulls appears to be less than among civilised races. The like characteristics are noticeable in the larger race of Europe’s Palæolithic era. Nothing is more striking in the discovery of those ancient remains of European man than the remarkable development of the skulls and the good brain capacity of the race of the palæotechnic dawn, where man is proved, by his works of art and all the traces of his hearth and home, to have been still a rude hunter and cave-dweller. The Canstadt type of skull is assumed to be that of the earliest European race of which traces have thus far been discovered; and it is unquestionably markedly inferior in development to that of the artistic Troglodytes of the French Reindeer period. Yet remarkable examples of atavism, as in the skull of St. Mansuy, the missionary bishop of Toul, in Lorraine, in the fourth century, and in that of Robert the Bruce, show a reversion to this early type, in accompaniment with exceptional intellectual capacity. The Neanderthal skull, an extreme example of the primitive type, is pronounced by Professor Schaaffhausen to be the most brutal of all human skulls; though this impression is mainly due to the abnormal development of the superciliary ridges, in which it undoubtedly approximates to the chimpanzee or the gorilla. But it has an estimated capacity of 75 cubic inches, and a corresponding cerebral development in no degree incompatible with the idea that the remains recovered from the Neanderthal cave may be those of a skilled hunter; and one apt in the ingenious arts of the primitive tool-maker.

Whatever other changes, therefore, may have affected the brain as the organ of human thought and reasoning, it does not thus far appear that the average mass of brain has greatly increased since the advent of European man. Important exceptions have indeed been noted. Professor Broca’s observations on the cerebral capacity of the Parisian population at different periods, based on nearly 400 skulls derived from vaults and cemeteries of dates from the eleventh or twelfth to the nineteenth century, appear to him to show a progressive cerebral development in that centre of European civilisation.[163] But though the assumption is not inconsistent with other results of civilisation, and is the necessary corollary of the postulate that intellectual activity tends to development of brain, the fact that the crania presented a still greater diversity in type than in size reminds us of the intermixture of races on the banks of the Seine, and the consequent necessity for much more extended observations before so important a deduction can be received as an established truth.

Taking the average brain-weight of the human adult as already stated, all male brains falling much below 40 oz. or 1130 grammes, and female brains below 35 oz. or 990 grammes, may be classed as _microcephalous_; and all above the maxima of the medium male and female brain, viz. 52½ oz. or 1480 grammes, and 47½ oz. or 1345 grammes, may be ranked as _megalocephalous_, or great brains.

Professor Welcker, who devoted special attention to the whole subject under review, assumes another and simpler test when he says that skulls of more than 540 to 550 millimetres, or 21.26 to 21.65 inches in circumference—the weight of brain belonging to which is 1490 to 1560 grammes (52.5-55 oz. av.)—are to be regarded as exceptionally large. But while an excess of horizontal circumference may be accepted as indicating good cerebral capacity, it must not be overlooked that the adoption of it as the key to any definite or even approximate brain-weight ignores the important elements of variation involved in the difference between acrocephalic and platycephalic head-forms. The volume of brain in Scott, and probably in Shakespeare, appears to have depended more on its elevation than its horizontal expansion. The same was also the case with Byron. The intermastoid arch, measured across the vertex of the skull from the tip of one mastoid process to the other, furnishes an accurate gauge of this development. Of thirteen selected male English skulls in Dr. Davis’s collection, the mean of this measurement is 15.1; and of thirty-nine male and female English skulls, it is only 14.4. Of the whole number of eighty-one English skulls described in the _Thesaurus Craniorum_, three exceptionally large ones are: No. 123, that of an ancient British chief, of fully 6 ft. 2 in. in stature, from the Grimsthorpe Barrow, Yorkshire; No. 905, a calvarium of great magnitude, very brachycephalic, and with the elevation across the middle of the parietals apparently exaggerated by compression in infancy, from Hythe, Kent; and No. 1029, another male skull, remarkable alike for its size and weight, and with a peculiarity of conformation ascribed by Dr. Davis to synostosis of the coronal suture. The intermastoid arch in those exceptionally large skulls measures respectively 16.0, 16.2, and 16.9, whereas the same measurement derived from the cast of Scott’s head taken after death, yields the extraordinary dimensions of 19 inches. This last measurement is over the hairy scalp. But after making ample allowance for this, the vertical measurement of the skull and consequently of the brain is remarkable.

Full value has been assigned at all periods to the well-developed forehead. It is characteristic of man. The physiognomist and the phrenologist have each given significance to it in their respective systems; and it has received no less prominent recognition from the poets. A fully developed forehead is assumed as distinctive of the male skull. But Juliet, in _The Two Gentlemen of Verona_, when depreciating her rival, exclaims, “Ay, but her forehead’s low”; and the jealous Queen of Egypt, in _Antony and Cleopatra_, is told of Octavia that “her forehead is as low as she would wish it.” “The fair large front” of Milton’s perfect man is the external index of an ample cerebrum: the organ to which the seat of consciousness, intelligence, and will is assigned. It is therefore consistent with this that a low, retreating forehead is popularly assumed to be the characteristic index of the savage, and of the unintellectual among civilised races. But the cerebral characteristics of both ancient and modern civilised races have still to be studied in detail; and the influence of race and sex on the form of the head and the mass and weight of the brain, involves some curious questions in relation to the oldest illustrations of the physical characteristics of man, and to the effect of civilisation on the relative development of the sexes.

Early observations led Dr. Pruner-Bey and other ethnologists of France to recognise in certain ancient Gaulish skulls of a brachycephalic type the evidences of a primitive race, assumed to represent the inhabitants of France and of Central Europe during its Reindeer period, and which appeared to be assigned with reasonable probability to a Mongol origin. But in the Cro-Magnon cavern, and in other caves more recently explored, the remains of a race of men have been brought to light markedly dolichocephalic, and no less striking in cranial capacity. Dr. Broca speaks of these ancient cave-dwellers of the valley of the Vézère as characterised by “sure signs of a powerful cerebral organisation. The skulls are large. Their diameters, their curves, their capacity, attain, and even surpass, our medium skulls of the present day. The forehead is wide, by no means receding, but describing a fine curve. The amplitude of the frontal tuberosities denotes a large development of the anterior cerebral lobes, which are the seat of the most noble intellectual faculties.”

This primitive race of hunters, marked by such exceptional characteristics, belonged to the remote Reindeer period of Western Europe, and was contemporary with the mammoth, the tichorine rhinoceros, and the fossil horse, as well as with the cave-lion, the cave-bear, and other long-extinct carnivora of Europe. The remarkable evidence of their intellectual capacity has already been reviewed, in considering the manifestations of the artistic faculty among primitive races. Their weapons and implements, including carved maces or official batons, as they are assumed to be, contribute additional evidence of skill and latent capacity among a primitive race of hunters and cave-dwellers. Dr. Broca, after a consideration of the merits of their ingenious arts, says: “They had advanced to the very threshold of civilisation”; and Dr. Pruner-Bey thus comments on their characteristics: “If we consider that its three individuals had a cranial capacity much superior to the average at the present day; that one of them was a female, and that female crania are generally below the average of _male_ crania in size; and that nevertheless the cranial capacity of the Cro-Magnon woman surpasses the average capacity of male skulls of to-day, we are led to regard the great size of the brain as one of the more remarkable characters of the Cro-Magnon race. This cerebral volume seems to me even to exceed that with which at the present day a stature equal to that of our cave-folks would be associated; whilst the skulls from the Belgium caves are small, not only absolutely, but even relatively in the rather small stature of the inhabitants of those caves.”

The Canstadt head is undoubtedly an unintellectual type suggestive of an inferior, though not necessarily an older savage race; for the evidence of climate, contemporary fauna, and other indices of the environments of the Cro-Magnon cave-dwellers, all point to an early Post-Glacial era. Dr. Isaac Taylor, in his _Origin of the Aryans_, assuming the priority of the Canstadt man, speaks of him as “this primitive savage, the earliest inhabitant of Europe.” The forehead in this type is low and receding, and the cerebral capacity generally correspondingly inferior. The relative superposition in some discoveries of ancient human remains, as in the alluvium and gravels of a former bed of the Seine, at Grenelle, lends confirmation to the idea that in this poorly-developed cranial type we recover the physical characteristics of the earliest type of the European savage thus far brought to light. But no disclosure of regular sepulture, or of implements or carvings assignable to him, have hitherto furnished the means of determining his condition or mode of life.

The disclosures of the rock-shelters in the valley of the Vézère are, on the contrary, replete with interest, from the evidence they furnish of a race of savage hunters, in whom ingenious skill and great artistic aptitude gave evidence of latent intellectual capacity of a high order. The remarkable size of crania accompanying those examples of primitive art seemingly pertaining to the Troglodytes of the Mammoth and Reindeer periods of Central Europe, is the more significant from its bearing on the evidence of progressive cerebral development adduced by Dr. Broca from skulls recovered from ancient and modern cemeteries of Paris. It appears, indeed, to conflict with any theory of a progressive development from the Troglodyte of the Post-Glacial age to the civilised Frenchman of modern times. Professor Boyd Dawkins has accordingly been at some pains in his _Cave Hunting_ to show that the conclusions formed by previous observers as to the epoch of their burial are not supported by the facts of the case; and he sums up his review of the whole evidence by expressing a conviction that he “should feel inclined to assign the interments to the Neolithic age, in which cave-burial was so common. The facts,” he adds, “do not warrant the human skeletons being taken as proving the physique of the palæolithic hunters of the Dordogne, or as a basis for an inquiry into the ethnology of the palæolithic races. Professor Boyd Dawkins also pronounces the same doubts in reference to the equally characteristic male skeleton found in a cave at Mentone, and to others obtained in the Lombrive and other caves. It is not to be overlooked that the possibility of the intrusion of human remains into earlier strata constitutes an important element suggesting caution in reasoning from such evidence. For the remains of man differ from those of other animals found in such series of deposits as mark a succession of periods, in so far as they pertain to the only animal habitually given to the practice of interment. Human skeletons found under such circumstances may have been artificially intruded long subsequent to the accumulation of the breccia in which they lay. Happily, however, any doubts as to the contemporaneity of the human remains with the other cave relics has been removed by the discovery of skeletons, similar in type, in other caverns in the same valley—and especially in that of Laugerie Basse,—in positions which seem to leave no room for questioning their being of the same age as the works of art found along with them.

Other examples of the ancient man of Europe show him in like manner endowed with a cerebral development in advance of the rudest races of modern times. The skull found by Dr. Schmerling in the Engis cave, near Liège, along with remains of six or seven human skeletons, was embedded in the same matrix with bones of the fossil elephant, rhinoceros, hyæna, and other extinct quadrupeds. It is a fairly proportioned, well-developed dolichocephalic skull; and, like others of the ancient human skulls of different types thus far found, has signally disappointed the expectations of those who count upon invariably finding a lower type the older the formation in which it occurs. “Assuredly,” says Professor Huxley, “there is no mark of degradation about any part of its structure. It is, in fact, a fair average human skull, which might have belonged to a philosopher, or might have contained the thoughtless brain of a savage.” Even the famous Neanderthal skull, of uncertain geological antiquity, but pronounced to be “the most brutal of all human skulls,” acquires its exceptional character, as already noted, chiefly from the abnormal development of the superciliary region.

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It is a universally accepted fact that the size of the male head and the weight of the brain are greater than those of the female. The average weight of the male brain is found to exceed that of the female by about 10 per cent; or, as it is stated by Professor Welcker, the brain-weight of man is to that of woman as 100 to 90. But the difference of stature between the two sexes has to be taken into account. The average, based on various series of observations to determine the mean stature for man and for woman, shows the latter to be about 8 per cent less than the former; or, as Dr. Thurnam has stated it more precisely:

RATIO OF STATURE AND BRAIN-WEIGHT IN THE TWO SEXES

MALE. FEMALE.
Stature 100 92.0
Weight of brain 100 90.3

Here again, however, it becomes important to take into consideration other elements of difference besides weight; for, as Tennyson insists, “Woman is not undevelopt man, but diverse.” The results of Wagner’s observations on the superficial measurements of the convolutions of the brain point to the conclusion that in the female the lesser brain-weight may be compensated by a larger superficies. Ranked in the order of their relative weights in grammes, six average brains of men and women were found to stand thus:—

1. Male (_a_) 1340
2. Male (_b_) 1330
3. Male (_c_) 1273
4. Female (_d_) 1254
5. Female (_e_) 1223
6. Female (_f_) 1185

But the same brains, when tested by the degrees of convolution of the frontal lobe, measured in squares of sixteen square millimetres, irrespective of the question of relative size, ranked as follows, advancing the female (_d_) from the fourth to the first place, and reducing the male (_c_) from the third to the sixth place:—

1. Female (_d_) 2498
2. Male (_a_) 2451
3. Male (_b_) 2309
4. Female (_f_) 2300
5. Female (_e_) 2272
6. Male (_c_) 2117

But, as already indicated, some modern disclosures tend to raise the question whether the difference between the sexes, in so far as relative volume of brain is concerned, has not been increased as a result of civilisation. The disparity in size between the Cro-Magnon male and female skeletons is quite as great as that of modern times, but the capacity of the female skull is relatively good.

Other observations, such as those of Professor Rolleston “On the People of the Long Barrow Period,” seem to indicate a nearer approximation in actual cranial capacity of the two sexes in prehistoric times than among modern civilised races. On the assumption that intellectual activity tends to permanent development of brain, it is consistent with the conditions of savage life that it should bring the mental energies of both sexes into nearly equal play. They have equally to encounter the struggle for existence, and have their faculties stimulated in a corresponding degree. As nations rise above the purely savage condition of the hunter stage, this relative co-operation of the sexes is subjected to great variations. The laws of Solon with reference to the right of sale of a daughter or sister, and the penalties for the violation of a free woman, show the position of the weaker sex among the Greeks at that early stage to have been a degrading one. But the change was great at a later stage; and much of our higher civilisation is traceable to the early establishment of the European woman’s rights, which Christianity subsequently tended to enlarge. The position of woman among the ancient Britons appears to have been one of perfect equality with man. Among the Arabians and other Mohammedan nations, including the modern Turks, the opposite is the case; and the whole tendency of the creed of the Koran, and the social life among Mohammedan nations, must be towards the intellectual atrophy of woman. Hence it is consistent with the diverse conditions of life that, in so far as cerebral development is the result of mental activity, a much closer approximation is to be looked for in the mass and weight of brain in the two sexes among savage races, than among nations where woman systematically occupies a condition of servile degradation, or of passive inertness.

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Some interesting results of the actual brain-weights of Negroes and other typical representatives of inferior savage races have been published, including examples of both sexes; and although the observations are as yet too few for the deduction of any absolute or very comprehensive conclusions, they furnish a valuable contribution towards this department of ethnical comparison. In 1865, Dr. Peacock published the results of observations on the brains of four Negroes and two Negresses; and to those he subsequently added a seventh example.[164] Others are included in the following table. But I have excluded some extremes of variation, such as the two given by Mascagni, one of which weighed 1458 grammes, or 51.5 oz. av., and the other only 738 grammes, or 26.1 oz. av. In addition to such actual brain-weights, Morton, Tiedemann, Davis, Wyman, and others, have gauged the skulls of Negroes, American Indians, Mincopies, Tasmanians, Australians, and other savage races, as well as those of many civilised and semi-civilised nations, and thereby contributed valuable data towards determining their relative cranial capacity. In his _Crania Ægyptiaca_, Dr. Morton, when discussing the traces of a Negro element in the ancient Egyptian population, says: “I have in my possession seventy-nine crania of Negroes born in Africa, for which I am indebted to Drs. Goheen and M’Dowell, lately attached to the medical department of the colony of Liberia, in Western Africa; and especially to Don Jose Rodriguez Cisneros, M.D., of Havana, in the island of Cuba. Of the whole number, fifty-eight are adult, or sixteen years of age and upwards, and give eighty-five cubic inches for the average size of the brain. The largest head measures ninety-nine cubic inches; the smallest but sixty-five. The latter, which is that of a middle-aged woman, is the smallest adult head that has hitherto come under my notice.”[165]

TABLE I

NEGRO BRAIN-WEIGHT