Eye of Young Kalmuk GirlFIG.18.—Eye of a young Kalmuk girl of Astrakhan.Example of Mongoloid eye(from nature).
FIG.18.—Eye of a young Kalmuk girl of Astrakhan.Example of Mongoloid eye(from nature).
Sometimes this puffiness only extends to the outer part of the eyelid; we have thus a variety of the Mongolian eye, with a palpebral triangular opening, very frequent among the eastern Finns (Fig.106) and the Turco-Tatar populations.
Welsh Type, MontgomeryshireFIG.19.—Welsh type of Montgomeryshire.Eyes and hair dark.(Photo. and particulars, Beddoe.)
FIG.19.—Welsh type of Montgomeryshire.Eyes and hair dark.(Photo. and particulars, Beddoe.)
Thenose, by the variety and the fixity of its forms, presents one of the best characters for distinguishing races. We can express by means of the nasal index of Broca its width (measured by just touching the alæ of the nose) in relation to its length (from the root to the sub-nasal spine) supposed = 100. This index varies in the proportion of one to three(from 40 to 120), according to race. Among the platyrhinians, the breadth of the nose exceeds 85 (Fig.14); among the leptorhinians, this breadth is less than 70 (Fig.16); lastly, among the mesorhinians, it oscillates between 70 and 85, according to the nomenclature of R. Collignon.[75]I give inAppendix III. a table of the nasal indices of the principal populations; I have only introduced into it series ofmore than ten individuals, whose measurements have been taken according to the Broca-Collignon method, explained above.[76]
Besides the general form of the nose given by the nasal index, there remain a host of descriptive characters which may be observed in this organ. It may be more or less flattened (examples: Negroes, Melanesians, Mongolians), or more or less prominent (Europeans, Jews, Arabs). Its profile may be: (1) straight and sometimes sinuous (examples: Turco-Tatars, Europeans, Fig.19); (2) concave (certain Finns, Bushmen, Lapps, Australians, Fig.15); (3) convex and sometimes arched (American Indians, Semites, Fig.21). Each of these forms may be in combination with a fine, thick, or medium tip, and with a plane of the nostrils directed upwards, downwards, or horizontally. A. Bertillon[77]admits at least fifteen varieties of the forms of the nose. In the majority of cases concave noses have the extremity thick, and the plane of the nostrils directed upward (Figs.9,14, and15); convex noses, on the contrary, have most frequently the tip fine, and the plane of the nostrils directed downward (Figs.21,102,103, and134). But there are also convex noses with very thick tips, for instance, among the Jews and the Iranians of the Assyroid type (Fig.22), or again, among the Papuans and the Melanesians (Fig.53), as well as concave noses with fine tips, for instance, among certain European races (Figs.97,104, and105). Broad noses are most frequently flattened (Figs.14,15, and24), but the flattening may also extend to narrow noses, as for example among the Mongols (Fig.20). The sunken, very depressed root of the nose is almost always associated with a considerable prominence on the supraciliaryarches: examples, Australians, Fuegians, etc. (Figs.14,15, and48).
Kalmuk of AstrakhanFIG.20.—Kalmuk of Astrakhan.Example of convex and flattened nose.(Phot. S. Sommier.)
FIG.20.—Kalmuk of Astrakhan.Example of convex and flattened nose.(Phot. S. Sommier.)
In a general way, as may be seen from the table, the leptorhinians, who have for the most part the convex and straight noses, with fine, straight, or turned-down tips, are met with almost exclusively among Europeans, Eurasians, Armenians,Caucasians, and Eurafricans (Arabo-Berbers), as well as among the inhabitants of anterior Asia. The mesorhinians, among whom the form of the profile of the nose varies much, include different populations of India, some American, Turco-Tatar, and Mongol peoples. And lastly, the platyrhinians, having most frequently the profile convex and the tip turned up, comprise the whole of the black populations of Africa, Oceania, and India.
Jew of AlgiersFIG.21.—Jew of Algiers.Example of convex and prominent nose.(Phot. Coll. Mus. Hist. Nat., Paris.)
FIG.21.—Jew of Algiers.Example of convex and prominent nose.(Phot. Coll. Mus. Hist. Nat., Paris.)
At birth and during early infancy the nose is most frequently concave, with the tip turned up (Fig.130); it only becomes straight or convex in the adult; in old age it has a tendencyto become convex with the tip turned down (Bertillon, Hoyer). In the dead body it always takes the arched form. According to Broca and Houzé, the nasal index has a tendency to get lower—that is to say, the nose becomes relatively thinner as the individual advances in age; according to Hoyer,[78]the contrary takes place.
Jew of AlgiersFIG.22.—Persian Hadjemi.Example of Assyroid nose.(Author’s Phot. Coll.)
FIG.22.—Persian Hadjemi.Example of Assyroid nose.(Author’s Phot. Coll.)
The ears present few characteristic traits for distinguishing races,[79]but the same cannot be said of the lips. They are thin in the so-called white races and among Mongols; very thick and protruding among the Negroes; somewhat thick among Malays, Melanesians, etc. Their form contributes much towards hiding or accentuating dental or alveolar prognathism.
Skeleton of the Trunk and Limbs.—The parts of the skeleton other than the head furnish but few materials for characterisingraces. We have already seen (p.14) that the differences of curvature in thevertebral columnaccording to race may be explained by the mode of life. As to the other peculiarities of the spine,—spinous processes split in the cervical vertebræ,[80]narrow sacrum, etc.,—all that can be said about them is that they are more frequent among Negroes, and perhaps among Melanesians, than among Whites.
Thepelvishas more importance on account of its function from the obstetrical point of view, and of its influence on the general form of the body. Unfortunately this part of the skeleton has only been studied in very inadequate series among a dozen populations. Subjoined is given:—1st, the table ofpelvic index—that is to say, the centesimal relation between the maximum breadth of the pelvis (between the iliac crests) and its height (from the top of the iliac crest to the lowest point of the ischion), taking for our unit sometimes the first of these measurements following Turner, sometimes the second following Broca; 2nd, the table of the index of the inlet (pelvic or brim indexof English authors)—that is to say, the relation of the antero-posterior diameter of this aperture (from the middle of the promontory of the sacrum to the pubic symphysis) to its maximum transverse diameter, which, let us suppose, = 100.[81]It will be remarked that the tables, formed of series of five subjects at least, are given in separate parts for men and for women, as the sexual differences are very appreciable in the pelvis of all races. In a general way the pelvis is broader and less high, its slope more pronounced, in woman than in man. The iliac fossa are wider in the former than in the latter; thesuperior inletorbrimis elliptical or reniform in woman, in the formof a playing-card heart in man, etc. But, as may be seen by our table, if these differences are very appreciable in certain races, notably among Whites and Negroes, they become less and less among Melanesians, among whom the pelves of the two sexes approximate nearly to the masculine type.
Has the form of the pelvis, and especially that of the inlet, any relation to the form of the head of the fœtus and of the child? Exact data for solving this question are wanting. However, comparing from our tables the index of the superior inlet and that of the cephalic index, it may be observed that, in a general way, pelves with a large aperture are met with in brachycephalic races, and pelves with a narrow aperture in dolichocephalic races. But there are numerous exceptions: I note at least four (English, Russian, Swedish mesocephal and Malay women) in the meagre list of 12 series of women that, with much difficulty, I have been able to draw up.
The form of theshoulder-bladevaries little with race. Thescapular index—that is to say, the centesimal relation between the breadth of the shoulder-blade and its length (measured on the vertebral edge and taken as the unit of comparison)—oscillates between 64.9 (Australians) and 70.2 (Andamanese). In a list of 14 series of from 10 to 462 shoulder-blades that I have drawn up from the works of Broca, Livon, Turner, Topinard, Garson, Martin, Hyades, Sarasin, Hamy, Koganei, and my own measurements, the populations are arranged as follows: index from 64.9 to 66.6, Australians, Europeans, Fuegians, Bushmen, Ainus, Peruvians, Polynesians; indices from 67.2 to 70.2, Japanese, Veddahs, Hindu-Sikhs, Malays, Negroes, Melanesians, Andamanese. This classification suffices to show that the greater or less breadth of the shoulder-blade has almost no value as a seriate character or as a character of race. It is the same with thesub-spinal index, which it has been proposed to add to the foregoing in order to judge of the form of the shoulder-blade.[82]
As to the skeleton of the limbs, here is a summary of what can be said about it from the point of view which specially concerns us now. In thethoracic limbthehumeruspresents an interesting peculiarity: the perforations of theolecranon cavity(which receives the extremity of the ulna) are very frequent in prehistoric bones in Europe (10 to 27 times in 100), as well as in America (31 times).[84]
This perforation is met with more often among men than women, perhaps because it is more especially connected with the extent and frequent repetition of the movements of flexion and extension. Here is its growing frequency in the races from a list which I have drawn up with series varying from 20 to 249 humeri: white population of the United States (3.8 times in a hundred), French, Fuegians, Ainus, Basques, Melanesians, Japanese, Negroes, Polynesians, Mongolians, and American Indians (36.2 times in a hundred). Thetorsion of the humerus—that is to say, the degree of rotation of the lower part of this bone in relation to its upper part, is a character of a certain seriate value; but it is of no use in the differentiation of races. Besides, the degree of torsion varies too much in the same race: it is greater in woman than in man, in short than in long humeri (Manouvrier, Martin, etc.). This torsion is measured by theangle of torsion, which is taken either according to Broca’s method or Gegenbaur’s. This is how the different peoples are arranged according to the decreasing figures of this angle (series of 10 humeri): according to Broca’s system:—Melanesians (angle of 141°), Guanches, Arabs or at least Kabyles, Polynesians, Negroes, Peruvians, Californians, Europeans, French (164°); according to Gegenbaur’s system:—Ainus (149.5°), Fuegians, Veddahs, Japanese, Swiss, Germans(168°). Until further discoveries are made, a single fact becomes prominent from the examination of this character—that is, that the torsion appears to be greater in white races than in black and yellow. In the ulna Collignon has noted a special incurvation in certain prehistoric bones.
Skull, Malar Bone, FemurFIG.23.—A, Skull with Inca Bone,b;B, Malar Bone divided in two (a,os Japonicum);C, superior part of femur with third trochanter (3), and the hypo-trochanteric fossa (x);1 and 2, normal trochanters.
FIG.23.—A, Skull with Inca Bone,b;B, Malar Bone divided in two (a,os Japonicum);C, superior part of femur with third trochanter (3), and the hypo-trochanteric fossa (x);1 and 2, normal trochanters.
In thefemurone peculiarity has especially attracted the attention of anthropologists in recent times; it is the more or less frequent presence of thethird trochanter(Fig.23, C 3), or tuberosity situated between the great (ibid., 1) and the lesser (ibid., 2) trochanter on the offshoot from thelinea asperawhichfurnishes a point of attachment to the lower part of thegluteus maximus. This projection, pointed out and studied for the first time by Houzé,[85]appears in infancy as a special centre of ossification analogous to those of the other diaphyses (Török, Deniker, Dixon), and so does not seem to depend on the greater or less development of thegluteus maximus(Bertaux).[86]The third trochanter is almost always accompanied by ahypotrochanteric fossa(Fig.23, C).
Here is the frequency with which the third trochanter occurs according to a list which I have compiled:—
Two points will be observed in this table, the rarity of the third trochanter among Negroes, and its excessive frequency among the Fuegians. The women of the latter have also the hypochanteric fossa 80 times in a 100 (out of 76 femurs examined); it almost forms then, like the third trochanter, a character of race.
In thetibiaattention has been called toplatycnemia—that is to say, the transversal flattening in the upper third of the diaphysis of the bone, so that its posterior side becomes transformed into a border. It has been supposed that this form is a reversion towards the simian type, but Manouvrier[87]has shown that platycnemia never attains in the anthropoid apes the degree which it presents in the human race, where it is due especially to the development of thetibialis posticusmuscle which plays a great part in the maintenance of the upright position, and in the movements of walking and running. The degree of platycnemia may thus vary according to the more or less sedentary or wandering habits of the different populations.
The retroversion of the head of the tibia—that is to say, the slope of the articular surface of it behind—pointed out and described for the first time by Collignon in prehistoric tibias, is also not a simian character. According to Manouvrier,[88]it is often met with among Parisians in a degree superior to that exhibited by anthropoid apes. This retroversion, generally associated with platycnemia, is connected with the half-bending attitude of the lower limb in the manner of walking which is called thebending gait, common among peasants, and especially mountaineers. The retroversion is more marked in the tibia of the new-born child than in that of the adult, and this appears to have a connection with the permanent bending of the knee during intra-uterine life.
The length of the bones of the pelvic and thoracic limbsvaries according to race, but it is difficult to establish the degree of these variations, owing to the small number of observations made. Besides, we can more profitably substitute for measurements of limbs on the skeleton those of the living subject; in the latter case we can at least relate all the measurements to the true height of the subject, whilst the height is never exactly known from the skeleton.
However, the measurements of the long bones have theirimportance, for they permit us toreconstituteapproximately, as we have already seen (p.33),the heightof subjects of which we have only the bones, as is the case of all populations that have preceded us.
It is for this reason that I give the following figures derived from nine series of from five to seventy-two skeletons. The length of the humerus represents from 19.5 (Polynesians) to 20.7 per cent. (Europeans) of the height of the skeleton; that of the radius from 14.3 (Europeans) to 15.7 (Negroes); that of the femur from 26.9 (South Americans) to 27.9 (New Caledonians); lastly, the length of the tibia represents from 21.5 (Esthonians) to 23.8 per cent. (New Caledonians) of the height of the skeleton. Thus the differences are insignificant, and the variations between race and race do not extend beyond the limits of a unit and a half for each of the bones.
The length of the radius in relation to the humerus (= 100) exhibits variations a little more appreciable. It is 72.5 among Europeans, 76 among New Caledonians, 79 among Negroes, 79.7 among Veddahs, 80.6 among Fuegians, 81.7 among Andamanese. Let us note that the fore-arm, relatively to the arm, is much longer in the fœtus in the first stages of development and in early infancy than in the adult;[89]it is shortened in proportion to the height as the fœtus and the infant grow.
Proportions of the Body in the Living Subject.—In spite of the quantity of material accumulated, we have not been able up to the present to make any use of the differences which these proportions exhibit according to race. The reason is that these differences are very trifling. In order to understand this proposition better I will give by way of illustration the proportions which we may consider as nearly normal in a European of average stature (1 m. 65, or 5 ft. 5 ins.). Topinard established thus the principal proportions of the European,[90]assuming the height = 100.
The proportions in the different populations of the earth oscillate round these figures without diverging from them more than three units, or five at most. Thus, for example, the proportions of the height of the head vary between 11.4 and 15, according to Rojdestvensky;[91]the proportions of the trunk without the neck from 32.6 to 32.8, according to Topinard, etc.
The length of the thoracic limb scarcely varies more than between 42.6 and 47.6, according to the lists of sixteen and twenty-seven series published by Ivanovsky and Topinard,[92]and according to a third list of twenty-four series that I have drawn up. We can count on the fingers the populations in which the proportion for the hand exceeds the figure 11 with its decimals or sinks below it; it is the same in regard to the foot, of which the figure 15 with its decimals is rarely exceeded or is not reached.[93]The variations of length for the abdominal limb do not extend further than from 45.1 to 49.2 (Topinard), etc.
The thoracic perimeter exceeds half the height in all adult populations of the world, except perhaps some groupsof Georgian Svanes and Jews, or other populations which happen to be in bad hygienic conditions.
Thus proportions of the limbs are not good characters of race. Besides, certain dimensions (length of limbs, of the head) are always dependent on height. Thus individuals and races of high stature have the face and abdominal limb a little more elongated than individuals and races of short stature. On the other hand, individuals and races of short stature have in general the head larger, the trunk shorter, and the thoracic perimeter relatively more considerable than individuals and races of high stature, but the differences are very trifling as a general rule.
Trunk and Limbs of the Living.—To complete our study on the living subject, let us again note some peculiarities. Theneckis ordinarily long and thin among Negroes, Ethiopians (Figs.9and138), and on the contrary short among the majority of the American Indians (Figs.163and169); the shoulders are very broad among the women of the latter (Fig.165), and very narrow among the Chechen and Lesghi women. Usually the long neck is associated with a form of trunk like an inverted pyramid and a high stature, while the short neck surmounts a cylindrical trunk and is associated with a low stature.Ensellure—that is to say, the strongly marked curve of the dorso-lumbo-sacral region—is especially marked among Spanish women whose lumbar incurvation is such, and the movements of the lumbar vertebræ so extensive, that they are able to throw themselves backwards so as even to touch the ground (Duchenne of Boulogne). Ensellure is also more marked among Negroes than among Whites. It must be noted that it may also be merely a consequence of abdominal obesity, pregnancy, orsteatopygia.
By the last-mentioned term is designated excessive projection of the buttocks due to the accumulation of subcutaneous fat (Fig.24); these are physiological fatty tumours proceeding from the hypertrophy of the adipose tissue more or less abundant in these regions among all races, and analogous to the fatty tumours of the cheeks of the orang-utan, which are simplyBichat’s fatty balls existing among men and among the anthropoids,[94]only excessively developed. As in those tumours, the fat of the steatopygous masses does not even disappear after disease which has emaciated the rest of the body. Steatopygia is characteristic of the Bushman race; it is only met with in all its characters (alteration of form on the lateral and anterior sides of the thighs; persistence even in emaciation, etc.) among populations into the composition of which enters the Bushman element: Hottentots (Fig.24), Nama, etc. The cases of steatopygia observed among other Wolof or Somali women, for example, are only the exaggeration of adipose deposit among the muscular fibres, as with Europeans, not of the subcutaneous adipose layer. Steatopygia is especially marked in the Bushman woman, in whom it commences to develop only from the age of puberty; but it exists also, though in a less degree, in the male of that race (Fig.143).
Hottentot Woman, GriqualandFIG.24.—Hottentot woman ofGriqualand (Cape Colony);35 years; height, 4 ft. 8 ins.;cephalic index, 76.4.Example of steatopygia.(Photo. Prince Roland Bonaparte.)
FIG.24.—Hottentot woman ofGriqualand (Cape Colony);35 years; height, 4 ft. 8 ins.;cephalic index, 76.4.Example of steatopygia.(Photo. Prince Roland Bonaparte.)
We cannot enlarge on other exterior characters: on the form of the trunk and of the limbs; on the leg with poorly developed calf, and the foot with the prominent heel which is observed among certain Negroes (but not among all); on the more or less diverging big toe which is remarked among the majority of the peoples of India, Indo-China, and the insular world dependent on Asia, from Sumatra to Japan, etc.
Two words, however, on the subject of the pretended existence of races ofmen with tails. We must relegate to the domain of fable the cases of this kind which are announced from time to time in publications for the popularisation of science so called. The costumes of certain populations have given rise to the fable of men with tails (see frontispiece). Isolated cases of men having as an anomaly a caudal excrescence more or less long, free, or united to the trunk, are known to science, and numbers have been described, but no single serious description has ever been given of populations with tails.[95]Quite recently, again, Lartschneider has demonstrated that the ilio-coccygian and pubio-coccygian muscles in mammifera have lost in man their character of symmetrical and paired skeleton muscles, and are driven back towards the interior of the pelvis as single unpaired muscle plates (fibres of thelevator ani). Primitive man has never had a caudal appendage since he acquired the biped attitude; the disappearance of the tail is even one of the indispensable conditions of that attitude.[96]
The different internal or external organs of man afford also some special characters, though not very numerous, for differentiating race.
Themuscular system, little known outside white races, has, up to the present, not given any important indication on this point. At the very outside, we can say, thanks to the works of Chudzinsky, Le Double, Macalister, Popovsky, Testut, Turner, etc., and the Committee of the Anatomical Society of Great Britain and Ireland, that certain muscular anomalies are more frequent in the Negro than in the White, and that the musclesof the face are less differentiated in the former than in the latter.[97]In the splanchnic system some differences have also been observed between the White and the Negro, notably the excessive volume of the liver, the spleen, the suprarenal-capsules, and, in general, the hypertrophy of all the organs of excretion in the latter compared with the former. The venous system appears also to be more developed in the Negro than in the White. Somewhat notable differences must certainly be observable in the structure and general conformation of the organs of the voice and of speech—tongue, larynx, lungs. But our knowledge on this subject is still very imperfect. Attention has been drawn to the feeble development of the anterior fibres of the stylo-glossal muscle of the tongue, the greater development of the Wrisberg cartilage of the larynx with the muscles stronger in the Negro than in the White,[98]but nothing is known about the larynx of other races.
There is nothing, even to the bony parts of the vocal apparatus, which does not undergo ethnic variations. Thus the larger cornua of thehyoid boneare not attached to the body of it in 75 to 95 per cent. of cases observed among the Indians of America, whilst the same anomaly is met with in only 25 to 35 per cent. of cases among Europeans, and only in 30 per cent. among Negroes, which probably harmonises with the differences in the production of sounds in the language of each of these peoples.[99]
Thegenital organsalso present some differences according to race, but rather in the dimensions of the various parts than in their form. The only peculiarity worth notice is the exaggerated development of the labia minora among the Bushman women, known under the name of “apron.” This peculiarity, which appears from infancy, is met with onlyamong the Bushman race and the people into whose composition enters the Bushman element—Hottentots, Nama, Griqua, etc.[100]
The breasts of women may also present variations of form. Ploss[101]classes them under four heads according to their height, which is inferior, equal, or more or less superior to the diameter of their base; we have thus mammæ like a bowl or the segment of a globe, hemispherical, conical, and pyriform. These forms may be found in combination with a more or less extended and prominent areola, and with a nipple which may be discoidal, hemispherical, digitiform, etc. It is especially among Negresses that we meet with conical and pyriform mammæ, and digitiform nipples, while mammæ shaped like the segment of a sphere predominate among Mongolian and European women of the fair race; women of the south-east of Europe and hither Asia have for the most part hemispherical breasts.
Among the internal organs, thebrain, or better, theencephalon, deserves a little more attention. I have already said with regard to cranial capacity (p.56) that appreciable differences have been observed in the volume of the brain-case according to age, sex, and race. This difference is in harmony with irregularity in the volume and consequently in the weight of the brain. At birth, European boys have 334 grammes of brain on an average, girls 287 grammes. This quantity increases rapidly up to 20 years of age, remains almost stationary between 20 and 40 or 45, then begins to decrease, slowly at first, until 60 years, then more rapidly.
Let me also add that the weight of the encephalon varies enormously according to individuals. Topinard[102]in a series of 519 Europeans, men of the lower and middle classes, found that variations in weight extended from 1025 grammes to 1675grammes. The average weight of the brain among adult Europeans (20 to 60 years) has been fixed by Topinard, from an examination of 11,000 specimens weighed, at 1361 grammes for man, 1290 grammes for woman. It has been asserted that the other races have a lighter brain, but the fact has not been established by a sufficient number of examples. In reality all that can be put against the 11,000 brain-weighings mentioned above concerning the cerebral weights of non-European races, amounts to nothing, or almost nothing. The fullest series that Topinard[103]has succeeded in making, that of Negroes, comprises only 190 brains; that of Annamese, which comes immediately after, contains only 18 brains. And what do the figures of these series teach us? The first series, dealing with Negroes, gives a mean weight not much different from that of Europeans—1316 grammes for adult males of from 20 to 60 years; and the second, dealing with the Annamese, a mean weight of 1341 grammes, almost identical with that of Europeans. For other populations we have only the weight of isolated brains, or of series of three, four, or at most eleven specimens, absolutely insufficient for any conclusions whatever to be drawn, seeing that individual variations are as great in exotic races as among Europeans, to judge by Negroes (1013 to 1587 grammes) and by Annamese (from 1145 to 1450 grammes). Even in the great series of Europeans, surprises await us in comparing the figures. Thus Peacock found an average of 1388 grammes for the English from a series of 28 brains, whilst Boyd finds 1354 grammes from a series of 425 brains. The difference (34 grammes) is greater here than between the brains of Annamese and Europeans, and hardly less than that which we have just found between Negroes and Europeans (45 grammes). For the French the figures are more in agreement. Broca found from the weights of 167 brains an average of 1359 grammes, and Bischoff[104]from 50 brains an average of 1381 grammes; difference, 22 grammes.
Not having at our disposal sufficient data for the weight, let us see if the cranial capacity could not supply them, for we know, since the investigations of Manouvrier,[105]that we have just to multiply by the co-efficient 0.87 the capacity of the cranial cavity to get with reasonable exactitude the weight of the brain which it contained. This is what we learn from the figures of cranial capacity brought together by Topinard,[106]after the necessary corrections, and reduction to cubic measurement by the system of Broca: among Europeans the measurement is 1565 c.c. on an average for men, varying from 1530 c.c. (22 Dutch) to 1601 c.c. (43 Finns). We have in various series the following succession of cranial capacities for the populations of the other parts of the world: the greatest is contained in a series of 26 Eskimo (1583 c.c.), the least that of 36 Australians (1349 c.c.) and of 11 Andamanese (1310 c.c.). Between these two extremes the other populations would be thus arranged in a decreasing order of capacity: 36 Polynesians (1525 c.c.), 18 Javanese (1500 c.c.), 32 Mongols (1504 c.c.), 23 Melanesians (1460 c.c.), 74 Negroes (1441 c.c.), and 17 Dravidians of Southern India (1353 c.c.).
The difference between the highest and lowest of these figures is 255 c.c., a little greater than that which is shown between man and woman in all races. On the other hand, Manouvrier[107]gives the following weights, deduced from cranial capacities: 187 modern Parisians, 1357 grammes; 61 Basques, 1360 grammes; 31 Negroes, 1238 grammes; 23 New Caledonians, 1270 grammes; 110 Polynesians, 1380 grammes; and 50 Bengalis, 1184 grammes; the difference of the two extremes is 196 grammes. Must we then see in these differences the influence of stature and bulk of body, asappears unquestionable in the sexual difference? We are tempted to believe it when we see that the mean weight of the largest brain in Europe has been found among the Scotch (1417 grammes, an average obtained by Reid and Peacock from 157 brains), whose stature is the highest of the human family, and that the mean weight of the Italians, whose average stature is rather small, is only 1308 grammes (from 244 cases weighed by Calori). The Polynesians and the Caucasians,[108]peoples of high stature, also outweigh the Andamanese and the Javanese, of very low stature. However, we see (from weights and cranial capacity) that Negro populations of very high stature, also Australians and New Caledonians of medium stature, have the cerebral weight much smaller than the Eskimo and certain Asiatics of low stature, like the Javanese.
There is here a double influence, that of stature and that of race. We might have introduced a third element—the weight of the body, but it represents too many different things, and may vary according to the degree of stoutness of the individual, the dietary regimen, etc. C. Voit found, when operating on two dogs of nearly equal bulk, that the weight of the brain of the well-fed dog represented 1.1 per cent. of the weight of its body, whilst the brain of the dog which had fasted for twenty-two days represented 1.7 per cent. of the weight of the body.[109]At all events, we cannot deny the influence of the bulk of the active parts of the body on the volume of the brain.[110]But then a new question arises. Isthe increase of the volume of the brain made at the cost of the white substance formed solely of conducting-fibres, or of the grey substance formed principally of cells with their prolongations (neurons), that is to say, of the part which is exclusively affected by the psychic processes? This question still waits its solution. It is not the gross weight of the brain, but really the weight of the cortical layer which should be compared in the different races and subjects, in order to judge of the quantity of substance devoted to the psychic functions in each particular case.[111]Before the very delicate weighings of this kind are made, we have a round-about method of ascertaining the quantity of that substance by the superficial area which it occupies. The cerebral cortex, composed of the grey substance, forms on the surface of the brain sinuous folds calledcerebral convolutions. Now, in brains of equal volume, the greater the surface of the cortex, the more numerous, sinuous, and complicated will be these folds. As the thickness of the grey layer is very much the same in all brains, it is evident that the complexity in the structure of the convolutions corresponds to the increase of the grey substance, and consequently of the psychic force. Now, the little that is known of the cerebralconvolutions in different races, and of various subjects in the same race, appears to conform to this deduction. The brains of idiots, of the weak-minded, present very simple convolutions, almost comparable to those of the anthropoid apes, whose brain is like a simplified diagram of the human brain. On the other hand, distinguished personages, great scholars, orators, men of action, exhibit a complexity, sometimes truly remarkable, ofcertainconvolutions. I say expressly certain convolutions, for all these folds, arranged according to a certain plan, common to all men, have not the same value from the physiological point of view. In the grey layer of certain of them are the centres of motor impulses, and of the general sensibility of the body (for example, those which are arranged around the fissure of Rolando,Fig.25, 2, 2), and only regulate the voluntary movements of the limbs, the trunk and the head; others are connected with different forms of sensibility—visual (Fig.25, 4), auditory (Fig.25, 6), gustatory, olfactory, etc. But there are, between the different motor or sensorial regions (centres of projection) which take nearly a third of the grey substance of the brain, a great many more convolutions the grey substance of which is connected with no special function (white spots in Fig.25). What is their purpose? Basing his opinion on the tardymyelinisation[112]of the nerve-fibres which terminate in it, subsequent to the birth of the individual and to the myelinisation of the fibres of the sensory and motor centres, Flechsig[113]supposes that these convolutions were designed to enable the different cerebral centres to communicate with each other and to render us conscious of this communication; therefore he has named their grey substance “centres of association” (Fig.25, 1, 3, 5). Without the convolutions, the other centres would remain isolated and condemned to a very restricted activity. Now, as the eminent anatomist Turner[114]has shown so clearly, it is found that the convolutions of the sensory and motor centres do not present any great differences in the brain of a child, a monkey, a Bushman, or of a European man of science, like Gauss; what differentiates these brains is the degree of complexity of the convolutions concerned with association. There, then, is the part of the brain which we want to utilise for the purpose of comparison, reduced by almost a third. But let us suppose that differences of volume and weight are found in these two-thirds of the grey substance. Have we more reason to think that we are approaching the solution of the problem?