is," says Forbes,* "very active and tenacious of life; before dying, assuming all manner of strange shapes, doubling itself | up, and turning its organs inside out in a terrific manner, giving up the ghost with convulsions as fearful as those of a popular actor in the death-scene of a tragedy." Or THE PHYSICAL HISTORY OF MANKIND. CHAPTER THE FOURTH. THE SKULL, AS LIABLE TO VARIETY IN THE should you desire to witness the union of ON THE SKIN, HAIR, EYES, AND BONES OF qualities that are rarely combined in the same individual, endeavour to secure some specimens of Sarsia tubulosa, a species that at times is taken rather abundantly on some parts of the coast. Being kept," says Professor E. Forbes, "in a jar of salt water with small crustacea, they devoured these animals, so much more highly organised than themselves, voraciously, apparently enjoying the destruction of the unfortunate members of the upper classes with a truly democratic relish. One of them even attacked and commenced the swallowing of a Lizzia octopunctata, quite as good a Medusa as itself. An animal which can pout out its mouth twice the length of its body, and stretch its stomach to corresponding dimensions, must indeed be 'a triton among the minnows,' and a very terrific one too. Yet is this ferocious creature one of the most delicate and graceful of the inhabitants of the ocean-a very model of tenderness and elegance." I The IN the preceding chapters we have seen that however numerous may be the points of agreement between man and the lower animals, he is clearly distinguished from them by characters that are unmistakeable in all circumstances in which he may be found. Yet numerous as are the features which distinguish man from the highest monkeys, at first sight they do not appear to be more decided than the differences which exist between the various races of men. How many are the characters, for instance, by which an individual of the black races of Africa is distinguished from one of the white races of Europe! black skin, the curly hair, the retreating forehead, the projecting jaw, the whole frame of the one-how strongly it contrasts with the fair complexion, the long hair, the prominent brain, the retreating jaw, of the other! Yet when we come to examine accurately the differences between the various races of men, we shall find that every recorded dissimilarity may be comprised within limits very much narrower than any that distinguish man from the lower animals. Thus, although we find considerable variety in the form and length of the foot in man, we never find anything approaching the difference that exists between man and the orang-utan. We might Most men never distinguish their own decisions from what is right; not consider-ter of difference between man and man, thus take up every individual characing that if others are not of the same opinion as themselves, neither are they of the same opinion as others. This arises from that pride which makes every one assume as a fixed principle that he is right. This pride is particularly the lot of the ignorant; and hence the saying, that "he is quite proud of being ignorant." Socrates was just the reverse of such men: after he had learned all that the wisest of his day could teach, he declared that he knew nothing. Here for the present I must pause. have more to tell you respecting this division of the animal kingdom, but the "Printer's devil" may not share in my admiration of those graceful creatures, and may be quite ready to exclaim, "Holdenough." * Thaumantias Melanops, Forbes, p. 45... and show that whatever may be its extent amongst the human races, it is much greater between man and the lower animals. There is, in fact, no one physical feature characteristic of the degradation of the lowest races of men in which man does not more his race than he does the most highly closely resemble the highest specimens of developed forms of the mammalia. Let us then now proceed to examine some of these differences in the appearance and structure of man, and the agencies to which they have been ascribed as causes. One of the most obvious, although per-openings (Fig. 4, b b) which are the terhaps not the most constant, differences minations of the glands (d d d) that between the races of men is the colour yield perspiration. These furrows and of the skin. This varies in all possible shades amongst the different varieties of mankind-from the fairest blondes of the European races to the deep ebony of those of Africa. All the observed varieties of shade, appear to depend on the presence or absence of a peculiar set of cells in the skin. In order, however, that this may be understood, we must speak a little in detail of the structure of the skin. Although apparently very simple in its structure, the skin is nevertheless a very compound organ; and when we consider the important functions it performs, and its relations to the rest of the body, we shall not be surprised at this. It is not only the seat of common sensation, but by means of the vapour it constantly emits in the form of perspiration, it becomes the great regulator of the heat of the body. For these purposes it is supplied with nerves, blood-vessels, and glands. On examining à portion of skin from the palm of the hand, or sole of the foot, from without inwards, we find that externally it presents a number of furrows, or lines, which are tolerably constant in particular b. pores are in the upper layer of the skin, It has always been a question of interest to the ethnologist, as to whether the presence of these pigment cells could be traced to any external influence. As far as inquiries have extended at the present day, it appears that the tendency to form these cells is dependent in some measure on the exposure of the skin to light. As a rule, it is found that where the sun's rays are most direct, in other words, where there is the greatest amount of light, that the skins of human beings exhibit the greatest tendency to develop these cells. The darkest skinned races are inhabitants of the tropics. This is not a mere coincidence; for when the laws of light are studied, we find that its influence on organic beings is such that we are led to the conclusion that light is capable of affecting the organic constitution of bodies which are exposed to its action. In the vegetable world, the most brilliant colours, the most powerful scents, and the most poisonous secretions, are all produced under the agency of intense light. That exposure to light has an influence in the development of the colour of the skin, is also supported by the fact, that the children of all dark races are born fair, and do not become black till they have been exposed to the light of the sun. At the same time that there exists this evidence to support generally the position that the light of the sun develops the dark colour of the skin, there are many facts to show that the growth of these cells at all, is under the control of circumstances over which this external agent has no influence. Thus occasionally there are born amongst the black races individuals in whom these pigment cells are not developed, and they remain white throughout their lives. In certain parts of the body these cells are found in fair races, as in the hair and the eyes, but even amongst these races such individuals are born. They are known by the name of Albinos, and are remarkable for white hair, and the absence of pigment cells in the eyes, which gives the interior of these organs a red colour, from the blood-vessels reflecting the colour of the blood. This occurrence is also not unfrequent amongst domesticated animals. From these facts we must regard the dark colour of the skin as due to the constant action of light, upon a system in which there is a natural tendency to develop the pigment cells. Although colour so remarkably and evidently distinguishes human beings from one another, yet we find that throughout nature it is one of the least permanent marks of distinction between one animal and another, and even one plant and another. It will be well to bear this in mind, for when we come to speak of the great question as to whether there is more than one species of man-whether God has created two or more kinds of men, with different characters, habits, and destinies, we shall find it important to form a just estimate of the individual characters which distinguish man. Closely connected with the colour of the skin is the appearance and colour of the hair. With the dark black skin the hair is black, crisp, and woolly; whilst with the red or yellow colour of the skin the hair is seldom woolly, or even curly, but is black, lank, and straight. On the other hand, with the fair skin the hair is never woolly, and frequently of a light colour. The hair is an appendage of the skin, and is formed in little depressions of this organ, which are called hair follicles (Fig. 5, a). These follicles extend to various depths of the corium, and are always lined with cells of the same nature as those found in the epidermis. It is through the secretions of these cells that the hair (b) is first formed in the follicle, and then gradually thrust out from below, upwards, so that what is called the growth of the hair is secured. The hair is not a living part of the body, it has no blood-vessels or nerves, and is similar in its organic nature to the epidermis itself. On examining a hair under the microscope, it is found to consist of three parts-first, of a coating of finely imbricated scales, the projecting edges of which give to the hair a serrated appearance; secondly, a fibrous substance, made up of straight, rigid, longitudinal fibres, flattened and pointed at each end, and broad in the middle. These fibres are the result of the cells of which we have before spoken, formed in the interior of the follicle, and which, as they pass upward to form the shaft of the hair, are submitted to a considerable amount of compression in the upper part of the follicle. It is in these fibres of the hair that the colouring matter exists which gives the peculiar colour to the hair. This depends on the presence of the same kind of cells in the follicle which we before found giving colour to the skin. When the pigment cells are numerous in the hair-follicle, the hair is black; and it is of varying shades of lightness according as these cells are absent. It is the perfect absence of these cells that gives to the hairs of the Albino and the aged their silvery white appearance. The same cause produces the colour of the hairs of the skins of various animals. The white hairs are destitute of the pigment cells, whilst in coloured hairs they are present in various proportions. In some hairs there is a third portion, called the medulla, or pith. It consists of little masses of granular particies and corpuscles, which form a dark line in the middle of the hair. It is not, however, an essential part of the hair, as it is found very frequently absent. In the skin are a number of small glands, whose function it is to secrete oily matter, which is thrown out on the surface, and in most cases it is found that these sebaceous glands open into the hair-follicles (Fig. 5, d d). Their function is probably to facilitate the projection of the hair from its follicle, as well as to supply it with the oily matter which is necessary to its healthy condition. colour of hair with special conditions of the skin. At the same time, we see here again that conditions of the hair come on independent of the influence of heat and light. The children of fair parents are sometimes born with black curly and almost woolly hair. In animals-for instance, the sheep-where the hair is normally white, we constantly find the occasional occurrence of a lamb that is perfectly black. Another instance of the colour of the hair being independent of climatal and hereditary tendencies, is seen in the suddenness with which it sometimes changes from black to grey, and which is at present quite unaccounted for. Another of the points of difference between one of the great sections of the races of mankind and the rest, is the position of the eyelids. In most of the fair races, and also of the black ones, the upper and lower eyelids will meet on a line drawn at right angles with one passing through the chin and nose, as seen in the eye at Fig. 6. upon a straight line, but that they are oblique, as seen in Figs. 7 and 8. The reason of this difference consists in the upper eyelid of these races being larger, and more ample, so as fully to cover up the lachrymal apparatus, which is to a greater or less extent exposed in the black and white races. This gives to the eye a differs from that of the black races, are those which form the upper jaw. In the black races, as in Fig. 3, the upper jaw projects, and the lower jaw is brought on a level with it, so that the mouth forms a kind of muzzle. The teeth are in this case oblique, and in such case the skull is said to be prognathic. When, however, the teeth are on a line with the bone of the nose, and the upper and lower jaw nearly perpendicular with the lower edge of the frontal bone, then the skull is termed orthognathic. Another point of importance is the general shape of the head, arising from the Fig. 8.* dull and heavy appearance, and also serves to render the eye apparently smaller. This condition of the eye has been observed in some of the lower animals, and it has been supposed to be a provision of nature, for protecting the lachrymal apparatus from the effects of cold in rigorous climates. Fig. 9.* Another peculiarity in connexion with the eye is its colour. That part of the structure of the eye which gives to it its peculiar structure, is a membranous veil, called the iris, which has a power of contracting and expanding, thus affecting the size of the aperture, which we call the pupil. The cause of the colours which this membrane assumes is the same as that which produces the colour of the hair and the skin; and we find that, as a rule, where the skin is darkest, there also the eyes are darkest. Pigment cells are, however, always deposited in the iris, in all races, but it is only among the fair-skinned nations that we find the lighter colours of blue and grey pre-made broad-such heads are termed dolivailing. Amongst the points of structure which differ in the various races of men, and produce obvious external differences, there are none more decided than those depending on the form of the bones of the skull. The differences in the general form of the skull which occur may be seen by comparing the negro skull (Fig. 3, p. 175) with the skull of the skeleton (Fig. 1, p. 118). The parts in which the skull of the European most greater or less projection of the parietal bones (Figs. 8 and 9, e e). In the skulls of some nations, as in the Eskimo (Fig. 9), these bones are remarkably depressed, at the same time the zygoma, c c, are large; thus the head is narrowed, and the face khokephalic, or long-headed, whilst those in which the parietal bones project are brakhykephalic, or short headed. Although such forms of the skull characterize great groups of men, yet individuals are found amongst all races in which one or other form may predominate over the prevalent one. The other parts of the skull which are liable to differences are the bones of the * Skull of an Eskimo:-a a Occipital bone.b Foramen magnum.-c Zygoma.-d Upper jaw. -e e Parietal bones. |