Pedagogical Anthropology, Maria Montessori [online e book reader TXT] 📗

with delicate contours; it might be described as "frail and naked"; for the word nakedness precisely expresses the absence of those defences with which the cranium of the anthropoid ape is so abundantly provided. Accordingly, the human cranium is undefended by soft tissues; and even the bony walls themselves are far from thick. If we take a transverse section of the bones of the cranium, we find that they are formed of two very thin layers of bone united by a porous, osseous substance; the external layer is in direct contact with the muscles of the scalp, and the internal layer with the brain. These two layers differ widely in their degree of elasticity: the external layer is so elastic that if it receives a bruising blow (provided this is not so heavy as to surpass its limits of elasticity) it will yield even to the point of touching the inner layer and then spring back to its original position without leaving any perceptible trace of the blow received (this is especially true in the case of infants),[36] while the inner layer is so unelastic as to appear almost as brittle as glass: so much so, for example, that the indirect shock of the same contusion may cause it to splinter into fragments, which may either penetrate the substance of the brain, or produce hemorrhages, or inflammatory reactions in the meninges—and sometimes may constitute the sole cause of epilepsy, and various forms of inflammation of the brain (even resulting in idiocy), and sometimes of meningitis and death.

Contusions on the heads of children, and in general blows resulting from falls or other causes, must be taken into serious consideration, in the history of the individual, even though they have left no profound traces externally.

This human characteristic of nakedness, of the absence of powerful bodily defences, is not limited to the head alone, but is diffused over the entire morphological organism. Man, considered as an animal, is weak; he is born naked and he remains naked, and destitute of those natural defences which explain the endurance and the survival of other species; neither the fur nor the plumage of mammals and of birds nor the bony shields of reptiles and scales of fishes serve as defences for this vertebrate, who has raised himself to the highest eminence in the zoological scale; neither the muscular strength and powerful teeth of the felines, nor the talons of the birds of prey have been his arms of conquest.

Nevertheless, man who has conquered the earth and overcome all his powerful biological enemies, owes his survival, equally with all other living creatures, to his victory over other animals and over his environment. Wherein lies the special strength of this little, feeble being, who has become the lord of the earth? It lies in his brain. The arms of this conqueror are wholly psychic. It is his intelligence which has prevailed over the might of other animals and enabled him to acquire the means of adapting himself to his environment, or else of adapting his environment to himself. His intelligence, which sufficed him as a weapon with which to achieve victory in the struggle for existence, is also the means which still permits him to continue on the road toward self-perfectionment.

The morphological importance attached by anthropologists to the cerebral cranium depends precisely upon this: that it is the envelope of the brain. If we examine the interior of the human cerebral cranium, we find that it has adapted its bony contours so faithfully to those of the soft tissues that it bears the imprint of the various parts of the brain (cerebrum, cerebellum), the convolutions, and even the blood-vessels of the meninges. Accordingly, a study of the cerebral cranium amounts to an indirect study of the brain itself.

Characteristics of the Human Cranium.—The characteristics of the human cranium are all associated with the great development of the volume of the brain. Let us assume that we have an elastic vessel, representing in form an animal cranium, open at the base through an orifice corresponding to the occipital foramen. If we inflate this vessel, it will not only begin to enlarge at the expense Of its folds (ridges), and to stretch and distend its walls (thinness and fragility of the cranial bones); but furthermore it will undergo a change in form, acquiring a more pronounced rotundity and pushing upward in its anterior part above the face. This part, rising erect above the face, and determined by the volume of the brain, is the forehead. Animals do not have an erect forehead; their orbits continue backward in an almost horizontal line, giving them an extremely receding brow. Corresponding to this preponderance of the cerebral portion, the facial portion retires below the brow, the mandibles do not extend beyond the anterior axis of the brain, and are so far diminished in volume that they assume, as compared with animals, a new function; in short, the mouth is no longer merely the organ of mastication, but also the organ of speech; its animal part has been spiritualised.

The Evolution of the Forehead.—Inferior Skull Caps; the Skull of the Pithecanthropus; the Skull of the Neanderthal Man. The forehead is so distinctly a human characteristic that mankind has not needed the help of anthropology in order to realise its importance—and as a sign of superiority, nobility or sovereignty, has placed upon the forehead the crown of laurel, or the crown of nobility or kingship.

Has the forehead always been a human characteristic, or have we acquired it little by little? Such a problem is associated with the evolution of the brain. There are in existence certain remains of the skeletons of primitive men, which show them to have possessed a cerebral cranium inferior in volume to that now attained by the human species; and in these remains the forehead is also profoundly different from that of to-day, in that it is much lower and slants backward, while the supraorbital arches are very prominent. Such is the evidence of the "cranial caps," discovered in the early geological strata.

In the tertiary strata of the island of Java, which in that remote epoch of the earth's history must, together with Sumatra, have formed part of the continent of Asia, which is considered as the "laboratory of races," a skull was found by Dubois which raised the problem whether it should be classed as that of an ape superior to those now existing, or of a primitive man. Prior to this discovery, it had been maintained that man did not make his appearance until the quaternary period. This supposed primitive man was called by his discoverer the Pithecanthropus, pithecanthropus erectus.

Remains that are unquestionably human occur in the quaternary period, in which however skeletons are very rare, as compared with relics of human labour or social life, relics which are found scattered everywhere throughout Asia and Europe as well (chipped flints). The various remains of skeletons show us skulls much inferior to those of modern man, but superior to that of the pithecanthropus. In treatises of general anthropology reproductions are given of human crania known as the Spy or Neanderthal type, belonging to the epoch when the gigantic mammoth still roamed the earth. The forehead is very low and receding and the orbital arches are enormously developed; while the cerebral capacity calculated from the cranial dimensions is inferior to that of modern man.

Consequently, as the brain increases in volume in the course of the revolution of the race, the cranium not only shows a corresponding volumetric increase, but at the same time alters its form, thus producing the forehead which little by little rises from a receding to an erect position, and becomes high where it was formerly low, while at the same time the prominent orbital arches disappear. Accordingly, we may consider the forehead as the skeletal index of the cerebral volume, and hence of the relative anthropological and intellectual superiority.

In addition to its above-mentioned value, it also furnishes us with a biological principle of much importance: the relation between the volume and form of the cranium.

While the volume has a significance that is relative to the mass of the body, the significance of the form is absolute.

Let us examine these two skulls: normal human skulls of our own epoch; one of the Celtic race (Fig. 46) and the other Sardinian (Fig. 43); that of the Celtic race is much larger and rounder; that of the Sardinian is very much smaller and more elongated.

If we were considering only the volume, we might say that it was simply a case of a microcephalic and a macrocephalic: two terms (microcephaly and macrocephaly) that fall within the province of pathology. On the contrary, these two skulls are normal, but they belonged to individuals characterized by differences of race; the one (small skull) having a low stature; the other (large skull) having a tall stature.

The volume of the head therefore bears a relation to that of the body; the volume has a relative significance. But the form in both of them reveals a state of normality; the two skulls have a high and erect forehead, and exhibit in their whole contour a fine and regular development. Therefore the form has an absolute significance. It even proves to us the normality of the volume, a fact which could not be determined by the volume alone.

Another mechanical correspondence between volume and form is disclosed when we compare the skull of a new-born child with that of an adult. The skull of the new-born child is much smaller in volume; but the form shows the relatively enormous volumetric development of the brain; in fact the skull is protuberant and the forehead bulges forward above the face (front bombé), while corresponding to this index of cerebral development is the enormous preponderance of the cerebral cranium over the facial cranium, which is so small as to be almost reduced to a simple rudiment.

Hence the form by itself alone reveals the infantile character of the cerebral volume, which, in relation to the bulk of the body is of far greater dimensions than in the adult. In fact, if a child simply increased in volume and its growth was not the sum total of a morphological evolution, the adult man would become a monster; his macrocephaly would be so exaggerated that his neck could not sustain the weight of the head (If the relations between the proportions in infancy were maintained through life the adult man would have a head with a perimeter of 130 centimetres, = 4 ft. 3 in.).

Aside from its mechanical relations to the volume, the form has characteristics dependent upon biological factors, such as the sex and the race. The female cranium in fact has a straighter forehead than the male and the orbital arches are absolutely wanting, while the entire surface of the cranium is smoother and more rounded.

Similarly, the different races exhibit forms determined by biological factors and not by mechanical causes—for instance, the degree of dolichocephaly (elongated cranium) and of brachycephaly (short cranium).

Hence the form is life's manifestation not only of the characteristics proper to the species, but also of the mechanical adaptations demanded by the material composing the body.

It may be said that the volume and the form of the cranium are dependent upon two different biological potentialities: the volume is mainly determined by the cerebral mass; the form, on the contrary, is mainly determined by the bony structure—no matter how completely form and volume coincide in their reciprocal mechanical relations.

That is, the attainment of a given volume of head depends upon the development of the brain; the bone follows this development passively, is the index of it, the skeletal representation of it, but never the determining factor.

At one time it was thought, on the contrary, that a precocious ossification of the cranial cavity would arrest the development of the brain; microcephaly was