Craniology

“ For our skull is as a kind of flower-pot, and holds the soil from which we spring, that is to say the brain; our mouth and stomach are roots, in two stories or stages; our bones are the trellis-work to which we cling while going about in [Pg 138] search of sustenance for our roots; or they are as the woody trunk of a tree; we are the nerves which are rooted in the brain, and which draw thence the sustenance which is supplied it by the stomach; our lungs are leaves which are folded up within us, as the blossom of a fig is hidden within the fruit itself. ”

“ Some parts of the head we use for other purposes, as the mouth to eat and speak with, and the nose to smell and breathe with. The part we think with is inside of the skull, safely placed in a little room at the top and back part of the head. Do you remember the name of this organ which fills the hollow place inside of the skull? We learned some time ago that it is called the brain. It is with the brain that we study and remember and reason. So the brain is one of the most important organs in our body, and we must try to learn all we can about it. ”

“ The Cranial Bones.—The cranium or skull is especially adapted for the protection of the brain and the bones are flat and closely fitted to its surface. They have two layers of bone, the outer and the inner tables, of which the outer is the thicker, and between these is a tissue filled with blood-vessels, the diploë. In the infant, whose brain has not yet attained its full size, opportunity must be left for growth and the skull therefore consists of a number of bones with interlocking notched edges, where growth takes place, but in the adult it forms one solid covering of bone. ”

“ Lastly, with relation to their Use; some serve to support and carry the whole Body, as the Leg-Bones, and others are appointed to grind the Meat, as the Teeth; or else to form some Cavity, as the Skull-Bone, and those of the Ribs.
What are the Parts to be distinguished in the Bones?
They are the Body, the Ends, the Heads, the Neck, the Apophyses, the Epiphyses, the Condyli or Productions, the Cavities, the Supercilia or Lips, and the Ridges.
The Body is the greatest Part, and the middle of the Bone; the Ends are the two Extremities; the Heads are the great Protuberances at the Extremities ”

“ In the living rabbit this hollow space is filled up with the brain. The skull, in fact, is a box of bone to hold the brain, a bony brain-case. This bony case fits on to the top of the vertebræ of the neck in such a way that the rounded opening we spoke of just now is placed exactly over the top of the tunnel or canal formed by the rings or arches of the vertebræ. If you were to put a wire through the arch of the lowest vertebra, you might push it up through the canal formed by the arches of all the vertebræ, right into the brain cavity. ”

“ We really see the skull pared off and the surface of the brain. The surface shows quite normal convolutions. Under a microscope some of them might, perhaps, show some differences in size and form, but now we can only see a common surface. We see, plainly also the well-known gray matter, composed of nerve-cells and deposited all along the surface in small convolutions,—and, for the benefit of laymen, I add that modern physiologists designate this gray matter as the seat of consciousness, thought, talent, and recollections. ”

“ Perhaps some of my readers may not be aware that the bone of the skull consists of an outer and inner plate, with a variable arrangement of cells between them. In many animals, such, for example, as man, where the jaws are comparatively feeble, and the teeth small and light, the size of the skull is practically that of the brain, to which it affords a covering. The same structure may be observed in the skull of the common sparrow, where, as in man, the two bony plates are set almost in contact. ”

“ Most conservative of all has been the structure of the cranial region of the skull, that surrounding the brain, and in consequence it furnishes the most reliable characters for the discrimination of the larger groups, the subclasses or superorders. ”

“ Now comes the important question, can we discern, between the lowest and the highest forms of the human cranium, anything answering, in however slight a degree, to this revolution of the side and roof bones of the skull upon the basicranial axis observed upon so great a scale in the mammalian series? ”

“ Brain cavity absolutely larger, and, in proportion to the size of the body, much more capacious than in the Simiidæ, yet less so than in the Hominidæ. Capacity of the skull about two-thirds the average of that of man. ”

“ The anatomy of the human form, contemplated in reference to that of all other species of animals to which it bears comparison, constitutes the study of the comparative anatomist, and, as such, establishes the science in its full intent. But the anatomy of the human figure, considered as a species, per se, is confessedly the humblest walk of the understanding in a subject which, as anatomy, is relationary, and branches far and wide through all the domain of an animal kingdom. ”

“ It may be observed that, with the ascension of these animals, the relative size of the brain-case, or skull, increases with a proportionate diminution of the bones of the face, and of the projection of the jaws in front of the orbits. ”

“ If we contemplate the interior of a skull, we shall at once perceive that the inner table has every where penetrated as far as it could into the recesses which open on the surface of the brain. Every convolution has hollowed out its corresponding mould in the vitreous table ”

“ The reader will understand that organs located for observation on the face are organs of the brain lying behind the face, which may be reached and stimulated through it, as other organs are reached and stimulated through the cranium and integuments. The contour of the face cannot reveal the organs behind it by physical necessity, as does the contour of the skull, yet observation induces me to rely upon estimates based on facial development. ”

“ The head and skull offer a number of clues to the controlling secretions in the blood and tissues. Whether the forehead is to be broad or narrow, the distance between the eyes, the character of the eyebrows, the shape and size and appearance of the eyes themselves, the mould of the nose and jaws and the peculiarities of the teeth, are all so determined. The skin, in its color, texture, the quantity and distribution of its fatty and other constituents, eruptions and weather reactions, is influenced. ”

“ They are merely the expression of a great consistent system, and are in architecture what is often found in animal anatomy,—a bone, or process of a bone, useless, under the ordained circumstances of its life, to the particular animal in which it is found, and slightly developed, but yet distinctly existent, and representing, for the sake of absolute consistency, the same bone in its appointed, and generally useful, place, either in skeletons of all animals, or in the genus to which the animal itself belongs. ”

“ His body has long since mouldered away and mingled with the parent earth,—this skull alone remains; and yet the time will surely come, and cannot be far distant, when "the bones shall come together—bone to his bone"; when the sinews and the flesh shall come upon them, the skin cover them, and the breath entering the body the dead shall live! ”

“ If we pursue our researches into the interior of this animal, we find within the framework of the skeleton a great cavity, or rather, I should say, two great cavities,—one cavity beginning in the skull and running through the neck-bones, along the spine, and ending in the tail, containing the brain and the spinal marrow, which are extremely important organs. ”

“ The cranial and facial characteristics, which are the result in man of the considerable volume of his brain, the atrophy of the nasal fosses, and of their numerous posterior cavities, which has brought about the disappearance of the muzzle, the compensatory perfection of the touch and the vision, which, with the modifications necessitated by the equilibrium of the skull, have contributed to a bipedal attitude and an entire new series of differential characteristics—are details also. ”

“ Among the vertebrata in general, evolution is marked by an increasing heterogeneity in the vertebral column, and more especially in the segments constituting the skull: the higher forms being distinguished by the relatively larger size of the bones which cover the brain, and the relatively smaller size of those which form the jaws, &c. Now, this characteristic, which is stronger in Man than in any other creature, is stronger in the European than in the savage. ”

“ Now, those skulls which have the largest and strongest jaws and the widest zygomatic aperture, have the muscles so large that they meet on the crown of the skull, and deposit the bony ridge which supports them, and which is the highest in that which has the smallest cranial surface. ”

“ In the interior of the skull should be noticed a large plate of bone which extends inwards and separates the great brain, or cerebrum, from the lesser brain, or cerebellum, and prevents the jarring of that important organ likely to arise from the animal’s vigorous movements. ”

“ It will be obvious, from an inspection of the diagrams, that the basicranial axis is, in the ascending series of Mammalia, a relatively fixed line, on which the bones of the sides and roof of the cranial cavity, and of the face, may be said to revolve downwards and forwards or backwards, according to their position. ”

“ For, inasmuch as the brain in all mammals completely fills the cranial cavity, it is obvious that a cast of the interior of the skull will reproduce the general form of the brain, at any rate with such minute and, for the present purpose, utterly unimportant differences as may result from the absence of the enveloping membranes of the brain in the dry skull. ”

“ The largest part of the skull is that which is at once the receptacle and the protector of the brain, a part which, when unmodified by external pressure, premature synostosis, or other adventitious conditions, owes its form to that of the cerebral hemispheres which it contains. Speaking in this city of George and Andrew Combe, I need not do more than indicate in this matter that observation and experiment have established on a firm basis certain fundamental points regarding the growth of the brain. ”

“ From this room of anatomy you are conducted to the room of histology, in which the eye is aided by powerful microscopes and made acquainted with the smallest arteries of the human body, which in life are of the greatest known importance, remembering that in the room of histology you are still studying anatomy, and what that machinery can and does execute every day, hour, and minute of life. ”

“ These structures, underlying the skull, are all that appear [s] at first of the brain box. In front, and separate from the cranium, are the nasal organs (n.c.) ; the eyes lie laterally to the trabeculae, and laterally to the parachordals are two tracts of cartilage enclosing the internal ear, the otic capsules. ”

“ It is held by a class of naturalists, some of them of the highest standing, that the skulls of the vertebrata consist, like the columns to which they are attached, of vertebral joints, composed each, in the more typical forms of head, as they are in the trunk, of five parts or elements,—the centrum or body, the two spinous processes which enclose the spinal cord, and the two ribs. ”

“ It is this formation which imparts such strength to so thin a set of bones as those which compose the human skull as enables them to protect a sensitive organ like the brain, on which both reason and life itself depend. ”