Rigid body

“ And if we are to move the muscles must be contracted. And it is, of course, obvious that only those muscles can be set in action which are, according to the immediate situation of the body, free to move. ”

“ The senses that keep track of the position of the body and of individual muscles are known respectively as the equilibrium sense and the muscle-and-joint sense. The equilibrium sense has as its organ a part of the internal ear. Deeply imbedded in the bone is a series of chambers and canals lined with a delicate membrane and filled with liquid. ”

“ But I think that we are more averse to assent on false grounds than to anything else which is contrary to nature. Now of the limbs, that is to say, of the parts of the body, some appear to have been given to us by nature because of the use which, they are of to us, as, for instance, the hands, legs, and feet, and also those internal organs of the body, of which I may leave it to the physicians to explain the exceeding usefulness ”

“ We speak of pushing when we propel something away from a body, of pulling when we draw something toward it, yet, as we have just seen, each can be accomplished merely through the contraction of a set of muscles, acting on differently disposed levers. All the bodily activities are reducible to such muscular contractions, and the diversified movements in which the organism constantly indulges are merely due to the large number and elaborate arrangement of the bony levers upon which these muscles are operated. ”

“ This assumption is supported by the consideration that with the lateral sinuous movement of the body, and with the rigidity of the tissues caused by increasing differentiation, the formation of alternating regions of greater and less motility was of considerable advantage to the individual, and rendered possible a further elongation of the body. ”

“ The equilibrium of nature is constantly preserved; for in walking, leaping, running, &c., similar precautions are taken. By the flexibility of our bodies in striking, according to the proportionate force meant to be employed, the body is first drawn back, then the limb propelled forward, bringing with it the weight of the body. ”

“ In the same way the bodily forms and their motion are devoid of life, the arms, for example, are glued to the body, the legs are not divided, or are clumsily moved, or in angular and constrained modes ”

“ But the moving body, ever tending to fall, needs constant support, if it is to move in a true horizontal line. 'What, then,' he asked himself, 'will give constant support to a moving body?' And his answer was 'Human legs!' That was the discovery that immortalised his name! ”

“ Thus the same organ gives us the perception of body as resisting force, and as occupying space; and by combining these conditions we have the conception of solid extended bodies. In reality, this resistance is inevitably presented to our notice in the very facts from which we collect the notion of extension. For the action of the hand and arm by which we follow the forms of objects, implies that we apply our fingers to their surface; and we are stopped there by the resistance which the body offers. ”

“ Formation of Habits.—The co-ordination of the two limbs is after all only a small portion of walking. The body must be held erect, the curve of {230} the spine must be managed so that the center of gravity is kept well within the base, and gluteal and femoral and calf muscles must all be co-ordinated with one another. ”

“ Would it shock our nervous sensibilities, if our next-door neighbor the philosopher, or some near-by grave and reverend doctor of divinity, or even the learned judge himself, should give unmistakable evidence that he had in his body the two hundred and odd bones and the five hundred and more muscles, with all their fit accompaniments of joints and sinews, of which the anatomists tell us? ”

“ But in all these studies there are certain distortions of the human body. These forms are either too aspirant or too convulsive so that one is unpleasantly reminded of the muscular sensations of cramped arms and benumbed legs. ”

“ All the great motions of the body are caused by the movement of some of the bones which form the framework of the system; but these, independently of themselves, have not the power of motion, and only change their position through the action of other organs attached to them, which, by contracting, draw the bones after them. In some of the slight movements, as the winking of the eye, no bones are displaced. ”

“ All manner of movements are produced by muscles pulling sometimes with and sometimes against each other. But you will find when you come to examine them that all the movements of which your body is capable depend at bottom on this—that certain muscular fibres, in obedience to a something reaching them through their nerves, contract, shorten, and grow thick, and so pull their one end towards the other, and that to do this they must be continually supplied with pure blood. ”

“ For the body itself is "fearfully and wonderfully made." Supported by over two hundred bones, which are welded together by ligaments and ten­dons, and again overlaid by hundreds of muscles—the bands and pulleys by which action and locomotion become possible—permeated by thousands of nerves which give sensibility and vitality to the living mass, and clothed by a soft and flexible skin which charms at once the eye and the touch. ”

“ How far this differentiation may go when it has endured generation after generation and is at last crystallized into a set type, is well known; just as by training the muscles of porters, tumblers or fencers develop in each individual, so the muscles develop in those portions of our body most animated by the mind—in our face and hands, especially, have there occurred through the centuries fixed expressions or types of movement. ”

“ The muscular tissue is the most abundant of all the tissues, forming about 41 per cent of the weight of the body.
Properties of Muscles.—The ability of muscular tissue to produce motion depends primarily upon two properties—the property of irritability and the property of contractility. Irritability is that property of a substance which enables it to respond to a stimulus, or to act when acted upon. ”

“ Within the body itself we have sense organs also, particularly in the joints and tendons and in the muscles. These give us the sensations which are the basis of our perception of motion, and of the position of the body and its members. ”

“ Movements often pass to fixed attitudes and postures of limbs or body, disturbing the normal balance between flexors and extensors, the significance of which as nerve signs or exponents of habitual brain states and tensions Warner has so admirably shown. ”

“ The first of these classes,—that which includes the various modifications of resistance,—I examined at great length, and showed, I trust, that it is not to our organ of touch we are indebted for these, but that they are feelings of another sense, of which our muscular frame is the organ,—the feelings, in short, of which every one must have been conscious, who has attempted to grasp any body, or to press against it, when the full contraction of the muscles must, of course, have been impeded. ”

“ Why need I speak of the bones, those supports of the body, whose joints are so wonderfully contrived for stability, and to render the limbs complete with regard to motion and to every action of the body? Or need I mention 309the nerves, by which the limbs are governed—their many interweavings, and their proceeding from the heart,236 from whence, like the veins and arteries, they have their origin, and are distributed through the whole corporeal frame? ”

“ Hence her flesh is naturally yielding, is easily com­pressed, and when the muscular fibre is weakened by child-bearing, the weight of the bones, or the advance of age, the softer portions of the body be­come flaccid, and the whole assume another form. In early life, when the circulation is brisk and the nervous system energetic, one can appreciate the exclamation of Gray—
"No stubborn stays her yielding waist embrace." ”

“ Legs are being formed or moulded into jaws, the anterior segments are fusing into a head, and their ganglia into a brain; an external skeleton is developing. Furthermore the increase of the muscular and nervous systems must be accompanied by increased powers of digestion, respiration, and excretion. Practically the whole body is being recast. We insist only on the necessity of simultaneous and parallel changes in muscles, nerves, and nerve-centres; though what is true of these is true, in greater or less degree, of all the other organs. ”

“ For the hand, to take an example, requires one property to enable it to effect pressure, and another and different property for simple prehension. For this reason the active or executive parts of the body are compounded out of bones, sinews, flesh, and the like, but not these latter out of the former. ”

“ The normal poise is that in which the body is deli­cately adjusted around its center of gravity so as to move easily in any direction, with the least expenditure of nerve and muscular force and in its perfection is expressive of a balanced, self-controlled mental and physical make-up. ”

“ As, however, we trace out the gradual development of the more complex animal forms, we see coming forward into greater and greater prominence the arrangement of the tissues in definite ways to secure mechanical ends. Thus the entire body acquires particular shapes, and parts of the body are built up into mechanisms, the actions of which are to the advantage of the individual. ”

“ The motions of those muscles, which are affected by lascivious ideas, and those which are exerted in smiling, weeping, starting from fear, and winking at the approach of danger to the eye, and at times the actions of every large muscle of the body become causable by our sensations. And all these motions are performed with strength and velocity in proportion to the energy of the sensation that excites them, and the quantity of sensorial power. ”

“ HOW WE STAND ERECT.—The joints play so easily, and the center of gravity in the body is so far above the foot, that the skeleton can not of itself hold our bodies upright. Thus it requires the action of many muscles to maintain this position. ”

“ This movement is executed by means of a muscle under the skin which covers nearly the whole body, and which contracts in a similar manner to a bag drawn together by a string. Many other animals are similarly furnished with a fine muscular layer which covers the body. ”

“ At these times he will throw his body into almost every conceivable posture—twisting, turning, bending, stooping, the arms down, forward, back, and over his head, the muscles of the limbs and entire body flexed almost to the point of tremor, the fingers spread, and the muscles rigidly tensed. ”

“ Although no anatomist, he knows every muscle and sinew whose suppleness gives ease to the body, and so moulds and manipulates them that we lose the rigidity of our mechanism, and become plastic in his hands. He turns us upon our face, repeats the same process upon the back, and leaves us a little longer to lie there passively, glistening in our own dew. ”

“ And since the nuscular system works under the control of the nervous system and becomes moulded by the activities evoked in it by the nervous system, and since the muscles in turn largely mould the structure of the skeleton, we shall regard the structure of all the body as in a large measure the product of experience accumulated by transmission from generation to generation. ”

“ They all possess the common features of friction applied with the hand to the skin, compression of the muscles with the hands, and passive movements of the different articulations of the limbs and body. ”

“ That the construction and organization of the human frame is in all men essentially the same. They have similar solids and fluids, viz., bones, cartilages, tendons, nerves, muscles, veins, arteries, flesh, blood, and other juices, body and parts, or members. ”

“ Again having seen human bodies dissected one knows how the bones lie, and the muscles and sinews, and all the order and conditions of anatomy, so that it is possible with greater security and more correctness to place the limbs and arrange the muscles of the body in the figures we draw. ”

“ If one line, proceeding from a central particle, be understood, every line, which can proceed from it, is also understood. If that central point be a part 36 of the human body, it is plain that as the hand, passing along a line in a certain direction from that centre, has certain muscular actions, passing along in another direction, it has muscular actions somewhat different. When we say muscular actions somewhat different, we say muscular feelings somewhat different. ”

“ What is man but a mass of thawing clay? The ball of the human finger is but a drop congealed. The fingers and toes flow to their extent from the thawing mass of the body. Who knows what the human body would expand and flow out to under a more genial heaven? ”

“ On the contrary, they include changes and movements in all of the so-called involuntary muscles, and in every kind of bodily structure. They include changes and movements in every part of the physical organism, from changes in the action of heart, lungs, stomach, liver and other viscera, to changes in the secretions of glands and in the caliber of the tiniest blood-vessels. A few instances such as are familiar to the introspective experience of everyone will illustrate the scope of the mind's control over the body. ”

“ The conformation, the arrangement, the texture, the delicacy of the organs, as well exterior as interior, which compose men and animals, render their parts extremely mobile, or make their machine susceptible of being moved with great facility. In a body, which is only a heap of fibres, a mass of nerves, contiguous one to the other, united in a common center, always ready to act ”