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In such qua
watch (I mean the chain which passes between | no account can be given from the structure or the spring-barrel and the fusee,) 'which aims at exercise of the part. the same properties, is but a bungling piece of VI. The shoulder-blade is, in some material workmanship in comparison with that of which respects, a very singular bone; appearing to be we speak.
made so expressly for its own purpose, and so inIV. The reciprocal enlargement and contraction dependently of every other reason. of the chest to allow for the play of the lungs, de drupeds as have no collar-bones, which are by far pends upon a simple yet beautiful mechanical the greater number, the shoulder-blade has no contrivance, referable to the structure of the bones bony communication with the trunk, either by a which enclose it. The ribs are articulated to the joint or process, or in any other way. It does not back-bone, or rather to its side projections, ob- grow to, or out of, any other bone of the trunk. liquely: that is, in their natural position they bend It does not apply to any other bone of the trunk:(I or slope from the place of articulation downwards. know not whether this be true of any second bone But the basis upon which they rest at this end in the body, except perhaps the os hyoides:) in being fixed, the consequence of the obliquity, or strictness it forms no part of the skeleton. It is the inclination downwards, is, that when they bedded in the flesh; attached only to the muscles. come to move, whatever pulls the ribs upwards, It is no other than a foundation bone for the arms, necessarily, at the same time, draws them out; laid in, separate, as it were, and distinct, from the and, that, whilst the ribs are brought to a right general ossification. The lower limbs connect angle with the spine behind, the sternum, or part themselves at the hip with bones which form part of the chest to which they are attached in front, is of the skeleton : but this connexion, in the upper thrust forward. The simple action, therefore, of limbs, being wanting, a basis, whereupon the arm the elevating muscles does the business: whereas, might be articulated, was to be supplied by a deif the ribs had been articulated with the bodies of tached ossification for the purpose. the vertebræ at right angles, the cavity of the thorax could never have been farther enlarged by a
Of the Joints. change of their position. If each rib had been a rigid bone, articulated at both ends to fixed bases, I. The above are a few examples of bones made the whole chest had been immoveable. Keill has remarkable by their configuration : but to almost observed, that the breast-bone, in an easy inspira- all the bones belong joints ; and in these, still tion, is thrust out one tenth of an inch: and he more clearly than in the form or shape of the calculates that this, added to what is gained to the bones themselves, are seen both contrivance and space within the chest by the flattening or descent contriving wisdom. Every joint is a curiosity, of the diaphragm, leaves room for forty-two cubic and is also strictly mechanical. There is the inches of air to enter at every drawing-in of the hinge-joint, and the mortice and tenon-joint; each breath. When there is a necessity for a deeper as manifestly such, and as accurately defined, as and more laborious inspiration, the enlargement any which can be produced out of a cabinetof the capacity of the chest may be só increased maker's shop; and one or the other prevails, as by effort, as that the lungs may be distended with either is adapted to the motion which is wanted : seventy or a hundred such cubic inches.* The e. g. a mortice and tenon, or ball and socket.joint, thorax, says Schelhammer, forms a kind of bel- is not required at the knee, the leg standing in lows, such as never have been, nor probably will need only of a motion backward and forward in be, made by any artificer.
the same plane, for which a hinge-joint is sufficient; V. The patella, or knee-pan, is a curious little a mortice and tenon, or ball and socket-joint, is bone; in its form and office, unlike any other bone wanted at the hip, that not only the progressive of the body. It is circular; the size of a crown step may be provided for, but the interval between piece; pretty thick; a little convex on both sides, the limbs may be enlarged or contracted at pleaand covered with a smooth cartilage. It lies upon sure. Now observe what would have been the the front of the knee; and the powerful tendons, inconveniency, i. e. both the superfluity and the by which the leg
is brought forward, pass through defect of articulation, if the case had been inverted : it (or rather it makes a part of their continuation) if the ball and socket-joint had been at the knee, from their origin in the thigh to their insertion in and the hinge-joint at the hip. The thighs must the tibia. It protects both the tendon and the have been kept constantly together, and the legs joint from any injury which either might suffer, have been loose and straddling. There would by the rubbing of one against the other, or by the have been no use, that we know of, in being able pressure of unequal surfaces. It also gives to the to turn the calves of the legs before; and there tendons a very considerable mechanical advantage, would have been great confinement by restraining by altering the line of their direction, and by ad- the motion of the thighs to one plane. The disvancing it farther out from the centre of motion; advantage would not have been less, if the joints and this upon the principles of the resolution of at the hip and the knee had been both of the same force, upon which principles all machinery is sort; both balls and sockets, or both hinges: yet founded. These are its uses. But what is most why, independently of utility, and of a Creator observable in it is, that it appears to be supple who consulted that utility, should the same bone mental, as it were, to the frame : added, as it should (the thigh-bone) be rounded at one end, and chanalmost seem, afterward; not quite necessary, but nelled at the other ? very convenient. It is separate from the other The hinge-joint is not formed by a bolt passing bones ; that is, it is not connected with any other through the two parts of the hinge, and thus keepbones by the common mode of union. It is soft, ing them in their places; but by a different expeor hardly formed, in infancy; and produced by an dient. A strong, tough, parchment-like memossification, of the inception or progress of which brane, rising from the receiving bones, and in
serted all round the received bones a little below * Anat. p. 229.
their heads, encloses the joint on every side. This
membrane ties, confines, and holds, the ends of the binding up of a fracture, where the fillet is al the bones together; keeping the corresponding most always strapped across, for the sake of giving parts of the joint, i. é. the relative convexities and firmness and strength to the bandage. concavities, in close application to each other. Another no less important joint, and that also
For the ball and socket-joint, beside the mem- of the ginglymus sort, is the ankle ; yet though brane already described, there is in some import- important, (in order, perhaps, to preserve the ant joints, as an additional security, a short, symmetry and lightness of the limb,) small, and, strong, yet flexible ligament, inserted by one end on that account, more liable to injury. Now this into the head of the ball, by the other into the bot- joint is strengthened, i. e. is defended from dislotom of the cup; which ligament keeps the two parts cation, by two remarkable processes or prolongaof the joint so firmly in their place, that none of tions of the bones of the leg; which processes the motions which ihe limb naturally performs, form the protuberances that we call the inner and none of the jerks and twists to which it is ordi- outer ankle. It is part of each bone going down narily liable, nothing less indeed than the utmost lower than the other part, and thereby overlapand the most unnatural violence, can pull them ping the joint: so that, if the joint be in danger asunder. It is hardly imaginable, how great a of slipping outward, it is curbed by the inner proforce is necessary, even to stretch, still more to jection, i. e. that of the tibia; if inward, by the break, this ligament; yet so flexible is it, as to op-outer projection, 1. e. that of the fibula. Between pose no impediment to the suppleness of the joint. both, it is locked in its position. I know no acBy its situation also, it is inaccessible to injury count that can be given of this structure, except from sharp edges. As it cannot be ruptured, (such its utility. Why should the tibia terminate at its is its strength,) so it cannot be cut, except by an lower extremity, with a double end, and the fibula accident which would sever the limb. If I had the same,—but to barricade the joint on both sides been permitted to frame a proof of contrivance, by a continuation of part of the thickest of the such as might satisfy the most distrustful inqui- bone over it? The joint at the shoulder compared rer, I know not whether I could have chosen an with the joint at the hip, though both ball and example of mechanism more unequivocal, or more socket-joints, discovers a difference in their form free from objection, than this ligament. Nothing and proportions, well suited to the different offices can be more mechanical; nothing, however sub- which the limbs have to execute. The cup or servient to the safety, less capable of being gene- socket at the shoulder is much shallower and flatrated by the action of the joint. I would particu- ter than it is at the hip, and is also in part formed larly solicit the reader's attention to this provision, of cartilage set round the rim of the cup. The as it is found in the head of the thigh-bone ; to socket, into which the head of the thigh-bone is its strength, its structure, and its use. It is an inserted, is deeper, and made of more solid mainstance upon which I lay my hand. One single terials. This agrees with the duties assigned to fact, weighed by a mind in earnest, leaves often- each part. The arm is an instrument of motion, times the deepest impression. For the purpose of principally, if not solely. Accordingly the shaladdressing different understandings and different lowness of the socket at the shoulder, and the apprehensions,-for the purpose of sentiment, for yieldingness of the cartilaginous substance with the purpose of exciting admiration of the Creator's which its edge is set round, and which, in fact, works, we diversify our views, we multiply ex-composes a considerable part of its concavity, are amples; but for the purpose of strict argument, excellently adapted for the allowance of a free moone clear instance is sufficient; and not only suf- tion and a wide range; both which the arm wants. ficient, but capable perhaps of generating a firmer Whereas, the lower limb, forming a part of the assurance than what can arise from a divided at- column of the body; having to support the boly, tention.
as well as to be the means of its locomotion ; firmThe ginglymus, or hinge-joint, does not, it is ness was to be consulted, as well as action. With manifest, admit of a ligament of the same kind a capacity for motion in all directions, indeed, as with that of the ball and socket-joint, but it is al at the shoulder, but not in any direction to the ways fortified by the species of ligament of which same extent as in the arm, was to be united stait does admit. The strong, firm, investing mem- bility, or resistance to dislocation. Hence the brane, above described, accompanies it in every deeper excavation of the socket; and the presence part: and in particular joints, this membrane, of a less proportion of cartilage upon the edge. which is properly a ligament, is considerably The suppleness and pliability of the joints, we stronger on the sides than either before or behind, every moment experience; and the firmness of in order that the convexities may play true in animal articulation, the property we have hitherto their concavities, and not be subject to slip side- been considering, may be judged of from this sinways, which is the chief danger; for the muscu- gle observation, that, at any given moment of lar tendons generally restrain the parts from go- time, there are millions of animal joints in coming farther than they ought to go in the plane of plete repair and use, for one that is dislocated; their motion. In the knee, which is a joint of and this, notwithstanding the contortions and this form, and of great importance, there are su- wrenches to which the limbs of animals are conperadded to the common provisions for the sta- tinually subject. bility of the joint, two strong ligaments which II. The joints, or rather the ends of the bones cross each other; and cross each other in such a i which form them, display also, in their configuras manner, as to secure the joint from being dis- tion, another use. The nerves, blood vessels, and placed in any assignable direction. “I think," tendons, which are necessary to the life, or for the says Cheselden," that the knee cannot be com- motion, of the limbs, must, it is evident, in their pletely dislocated without breaking the cross liga- way from the trunk of the body to the place of ments.”* We can hardly help comparing this with their destination, travel over the moveable joints;
and it is no less evident, that, in this part of their * Cies. Anat. ed. 7th. p. 45.
course, they will have, from sudden motions and
from abrupt changes of curvature, to encounter, The cartilages of which we speak, have very much the danger of comprehension, attrition, or lacera- of the form of these rings. The comparison moretion. To guard fibres so tender against conse- over shows the reason why we find them in the quences so injurious, their path is in those parts knees rather than in other joints. It is an expeprotected with peculiar care; and that by a provi- dient, we have seen, which a mechanic resorts to, sion, in the figure of the bones themselves. The only when some strong and heavy work is to be nerves which supply the fore-arm, especially the done. So here the thigh-hone has to achieve its inferior cubital nerves, are at the elbow conducted, motion at the knee, with the whole weight of the by a kind of covered way, between the condyls, or body pressing upon it, and often, as in rising from rather under the inner extuberances of the bone our seat, with the whole weight of the body to which composes the upper part of the arm.* At list. It should seem, also, from Cheselden's acthe knee, the extremity of the thigh-bone is di- count, that the slipping and sliding of the loose vided by a sinus or clitř into two heads or protu- cartilages, though it be probably a small and obberances: and these heads on the back part stand scure change, humoured the motion of the end of out beyond the cylinder of the bone. Through the thigh-bone, under the particular contiguration the hollow, which lies between the hind parts of which was necessary to be given to it for the comthese two heads, that is to say, under the ham, modious action of the tendons; (and which conbetween the ham-strings, and within the concave figuration requires what he calls a variable socket, recess of the bone formed by the extuberances on that is, a concavity, the lines of which assume a each side; in a word, along a defile between rocks, different curvature in different inclinations of the pass the great vessels and nerves which go to the bones.). leg. Who led these vessels by a road so defended V. We have now done with the configuration: and secured ? In the joint at the shoulder, in the but there is also in the joints, and that common to euge the cup which receives the head of the bone, them all, another exquisite provision, manifestly is a notch, which is joined or covered at the top adapted to their use, and concerning which there with a ligament. Through this hole, thus guard- can, I think, be no dispute, namely, the regular ed, the blood-vessels steal to their destination in supply of a mucilage, more emollient and slippery the arm, instead of mounting over the edge of the than oil itself, which is constantly softening and concavity. I
lubricating the parts that rub upon each other, and III. In all joints, the ends of the bones, which thereby diminishing the effect of attrition in the work against each other, are tipped with gristle. highest possible degree. For the continual seIn the ball and socket-joint, the cup is lined, and cretion of this important liniment, and for the the ball capped with it. The smooth surface, the feeding of the cavities of the joint with it, glands elastic and unfriable nature of cartilage, render its are fixed near each joint; the excretory ducts of of all substances the most proper for the place and which glands, dripping with their balsamic conpurpose. I should, therefore, have pointed this tents, hang loose like fringes within the cavity of out amongst the foremost of the provisions which the joints. A late improvement in what are called have been made in the joints for the facilitating of friction-wheels, which consist of a mechanism so their action, had it not been alleged, that cartilage, ordered, as to be regularly dropping oil into a box, in truth, is only nascent or imperfect bone; and which encloses the axis, the nave, and certain that the bone in these places is kept soft and im- balls upon which the nave revolves, may be said, perfect, in consequence of a more complete and in some sort, to represent the contrivance in the rigid ossification being prevented from taking animal joint; with this superiority, however, on place by the continual motion and rubbing of the the part of the joint, viz. that here, the oil is not surfaces: which being so, what we represent as a only dropped, but made. designed advantage, is an unavoidable effect. I In considering the joints, there is nothing, peram far from being convinced that this is a true ac- haps, which ought to move our gratitude more count of the fact ; or that, if it were so, it answers than the reflection, how well they wear. A limb the argument. To me, the surmounting of the shall swing upon its hinge, or play in its socket, ends of the bones with gristle, looks more like a many hundred times in an hour, for sixty years plating with a different metal, than like the same together, without diminution of its agility: which metal kept in a different state by the action to is a long time for any thing to last ; for any thing which it is exposed. At all events, we have a so much worked and exercised as the joints are. a great particular benefit, though arising from a This durability I should attribute, in part, to the general constitution: but this last not being quite provision which is made for the preventing of what my argument requires, lest I should seem wear and tear, first, by the polish of the cartilagi. by applying the instance to over-rate its value, 1 nous surfaces; secondly, by the healing lubrication have thought it fair to state the question which at- of the mucilage; and, in part, to that astonishing tends it.
property of animal constitutions, assimilation, by IV. In some joints, very particularly in the which, in every portion of the body, let it consist knees, there are loose cartilages or gristles between of what it will, substance is restored, and waste the bones, and within the joint, so that the ends repaired. of the bones, instead of working upon one another, Moveable joints, I think, compose the curiosity work upon the intermediate cartilages. Chesel- of bones; but their union, even where no motion den has observed,s that the contrivance of a loose is intended or wanted, carries marks of mecharing is practised by mechanics, where the friction nism and of mechanical wisdom. The teeth, espeof the joints of any of their machines is great; as cially the front teeth, are one bone fixed in anobetween the parts of crook-hinges of large gates, ther, like a peg driven into a board. The sutures or under the head of the male screw of large vices of the skull are like the edges of two saws clapped
together, in such a manner as that the teeth of Ches. Anat. p. 255. ed. 7. Ib. p. 35.
one enter the intervals of the other. We have 1 lh. p. 30.
§ Ib. p. 13. sometiines one bone lapping over another, and
planed down at the edges : sometimes also the thin great defect in the articulation : for the joint in lamella of one bone received into a narrow furrow the neck, although admirably adapted to the mo of another. In all which varieties, we seem to tion of the head, is insufficient for its support. It discover the same design, viz. firmness of juncture, is not only by the means of a most curious strucwithout clumsiness in the seam.
ture of the bones that a man turns his head, but by virtue of an adjusted muscular power, that he even holds it up.
As another example of what we are illustrating, CHAPTER IX.
viz. conformity of use between the bones and the
muscles, it has been observed of the different verOf the Muscles.
tebræ, that their processes are exactly proportioned
to the quantity of motion which the other bones Musches, with their tendons, are the instru- allow of, and which the respective muscles are ments by which animal motion is performed. It capable of producing. will be our business to point out instances in II. A muscle acts only by contraction. Its which, and properties with respect to which, the force is exerted in no other way. When the exdisposition of these muscles is as strictly mechani-ertion ceases, it relaxes itself, that is, it returns by cal, as that of the wires and strings of a puppet. relaxation to its former state, but without energy.
I. We may observe, what I believe is universal, This is the nature of the muscular fibre; and an exact relation between the joint and the mus- being so, it is evident that the reciprocal energetic cles which move it. Whatever motion the joint, motion of the limbs, by which we mean motion by its mechanical construction, is capable of per- with force in opposite directions, can only be pro forming, that motion, the annexed muscles, by duced by the instrumentality of opposite or antatheir position, are capable of producing. For ex-gonist muscles; of flexors and extensors answering ample; if there be, as at the knee and elbow, a to each other. For instance, the biceps and brahinge-joint, capable of motion only in the same chiæus internus muscles placed in the front part plane, the leaders, as they are called, i. e. the of the upper arm, by their contraction, bend the muscular tendons, are placed in directions parallel elbow; and with such degree of force, as the to the bone, so as, by the contraction or relaxation case requires, or the strength admits of. The reof the muscles to which they belong, to produce laxation of these muscles, after the effort, would that motion and no other. If these joints were merely let the fore-arm drop down. For the back capable of a freer motion, there are no muscles to stroke, therefore, and that the arm may not only produce it. Whereas at the shoulder and the hip, bend at the elbow, but also extend and straighten where the ball and socket-joint allows by its con- itself, with force, other muscles, the longus and struction of a rotatory or weeping motion, ten- brevis brachiæus externus and the anconæus, dons are placed in such a position, and pull in placed on the hinder part of the arms, by their consuch a direction, as to produce the motion of which tractile twitch fetch back the fore-arm into a the joint admits. For instance, the sartorius or straight line with the cubit, with no less force tailor's muscle, rising from the spine, running di-than that with which it was bent out of it. The agonally across the thigh, and taking hold of the same thing obtains in all the limbs, and in every inside of the main bone of the leg, a little below moveable part of the body. A finger is not bent the knee, enables us, by its contraction, to throw and straightened, without the contraction of two one leg and thigh over the other; giving effect, muscles taking place. It is evident, therefore, that at the same time, to the ball and socket-joint at the animal functions require that particular dispo the hip, and the hinge-joint at the knee. There sition of the muscles which we describe by the is, as we have seen, a specific mechanism in the name of antagonist muscles. And they are acbones, for the rotatory motions of the head and cordingly so disposed. Every muscle is provided hands: there is, also, in the oblique direction of with an adversary. They act, like two sawyers the muscles belonging to them, a specific provision in a pit, by an opposite pull: and nothing surely for the putting of this mechanism of the bones can more strongly indicate design and attention into action. And mark the consent of uses. The to an end, than their being thus stationed, than oblique muscles would have been inefficient with this collocation. The nature of the muscular fibre out that particular articulation : that particular being what it is, the purposes of the animal could articulation would have been lost, without the ob- be answered by no other. And not only the calique muscles. It may be proper however to ob-pacity for motion, but the aspect and symmetry of serve, with respect to the head, although I think the body, is preserved by the muscles being marit does not vary the case, that its oblique motions shalled according to this order; e.g. the mouth is and inclinations are often motions in a diagonal, holden in the middle of the face, and its angles produced by the joint action of muscles lying in kept in a state of exact correspondency, by iwo straight directions. But whether the pull be sin- muscles drawing against, and balancing each other. gle or combined, the articulation is always such, In a hemiplegia, when the muscle on one side is as to be capable of obeying the action of the mus- weakened, the muscle on the other side draws the cles. The oblique muscles attached to the head, mouth awry. are likewise so disposed, as to be capable of stea III. Another property of the muscles, which dying the globe, as well as of moving it. The could only be the result of care, is, their being alhead of a new-born infant is often obliged to be most universally so disposed, as not to obstruct or filleted up. After death, the head drops and rolls interfere with one another's action. I know but in every direction. So that it is by the equilibre one instance in which this impediment is perceived. of the muscles, by the aid of a considerable and we cannot easily swallow whilst we gape. This, equipollent muscular force in constant exertion, I understand, is owing to the muscles employed that the head maintains its erect posture. The in the act of deglutition being so implicated with muscles here supply what would otherwise be a the muscles of the lower jaw, that, whilst these
last are contracted, the former cannot act with repeated-how many mings intot go right for us freedom. The obstruction is, in this instance, to be ar hour at ease! how many more for us to attended with little inconveniency; but it shows be vigorous and active! Yet vigour and activity what the effect is where it does exist; and what are, in a vast plurality of instances, preserved in loss of faculty there would be if it were more fre- human bodies, notwithstanding that they depend quent. Now when we reflect upon the number upon so great a number of instruments of motion, of muscles, not fewer than four hundred and and notwithstanding that the defect or disorder forty-six in the human body, known and named, * sometimes of a very small instrument, of a single how contiguous they lie to each other, in layers, pair, for instance, out of the four hundred and as it were, over one another, crossing one another, forty-six muscles which are employed, may be sometimes imbedded in one another, sometimes attended with grievous inconveniency. There is perforating one another; an arrangement, which piety and good sense in the following observation, leaves to each its liberty, and its full play, must taken out of the Religious Philosopher: "With necessarily require meditation and counsel. much compassion,” says this writer, "as well as
IV. The following is oftentimes the case with astonishment at the goodness of our loving Crethe muscles. Their action is wanted, where their ator, have I considered the sad state of a certain situation would be inconvenient. In which case, gentleman, who, as to the rest, was in pretty good the body of the muscle is placed in some commo- health, but only wanted the use of these two litdious position at a distance, and made to commu- tle muscles that serve to lift up the eyelids, and so nicate with the point of action, by slender strings had almost lost the use of his sight, being forced, or wires. If the muscles which move the fingers as long as this defect lasted, to shove up his eyehad been placed in the palm or back of the hand, lids every moment with his own hands!"-In they would have swelled that part to an awkward general we may remark in how small a degree and clumsy thickness. The beauty, the propor- those, who enjoy the perfect use of their organs, tions of the part, would have been destroyed. know the comprehensiveness of the blessing, the
They are therefore disposed in the arm, and even variety of their obligation. They perceive a reup to the elbow; and act by long tendons, strapped sult, but they think little of the multitude of condown at the wrist, and passing under the liga-currences and rectitudes which go to form it. ments to the fingers, and to the joints of the fingers, Beside these observations, which belong to the which they are severally to move. In like man- muscular organ as such, we may notice some adner, the muscles which move the toes, and many vantages of structure which are more conspicuous of the joints of the foot, how gracefully are they in muscles of a certain class or description than disposed in the calf of the leg, instead of forming in others. Thus: an unwieldy tumefaction in the foot itself? The 1. The variety, quickness, and precision, of observation may be repeated of the muscle which which muscular motion is capable, are seen, I draws the nictitating membrane over the eye; think, in no part so remarkably as in the tongue. its office is in the front of the eye ; but its body is It is worth any man's while to watch the agility lodged in the back part of the globe, where it lies of his tongue; the wonderful promptitude with safe, and where it encumbers nothing.
which it executes changes of position, and the V. The great mechanical variety of the figure perfect exactness. Each syllable of articulated of the muse les may be thus stated.' It appears to sound requires for its utterance a specific action be a fixed law, that the contraction of a muscle of the tongue and of the parts adjacent to it. The shall be towards its centre. Therefore the subject disposition and configuration of the mouth, apperfor mechanism on each occasion is, so to modify taining to every letter and word, is not only pecuthe figure, and adjust the position of the muscle, liar, but, if nicely and accurately attended to, peras to produce the motion required, agreeably with ceptible to the sight; in so much, that curious this law. This can only be done by giving to persons have availed themselves of this circumdifferent muscles a diversity of configuration, stance to teach the deaf to speak, and to undersuited to their several offices, and to their situation stand what is said by others. In the same person, with respect to the work which they have to per- and after his habit of speaking is formed, one, and forin. On which account we find them under a only one, position of the parts, will produce a multiplicity of forms and attitudes ; sometimes given articulate sound correctly. How instantawith double, sometimes with treble tendons, some neously are these positions assumed and dismisstimes with none : sometimes one tendon to seve- ed; how numerous are the permutations, how ral muscles, at other times one muscle to several various, yet how infallible! Arbitrary and antic tendons. The shape of the organ is susceptible variety is not the thing we admire ; but variety of an incalculable variety, whilst the original pro- obeying a rule, conducing to an effect, and comperty of the muscle, the law and line of its con-mensurate with exigencies infinitely diversified. I Traction, remains the same, and is simple. Herein believe also that the anatomy of the tongue corthe muscular system may be said to bear a perfect responds with these observations upon its activity: resemblance to our works of art. An artist doesThe muscles of the tongue are so numerous, and not alter the native quality of his materials, or so implicated with one another, that they cannot their laws of action. He takes these as he finds be traced by the nicest dissection; nevertheless, them. His skill and ingenuity are employed in (which is a great perfection of the organ,) neither turning them, such as they are, to his account, the number, nor the complexity, nor what might by giving to the parts of his machine a form and seem to be the entanglement of its fibres, in any relation, in which these unalterable properties wise impede its motion, or render the determinamay operate to the production of the effects in- tion or success of its efforts uncertain. tended. VI. The ejaculations can never too often be
I HERE entreat the reader's permission to step a * Keill's Anatomy, p. 295. ed. 3.
little out of my way, to consider the parts of the