Imatges de pągina

ilar glistening covering of the ball or head cles to act more advantageouslv, by inof the thigh-bone, and the lubricating creasing the distance of the rope from the synovia poured into the cavity by appro- centre of motion. The patella is, morepriate secretories, and the strong liga- over, a sort of shield or protection to the ments giving strength all around, we feel fore part of this important joint. The how far the most perfect of man's works leg below the knee, like the fore-arm alfalls short of the mechanism displayed by "ready described, has two bones. They nature.

offer spacious surface of origin for the The thigh-bone is remarkable for its numerous muscles required for the feet, projections called trochanters, to which and they form a compound pillar of ine moving muscles are fixed, and which greater strength than the same quantity lengthen considerably the lever by which of bone as one shaft would have had. the muscles work. The shaft of the bone The individual bones also are angular is not straight, but has a considerable for- instead of round, hence deriving greater ward curvature. Short-sightedness might power to resist blows, &c. suppose this a weakness, because the The ankle-joint is a perfect hinge of bone is a pillar supporting a weight; but great strength. There is in front of it an the bend gives it, in reality, the strength annular ligament, by which the greater of the arch, to bear the action of the mass part of the tendons, passing downwards of muscle called vastus, which lies and io the foot and toes, are kept in ther swells upon its fore part.

places. One of these tendons passes The knee is a hinge joint of complicated der the bony projection of the inner ankle, structure; and it claims the most atten- in a smooth appropriate groove, exactly tive study of the surgeon. The rubbing as if a little fixed pulley were there. parts are flat and shallow, and therefore The heel, by projecting so far backthe joint has little strength from form; wards, is a lever for the strong muscles to but it derives security from the numerous act by, which form the calf of the bez. and singularly-strong ligaments which and terminate in the tendo achillis. These surround it. The ligaments on the inside muscles, by drawing at it, lift the body, in of the knees resemble, in two circum- the actions of standing on the toes, walkstances, the annular ligaments of joints, ing, dancing, &c. In the foot of the nenamely, in having a constant and great gro, the heel is so long as to be ugly strain to bear, and yet in becoming in European estimation ; and, its gres stronger always as the strain increases. length rendering the effort of smaller The line of the leg, even in the most per- muscles sufficient for the various purfect shapes, bends inward a little at the poses, the calf of the leg in the negro knee, requiring the support of the liga- smaller in proportion than in other races ments, and, in many persons, it bends of men. very much; but the inclination does not The arch of the foot is to be noticed as increase with age. The legs of many another of the many provisions for saving weakly in-kneed children become straight the body from shocks by the elasticity of by exercise alone. This inclination at the supports. The heels and the balls the middle joint of the leg, by throwing a of the toes are the two extremes of the certain strain on the ligaments, gives an elastic arch, and the leg rests between increase of elasticity to the limb, in the them. actions of jumping, running, &c. In the Connected with elasticity, it is interes.. knee, there is a singular provision of loose ing to remark how imperfectly a wooden cartilages, which have been called friction leg answers the purpose of a natural leg. cartilages, from a supposed relation in With the wooden leg, which always reme use to friction wheels; but their real mains of the same length, the centre of effect seems to be to accommodate, in the the body must describe, at each step, a different positions of the joint, the sur- portion of a circle of which the bottom faces of the rubbing bones to each other. nob of the leg is the centre, and the body

The great muscles on the fore part of is therefore constantly rising and fallung: the thigh are contracted into a tendon a while, with the natural legs, which, by little above the knee, and have to pass gentle flexure at the knee, are made over, and, in front of the knee, to reach shorter or longer in different parts of the the top of the leg, where their attachment step, as required, the body is carried sloeg is. The tendon, in passing over the joint, in a manner perfectly level. In like masbecomes bony, and forms the patella, or ner, a man riding on horseback, if he keep knee-pan, often called the pulley of the his back upright and stiff, has his head knee. This peculiarity enables the mus- jolted by every step of the trotting animal;

but the experienced horseman, even with- themselves, at convenient distances, to a out rising in the stirrups, by letting the strong cord called a tendon, by means of back yield a little at each movement, as a which, like a hundred sailors at a rope, bent spring yields during the motion of a they make their effort effective at any carriage, can carry his head quite smooth- distance. The tendons are remarkable ly along.

for the great strength which resides in In a general review of the skeleton, we their slender forms, and for the lubricated have to remark, 1. the nice adaptation of smoothness of their surfaces. Many other all the parts to each other, and to the striking particulars might be enumerated; strains which they have respectively to but these may suffice. Such, then, is bear; as in the size of the spinal verte- the skeleton, or general frame-work of bree increasing from above downwards; the human body-less curious and comthe bones of the leg being larger than plicated, perhaps, than some other parts those of the arm, and so on. 2. The ob- of the system, but so perfect and so wonjects of strength and lightness combined; derful, that the mind which can attenas by the hollowness of the long bones; tively consider it without emotion, is in a their angular form; their thickening and state not to be envied. flexures in particular places where great The living force of man has been used strain has to be borne; the enlargement of as a working power in various ways, as the extremities to which the muscles are in turning a winch, pulling at a rope, attached, lengthening the lever by which walking in the inside of a large wheel to chese act, &c. 3. We have to remark move it, as a squirrel or turn-spit dog the nature and strength of material in moves his little wheel, &c. Each of different parts, so admirably adapted to the these has some particular advantage ; but purposes which the parts serve. There is that mode in which, for many purposes, a bone, for instance, in one place, nearly as the greatest effect may be produced, is bard as iron, where, covered with enamel, for the man to carry up to a height his it has the form of teeth, with the office of body only, and then to let it work by its chewing and tearing all kinds of matter weight in descending. A bricklayer's used as food. In the cranium,again, bone laborer would be able to lift twice as is softer, but tough and resisting; in the many bricks to the top of a house in the middle of long bones, it is compact and course of a day, by ascending a ladder little bulky, to leave room for the swelling without a load, and raising bricks of of the muscles lying there ; while, at either nearly bis own weight over a pulley each end, it is large and spongy, with the same time in descending, as he can by carrying quantity of matter, to give a broad sur- bricks and himself up together, and deface for articulation; and, in the spine, scending again without a load, as is still the bodies of the vertebræe, which rest on usually done. an elastic bed of intervertebral substance,

Reflection would naturally anticipate are light and spongy, while their articu- the above result, independently of exlating surfaces and processes are very hard. periment; for the load which a man In the joints, we see the tough, elastic, should be best able to carry, is surely that smooth substance, called cartilage, cover- from which he can never free himselfing the ends of the bones, defending and the load of his owu body. Accordingly, padding them, and destroying friction. In the strength of muscles and disposition infants, we find all the bones soft or gristly, of parts are all such as to make his body and therefore calculated to bear, with appear light to him. impunity, the falls and blows unavoidable The question which was agitated with at their age; and we see certain parts such warmth some time ago, as to the remaining cartilage or gristie for life, propriety of making men and women where their elasticity is necessary or use- work on the tread-mill, receives an easy tul, as at the anterior extremities of the decision here. They work by climbing ribe. About the joints, we have to re- on the outside of a large wheel or cylininark the ligaments which bind the bones der, which is turning by their weight, and together, possessing a tenacity scarcely on which they must advance just as fast equalled in any other known substance; as it turns, to avoid falling from their and we see that the muscular fibres, whose proper situation. There are projections contractions move the bones, and thereby or steps for the feet on the outside of the the body,–because they would have cylinder, and the action to the workers is made the limbs clumsy even to deformity exactly that of ascending an acclivity. had they all passed over the joints to the Now, as nature has fitted the human boriy parts which they have to pull,—attach for climbing hills, as well as for walking


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on plains, the work of the tread-mill, un- same, to open the body; burt sir Hudson der proper restrictions as to duration, Lowe would not permit it. After his re must be as natural and healthful as any turn to Europe, he published, in 1825, in other. Its effects have now proved it to Paris, a description of Napoleon's last bo be so.

ments. This work, as well as those of As animal power is exhausted exactly O'Meara and Las Cases, are importan in proportion to the time during which it contributions to the history of the empe is acting, as well as in proportion to the ror. Antommarchi afterwards pracused intensity of force exerted, there may often medicine in Paris, and completed in be a great saving of it by doing work beautiful but very expensive anatomica quickly, although with a little more exer- plates, which he had previously comtion during the time. Suppose two men menced with Morgagni in Florence. of equal weight to ascend the same stair, When Poland was visited by the horror one of whom takes only a minute tó of war, he hastened thither, leaving he reach the top, and the other takes four lucrative practice and scientific labors. minutes ; it will cost the first but a little With considerable trouble he reache. more than à fourth part of the fatigue Warsaw, where the national governors which it costs the second, because the gave him the direction of the medica exhaustion has relation to the time during establishments. Still more difficulties which the muscles are acting. The were thrown in his way on his returi quick mover may have exerted, perhaps, from Poland, especially in Hesse-Casse, one twentieth more force in the first in- ostensibly on account of his coming fron stant, to give his body the greater velocity a country infested with cholera, but in re which was afterwards continued ; but the ality on account of his political principles. sloth supported his load four times as After his return to Paris, he was near bir long.

ing sent by Périer to Avignon with the Å healthy man will run rapidly up a Poles. Towards the end of 1831, he kti long stair, and his breathing will scarcely Paris and went to Italy. He possesses a be quickened at the top; but, if he walk plaster cast of Napoleon, made from a up slowly, his legs will feel fatigued, and mask taken immediately after his death. he will have to wait some time before he Aphides, or VinE-FRETTERS. (Se can speak calmly.

For the same reason, coach-horses are APLOME. (See Garnet.) much spared by being made to gallop up ARBALIST. (See Cross-Bou.) a short hill, and being then allowed to go ARBORIZATIONS. (See Dendrites.) more slowly for a little time, so as to rest ARCOPOLIS. (See Little Rock.) at the top.

ARCTIC SEAS. (See Morth Polar ErThe rapid waste of muscular strength, peditions.) which arises from continued action, is ARGENTINE REPUBLIC. An account shown by keeping the arm extended hor- of this state will be found under the best izontally for some time: few can continue of Plata, United Provinces of the. the exertion beyond a minute or two. In ARQUEBUSs. (See Harquebuss.) animals which have long horizontal ARROW-HEAD CHARACTER. (See Pornecks, there is a provision of nature in a sepolis, and Writing.) strong elastic substance on the back, or ARTIGAS. We have to add to the arupper part of the neck, which nearly sup- count given of this general, that he was ports the head, independently of muscular retained prisoner by doctor Francia, who exertion.

treated him, at the same time, with great ANISETTE. (See Liqueur.)

kindness, and provided for his comitortaAxxotta. (See Arnatto.)

ble support. He died in 1820. Anspach, MARGRAVINE OF. (See Cra- ARUNDEL, EARL OF. (See Howard, ren, Lady.)

Antioch, Era of. (See Epoch.) ARZERUM. (See Erzeruin.)

ANTOMMARCHI; physician of Napoleon Ascites. (See Dropsy.) at St. Helena. He is a native of Corsica, Ashburtox, LORD. (See Dunning.) who left a professorship of anatomy in Assa. (See Esneh.) Florence, in order to attend the exiled Astana (asthma, Latin; from isso emperor. Cardinal Fesch offered him a to breathe with difficulty); dithculty of pension ; but he refused it. He attended respiration, returning at intervals, with the emperor till his last moments; and a a sense of stricture across the brees legacy of 100,000 francs was let him in and in the lungs a wheezing, hard his will. He was also charged, in the cough, at first, but more free towards the


close of each paroxysm, with a discharge to time throughout the day; and, the disof mucus, followed by a remission. ease going off at last, the patient enjoys Asthma rarely appears before the age of pu- his usual rest by night, without further berty, and seems to attack men more fre- disturbance. The exciting causes are quently than women, particularly those various :-accumulation of blood or viscid of a füll habit, in whom it never fails, by mucus in the lungs, noxious vapors, a frequent repetition, to occasion some de- cold and foggy atmosphere, or a close, gree of emaciation. In some instances, hot air, the repulsion of eruptions, or othit arises from a hereditary predisposition; er metastatic diseases, flatulence, accuand in many others, it seems to depend mulated feces, violent passions, organic upon a particular constitution of the diseases in the thoracic viscera, &c. Jungs. Dyspepsia always prevails, and sometimes the fits return at pretty regular appears to be a very prominent feature in periods; and it is generally difficult to obthe predisposition. Its attacks are most viate future attacks, when it bas once ocfrequent during the heats of summer, in curred: but it often continues to recur the dog-days, and in general commence for many years, and seldom proves fatal, about midnight. On the evening preced- except as inducing bydrothorax, phthisis, ing an attack of asthma, the spirits are &c. The treatment must vary according often much affected, and the person ex- to the form of the disease. By far the periences a sense of fulness about the most important part of the treatment constomach, with lassitude, drowsiness, and sists in obviating or removing the several a pain in the head. On the approach of exciting causes, whether operating on the the succeeding evening, he perceives a lungs immediately, or through the medisense of tightness and stricture across the um of the primæ viæ, &c. Individual breast, and a sense of straitness in the lungs, experience can alone ascertain what state impeding respiration. The difficulty of of the atmosphere, as to temperature, drybreathing continuing to increase for some ness, purity, &c., is most beneficial to length of time, both inspiration and expi- asthmatics, though a good deal depends ration are performed slowly, and with a on habit in this respect; but a due reguwheezing noise; the speech becomes dif- lation of this, as well as of the diet, and ficult and uneasy; a propensity to cough- other parts of regimen, will usually afford ing succeeds, and the patient can no longer more permanent relief than any mediremain in a horizontal position, being as cines we can employ. it were threatened with immediate suffo- ASTROMETER. (See Heliometer.) cation. These symptoms usually con- Atomic Theory, in chemistry. Two tinue till towards the approach of morn- opposite opinions have long existed coning, and then a remission commonly cerning the ultimate elements of matter. takes place; the breathing becomes less It is supposed, according to one party, laborious and more full, and the person that every particle of matter, howevspeaks and coughs with greater ease. If er small, may be divided into smaller the cough is attended with an expectora- portions, provided our instruments and tion of mucus, he experiences much re- organs were adapted to the operation. lief, and soon falls asleep. When he Their ponents contend, on the other awakes in the morning, he still feels band, that matter is composed of certain some degree of tightness across his breast, atoms, which are of such a nature as not although his breathing is probably more to admit of further division. These opfree and easy, and the least motion ren- posite opinions have, from time to time, ders this more difficult and uneasy; nei- been keenly contested, and with variable ther can he continue in bed, unless his success, according to the acuteness or inbead and shoulders are raised to a con- genuity of their respective champions. siderable height. Towards evening, he But it was at last perceived that no posiagain becomes drowsy, is much troubled tive data existed capable of deciding the with flatulency in the stomach, and question; and its interest, therefore, graduperceives a return of the difficulty of ally declined. The progress of modern breathing, which continues to increase chemistry has revived the general attengradually, till it becomes as violent as tion to this controversy, by affording a far on the night before. After some nights stronger argument in favor of the atomic passed in this way, the fits at length constitution of bodies than was ever admoderate, and suffer more considerable vanced before, and which seems almost remissions, particularly when they are at- irresistible. We have only, in fact, to astended by a copious expectoration in the sume, with Mr. Dalton, that all bodies are mornings; and this continues from time composed of ultimate atoms, the weight


of which is different in different kinds others, it should be held in mind that it of matter, and we explain at once va- merely denotes the proportions in which rious laws of chemical union. Accord- bodies unite; that it is the expressiou or ing to this view, every compound is form- a fact which will remain the same, wheth. ed by a combination of the atoms of its er the atomic hypothesis which suggestconstituents. An atom of A may com- ed the employment of the term be true bine with 1, 2, 3, or more atoms of B-an or false. There is one circumstaner arrangement on which depends the law which, at the first view, seems hostile to of multiples. If water, for example, is the supposed atomic constitution of mar. composed of an atom of hydrogen and ter. According to the law of multian atom of oxygen, it follows that every ples (see Chemical Equivalents ), oxygen compound of hydrogen with an additional in the three oxides of lead is in the rais) quantity of oxygen, must contain 2, 3, or of 1:19 : 2 ; so that, if we regard there more atoms of oxygen; some multiple in protoxide as composed of one combining a word by a whole number of the quan- proportion of lead to one proportion of tity of oxygen contained in water. "It is oxygen, the second will contain one proequally clear, from this view of the com- portion and a half, or, according to the position of water, that the weight of an atomic theory, one atom and a half of oxatom of oxygen is eight times heavier ygen. Now, though the half of a comthan an atom of hydrogen. The relative bining proportion may be admitted, the weight of the atoms of other substances existence of half an indivisible particle may be determined in a similar manner. of matter is inconceivable; and this cirThus an atom of carbon is 6 times, an cumstance would be fatal to the atomic atom of sulphur 16 times, and an atom of theory, were there not some satisfactory chlorine 36 times, heavier than an atom mode of accounting for it. Several exof hydrogen; and this explains why they planations might be brought forwani. unite with one another in the proportions One of them, which has found its advoexpressed by those numbers. What are cates, rests on the supposition that what called the proportional numbers are, in is called the protoxide, is, in reality, comfact, nothing else but the relative weights posed of one atom of lead to two atoms of atoms. No one can suppose that the of oxygen ; and that the real protoxide laws of chemical union are the effect of has not yet been discovered. Another chance: there must be some cause for mode of accounting for the anomaly them in the nature of the ultimate parti- by regarding the present deutoxide cles of matter. This cause, as we have composed of the protoxide and perorate just seen, is completely supplied by the combined with each other. A third methsupposed atomic constitution of bodies, od is, by doubling both elements of the which accounts for the phenomena in the anomalous compound, by which the exact most beautiful and consistent manner. ratio is preserved, and the idea of the So perfect, indeed, is the explanation, that fraction of an atom is avoided. Thus the the existence of these laws might have protoxide and peroxide of iron are colbeen predicted by the aid of the atomic posed, the first, of one proportion, or hypothesis long before they were actually of metal + 8 of oxygen, and the second, discovered by analysis. But these are of 28 of metal + an atom and a half, or not the only arguments which we at pres- 12 of oxygen ; or, what amounts to the ent possess in favor of the existence of same thing, of 56, or two atoms of iron, ultimate indivisible particles of matter. to 24, or three atoms of oxygen. These Doctor Wollaston, in his paper on the observations prove, that the occurrence Finite Extent of the Atmosphere (Philo- of half proportions is not inconsistent sophical Transactions, 1822), has defend, with the atomic constitution of boulies: ed this side of the question on a new and they show that the difficulty is explicable, independent principle; and the proof be and probably will, in the progress of dis has given of the atomic constitution of covery, be entirely removed. In the bodies appears decisive. Some chemists, mean time, however, it would be incoueven without expressly adopting the atom- venient to allow any speculative noties ic theory itself, have followed Mr. Dalton on the subject to interfere with actual in the use of the terms atom and atomic practice; and, therefore, it is best at once weight, in preference to proportion, com- to admit the occurrence of half proporbining proportion, equivalent, and others tions; and, if any one prefer the term of a like kind. All these appellations, atom to equivalent or proportion, he mus however, have the same signification ; submit to the somewhat jarring expres and, in using the word atom, instead of the sion of half an atom. Mr. Dalton sup

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