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shals" (2 vols. 12mo., New York, 1846), a work written for effect, and which has attained a great degree of popularity. It was followed in the same year by the "Sacred Mountains," and in the following year by "Washington and his Generals" (2 vols.). His melodramatic treatment of sacred subjects in the former work was much criticized. Among his later publications are lives of Oliver Cromwell, Winfield Scott, Andrew Jackson, and Washington; "Adirondack, or Life in the Woods" (1849); the "Imperial Guard of Napoleon from Marengo to Waterloo" (1852), founded on a popular French history by E. M. de St. Hilaire; a "History of the Second War between England and the United States" (2 vols., 1853); "Sacred Scenes and Characters;" and "Life of General Havelock" (1859). Mr. Headley resides near Newburg on the Hudson river. In 1854 he was elected a representative in the legislature, and in 1855 was chosen secretary of state of New York for the term of 2 years ending Dec. 31, 1857.

HEALY, GEORGE PETER ALEXANDER, an American painter, born in Boston in 1808. He went to Paris about 1836, where he remained several years, alternating his residence there with occasional visits to the United States. Among the pictures executed by him abroad are portraits of Louis Philippe, Marshal Soult, Gen. Cass, &c. At home he has painted Calhoun, Webster, Pierce, and other prominent American statesmen. He has occasionally produced large historical pictures, of which "Webster's Reply to Hayne," illustrating a well known scene in American legislative history, was completed in 1851, and now hangs in Faneuil hall in Boston. At the great exhibition of Paris in 1855 he exhibited a series of 13 portraits and a large picture representing Franklin urging the claims of the American colonies before Louis XVI., for which he received a medal of the 2d class. Of late years Mr. Healy has resided in Chicago, and among his most recent works is a portrait of President Buchanan.

HEARD, a W. co. of Ga., bordering on Ala., and intersected by the Chattahoochee river; area, 286 sq. m.; pop. in 1852, 6,955, of whom 2,329 were slaves. The surface is hilly and well wooded with oak, hickory, and pine. Gold, lead, and iron have been found, and the soil is generally rich. The productions in 1850 were 265,242 bushels of Indian corn, 35,034 of oats, 41,354 of sweet potatoes, and 3,384 bales of cotton. There were 24 churches and 403 pupils attending public schools. Value of real estate in 1856, $888,033. Capital, Franklin.

HEARING. See ACOUSTICS, and EAR. HEARNE, SAMUEL, an English explorer, born in London in 1745, died in 1792. In early life he served as a midshipman under Hood, but upon the conclusion of the 7 years' war he entered the employment of the Hudson's Bay company, at whose request he made several journeys into the northern regions of British America in quest of a N. W. passage and of mines of the precious metals. In 1770-'71 he pene

trated as far as the Coppermine river, which he descended about 30 miles to the Arctic ocean, thus determining the possibility of reaching the northern coast of America. He was promoted for these services, and in 1787 returned finally to England. In 1795 appeared his "Journey from the Prince of Wales's Fort, in Hudson's Bay, to the Northern Ocean; undertaken by order of the Hudson's Bay Company for the Discovery of Copper Mines, a North-West Passage, &c., in the Years 1769, 1770, 1771, and 1772" (4to., London).

HEARNE, THOMAS, an English antiquary and author, born at White Waltham, Berkshire, in 1678, died June 10, 1735. He was graduated at Oxford in 1699, and became janitor of the Bodleian library in 1701, and in 1712 second librarian. Three years later he was appointed architypographus of the university and esquire beadle of civil law; but being a strong Jacobite, he was soon after compelled to resign his offices, from his refusal to take the oath of allegiance to George I. Throughout his life he continued to entertain opinions hostile to the house of Hanover, and frequently introduced them irrelevantly into the prefaces to books which he edited. His plodding industry, as well as his irritable temper, brought upon him the ridicule of many contemporary satirists, and Pope has described him in the "Dunciad," under the name of "Wormius," as "in closet close ypent, . . . . on parchment scraps yfed." Among Hearne's most valuable publications, which amount to over 40, and the greater part of which were printed by subscription at Oxford, are the "Life of Elfred the Great," from Sir John Spelman's manuscript in the Bodleian library (8vo., 1709); Leland's Itinerary" (9 vols. 8vo., 1710-'12); Leland's "Collectanea" (6 vols. 8vo., 1715), &c.

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HEART, a hollow muscular organ placed in the cavity of the chest between the lungs and above the diaphragm, which separates it from the stomach. It is somewhat conical in shape, the axis of the cone being directed obliquely from its upper extremity downward and forward to the left. The base of the cone is the upper part of the heart; its apex is the lower. The great mass of the heart is behind the sternum in the middle of the chest, but the apex extends into the left side of this cavity. The upper border of the heart is just behind a line that would unite the third costal cartilages; the apex of this organ corresponds to the interspace between the cartilages of the 5th and 6th ribs, nearly 2 inches below the left nipple. In the adult, the heart is about 5 inches in length, 3 in breadth, and 2 in the antero-posterior diameter. The weight of the heart varies according to the weight of the body, and the proportion usually is nearly 1 to 170 in males and 1 to 150 in females. According to most anatomists, it averages from 10 to 12 ounces in the adult male, and from 8 to 10 in the feinale; but Bouillaud says the average weight in adults is only a little more than 8 ounces. In old

age it is larger than in middle life. The heart is essentially composed of 4 cavities or chambers; the two upper ones are the auricles, the lower ones are the ventricles. The auricles receive the blood brought by the veins to the heart, and the ventricles are the parts from which the blood is sent to the various organs. The right auricle receives the blood from the whole body except the lungs, and the left auricle the blood from the lungs. (See CIRCULATION.) In adults the two auricles have no communication with one another, but both have a large aperture of communication with the ventricles. Their walls are much thinner than those of the ventricles; they are both in continuity with the largest veins of the body. The right auricle is the larger and thinner; it is an enlargement of the two vena cava, united with the right ventricle and separated from the left auricle by a muscular wall. Many openings may be seen on the internal surface of this auricle: 1, on the posterior and inferior part, the very large opening of the inferior vena cava; 2, on the upper and front part, the superior vena cava; 3, on the posterior and lower part, the coronary sinus by which the blood returns from the substance of the heart; 4, between the right auricle and the corresponding ventricle, the auriculo-ventricular opening; 5, many minute apertures through which a number of small veins throw blood into the auricles. In the right auricle of the adult we find several parts which are vestiges of the foetal heart; for instance, the Eustachian valve, which is much diminished; the fossa oralis, usually a simple depression on the interauricular walls, where an opening exists in the foetal heart, which may remain in adults and allow a mixture of the black and the red blood. Both the right and left auricles have an appendix, the shape of which has some resemblance to a dog's ear. The muscular walls of the appendices are very thin, and their cavity is a continuation of that of the auricles. In the two appendices there are small muscular columns, some of which are cylindrical, running transversely across the inner surface of those extremities and of the adjoining parts of the auricles. These columns, called musculi pectinati, on account of their resemblance to the teeth of a comb, are more numerous and larger in the right than in the left appendix. The left auricle presents 5 openings; one is the aperture communicating with the corresponding ventricle, while the 4 others belong to the pulmonary veins. These last openings are placed very near one another, and sometimes, instead of the two by which the red blood comes from the left lung into the auricle, there is but one large aperture on account of the merging of the two left pulmonary veins. The two ventricles constitute a much larger portion of the heart than the auricles. The walls of the left ventricle are notably thicker than those of the right; and while the latter ventricle is thicker near its base than elsewhere, the left one is thicker in its middle part than at

the base or at the apex of the heart. The right ventricle is somewhat pyramidal, and the other conical. The left ventricle is longer than the right, and forms almost alone the apex of the heart. The right ventricle is often called anterior, on account of its being placed almost entirely in front of the other. In the two ventricles we have to study nearly similar parts, which are the openings, the valves, and a peculiar apparatus chiefly destined to move some of the valves. Two openings exist in each ventricle, the auriculo-ventricular and the opening of the two principal arteries of the body. The auriculo-ventricular opening is the aperture of communication between the auricles and ventricles; the larger opening belongs to the right ventricle. These two openings are nearly an inch in diameter; they are surrounded by a ring of fibrous tissue, to which are attached the valves which will be described below. In the right or anterior ventricle we find the opening of the pulmonary artery, which is in front of the auriculo-ventricular aperture, near the wall which separates the two ventricles (the septum ventriculorum). In the left ventricle is the opening of the aorta, in front and to the right of the auriculo-ventricular aperture. The semilunar valves surround the orifices of the aorta and of the pulmonary artery, in each of which they consist of 3 semicircular folds of the endocardium, the lining membrane of the cavities of the heart, with an addition of fibrous tissue. Between each valve and the corresponding part of the aorta or pulmonary artery there is a pouch due to a partial dilatation of these vessels. The valves have an upper border (the free one), which is straight, and a lower or adherent one, which is convex. The other system of valves found in the heart differs in its two ventricles; in the right one the system is composed of 3 triangular segments, and in the left of only 2; the first forms the tricuspid valve, the second the mitral valve. Both are composed of double folds of the lining membrane, with an addition of fibrous tissue, and probably of some muscular fibres. They adhere to the margin of the auriculo-ventricular opening, and give insertion by their lower surface and their free margin to a number of tendinous cords, the chorda tendinew. The disposition of the various parts of the valvular apparatus in the ventricles is such that when these two muscular pouches contract (which action is called systole), the blood tending to pass by the 4 openings pushes open the semilunar valves and escapes freely by the two arterial trunks; while, on the contrary, the tricuspid and mitral valves are pushed upward and prevent the reflux of this liquid into the auricles. The reverse takes place at the time of dilatation or diastole of the ventricles; the blood tends to return into the dilating ventricles, and pushes down the semilunar valves, which at once completely prevent its falling into the ventricles; while, on the contrary, the mitral and tricuspid valves relax. In the two ventricles a large number of muscular columns

(columnæ carnea) are found. These columns are rounded, and originate from almost all the parts of the inner surface of the ventricles, upon which they interlace in all directions. There are 3 kinds of muscular columns: 1, those which are adherent all along their length with the wall of the ventricles; 2, those which are free in their middle and adherent by their two extremities; 3, those which adhere by one extremity to the ventricular wall, and by the other are attached to tendinous cords inserted upon the auriculo-ventricular valves. The heart is covered outside by two membranes, constituting the pericardium, and lined inside of its cavities by a thin membrane, the endocardium. The pericardium consists of a strong layer of fibrous tissue attached to the fibrous part of the diaphragm and to the areolar tissue investing the large blood vessels springing from the heart. It is a membranous bag fixing the position of the heart. The inner surface of this fibrous bag is lined by a very thin membrane, which is the serous pericardium, extending also over the outer surface of the heart, which it covers entirely. The endocardium is an extremely thin membrane which lines all the cavities of the heart, and is a continuation of the inner or epithelial membrane of the blood vessels. It is composed of a superficial layer of epithelium, placed upon a delicate stratum of fine fibres of fibrous tissue. The various valves of the heart are chiefly formed by folds of this membrane.The muscular tissue of the heart presents several interesting characters. In man and the higher vertebrates it belongs essentially to the variety of striated or striped muscular fibres, but the stripes are less marked and the fibres thinner than in the muscles of animal life, and the fibres present the important peculiarity of branching and anastomosing one with another, so that the whole muscular fabric of the ventricles and that of the auricles may be considered as two complicated and inextricable networks of muscular fibres. Another peculiarity of the heart is, that there is no areolar tissue, or but little, between the fibres, while in other muscles there is a considerable quantity of this tissue between fascicles of fibres. In consequence of the interlacement of the fibres of the heart, it is very difficult to ascertain their disposition; but if, instead of trying to follow up small fascicles of fibres, we study the arrangement of large bundles or bands, we find that there are two distinct divisions of the fibres of the heart: 1, those belonging to the two ventricles or the two auricles; 2, those which belong only to one of these pouches. The bundles common to the two ventricles seem to emerge from the apex and to cover the anterior and posterior surfaces of the heart. At the base of the ventricles many of them are inserted upon the fibrous zone placed between these pouches and the auricles. At the apex of the heart these bundles partly pass inside of the walls of the heart, and partly pass obliquely from right to left on the posterior surface,

and from left to right on the anterior surface. The bundles of fibres belonging properly to but one of the ventricles are chiefly transversal and circular, so that their general direction is perpendicular to that of the fibres common to both ventricles. The bundles of fibres comon to the two auricles are transversely placed on the anterior and lateral surfaces of the auricles. The bundles belonging properly to but one auricle are circular or spiral, and they cross one another in several directions. Around nearly all the venous or other openings of the heart there are bundles of circular fibres, forming a kind of sphincter.-Two arteries, the anterior and the posterior coronary, furnish red or arterial blood to the tissue of the heart; they originate in the aorta near its origin. The veins are more numerous, as, beside the great cardiac vein, there are many smaller ones. The nerves of the heart come from two sources, the par vagum and the sympathetic. A peculiar anatomical feature of the heart is that it contains many small nervous ganglia, most of which can be seen only with the aid of a microscope.

Like all the other muscles of living animals, the heart is endowed with irritability, i. e., the power of contracting after excitation or stimulation. The heart is among the organs in which irritability lasts longest after death. It is not true, however, that, as stated by many physiologists, the heart is always the last organ to lose its vital properties. Fontana showed that the muscles of animal life (those of the limbs and trunk) often remain irritable longer than the heart; Dr. Brown-Séquard has shown that the iris, the diaphragm, and also the muscles of the limbs, very often remain much longer irritable than the heart, not only in animals but also in man. The cases of longest duration of irritability after death, in man, recorded by Nysten, are, for the heart, 16 hours, and for the muscles of the limbs, 27 hours. Carpenter, with almost all physiologists, says that the irritability of the heart is much less speedily destroyed in cold than in warm-blooded animals. This is not always true. Remak has seen irritability continue two days in the heart of birds and mammals; Brown-Séquard, from 31 to 34 hours in Guinea pigs and rabbits, and 53 hours in dogs; and M. Vulpian, 53, 57, and even more than 934 hours in dogs. So far as we know, this exceeds the greatest duration of the irritability of the heart in cold-blooded animals. Most physiologists, also, say that in newly born animals the irritability of the heart lasts longer after death than in adults. This is true only in certain circumstances, and especially when the temperature of the newly born animal has been much diminished before death. Very frequently the heart remains much longer irritable in adults than in newly born creatures.As long as life lasts the heart has movements which afford a most interesting study. We will first examine the circumstances relating to the persistence of these movements after death. In normal conditions the two auricles contract

together, and push the blood into the ventricles, which, after having been distended by this liquid, contract in their turn and force the blood into the pulmonary artery and the aorta. On account of their perfect regularity these movements are called rhythmical. Whatever be the cause of rhythmical action of the heart, it seems to be in this organ itself, as when the heart is taken out of the chest it continues to move rhythmically. Even parts of the heart separated from the rest, as shown first by Haller, continue, though but for a short time, to have rhythmical movements. The movements of the heart may persist for a long while after death. Boyle has seen them continue 7 hours, and Hooke more than 12 hours, in newly born dogs; M. Vulpian has seen the auricles of a dog moving regularly 26 hours after death, and M. Rousseau states that, in a woman decapitated at Rouen in 1808, the 4 parts of the heart had regular contractions and relaxations 29 hours after death. We feel inclined to doubt the correctness of this statement, as we find that the rhythmical movements of the ventricles, if not of the auricles, had ceased entirely in less than one or two hours in 23 decapitated men, observed by Nysten, Rochard, Brown-Séquard, Harless, Kölliker, &c. In 4 criminals, hanged in Boston and Philadelphia, the movements of the heart had stopped in much less than an hour. When the movements of the heart have ceased, it is usually possible for a time to reproduce them. Any kind of excitation, such as a puncture, a pressure, the influence of water, of acids, of alkalies, of heat, of galvanism, &c., may renew for a few minutes or a much longer time the regular contractions and relaxations of the heart. We have already said that the heart may have its rhythmical action, although separated from the body, and therefore deprived of the action of the cerebro-spinal axis. We may add that the researches of Bidder on the spinal marrow, and those of Brown-Séquard on the medulla oblongata and the rest of the encephalon, show that the extirpation of these nervous centres, in certain animals, does not necessarily cause death, and, still more, frequently allows life and therefore the movements of the heart to continue for many months, without any apparent alteration. Moreover, it is well known that the heart has regular movements during the intra-uterine life in monsters deprived of any part of the cerebro-spinal centres. It seems, therefore, that we ought to reject entirely the views of Legallois and others, who considered the spinal cord or the medulla oblongata as the source of excitation of the movements of the heart. But if those parts of the cerebro-spinal axis have not the function which was attributed to them, they have undoubtedly a very great influence upon the heart, either to stop or diminish, or to increase or disturb, its rhythmical action.-There is a peculiar influence of the nervous system upon the heart which is still insufficiently known, although it is of the

greatest importance; we mean that by which the heart's action is completely or incompletely stopped at once, and through a peculiar agency of the par vagum, one of the nerves of the heart. This stoppage of the rhythmic movements of the heart is the usual cause of death when it occurs suddenly after an emotion, after a wound (without much hæmorrhage) of the abdomen, after a blow on the cardiac region, after certain injuries to the medulla oblongata or the medulla spinalis, after drinking cold water on a warm day, after a shower bath, &c. It is in this way also that, in a few cases, chloroform has caused death. Dr. Brown-Séquard has ascertained that when the heart is stopped by this peculiar influence of the nervous system, it is usually easy to set it in action again by mechanical excitation made by pressing upon it through the walls of the chest. He has found that every effort of dilatation of the chest, in inspiration, is associated with some retardation of the heart's action. Taking notice of this fact, on the one side, and, on the other, of the most important fact that when respiration is not free the movements of the heart increase in frequency and energy, it seems quite rational to recommend, as was done empirically by an author of the last century, to stop respiration for a short time (half a minute or a little more) in cases of syncope. The nervous centres may act also upon the heart to produce an augmentation or a disturbance in the movements of this organ; but whether these modes of influence are direct or not is not yet positively decided. It is certain, however, that at least in many cases it is through a disturbance of the respiratory function that an increase or irregularities in the movements of the heart are produced. Most of the German physiologists now admit that the cause of the rhythmical movements of the heart is a peculiar influence exerted by small nervous ganglions that are found in this organ. But it seems very improbable that the rhythm of the heart's action depends upon those small ganglions. In the first place, the heart in the embryo, before the formation of the nervous system in its tissues, when even the muscular fibres are not yet formed, is composed of cells, which have regular movements; in the second place, the various veins in the neighborhood of the heart, although there is no ganglion in them, have rhythmical contractions, as was well shown by Allison of Philadelphia; in the third place, all the contractile tissues of the body, although without ganglions, may, as shown by Brown-Séquard, have rhythmical movements.-Muscular irritability in the heart, as everywhere else, seems to depend upon a peculiar influence of blood. The movements of the heart, therefore, as they are simple manifestations of the irritability of the muscular tissue of that organ, depend also upon the action of the blood. Experiments made by Erichsen show that ligatures upon the arteries of the heart are soon followed by the cessation of its movements. More decisive facts published by Brown-Séquard show that

when not only the movements but also the irritability of the heart have ceased, an injection of blood into the coronary arteries may restore both the irritability and the movements of this organ. We cannot enter here into the exposition of the principal views of the cause of the rhythmical movements of the heart, but it seems most probable that this cause consists in a peculiar change taking place in the muscular fibres of the heart, and that this change is due to the influence of certain principles existing around these fibres.-Much discussion has taken place concerning the direction of the movements of the heart. Harvey and two able American experimenters, Drs. Pennock and Moore, assert that when the ventricles contract they elongate and their apex protrudes. Most other physiologists affirm, on the contrary, that the ventricles shorten. These two statements may be reconciled; the writer has seen the ventricles shorten in dogs as long as the movements of the heart were vigorous, and elongate when they became feeble. Carpenter states that the apex of the ventricles when they contract describes a spiral curve from right to left and from behind forward. The truth is that it is from left to right that the point is directed. Harvey thought that the heart, at the time of the ventricular contraction, strikes the wall of the chest by its apex. This view is no longer admitted; almost all physiologists think that it is by the middle or the upper part of the right ventricle that the heart strikes the breast. Strange to say, it is still a debated question whether the beating takes place during the systole or contraction of the ventricles, or during their dilatation or diastole. Two sounds accompany the movements of the heart; one of these sounds, known as the first, is dull and prolonged, while the second is sharp and short. The first sound coexists with the beating of the heart and the pulsation of arteries; the second is produced a very short time after the first. The principal cause of these sounds is the sudden tension of the valves of the heart. The first sound is principally due to the sudden tension of the auriculo-ventricular valves when the ventricles contract; the second sound is chiefly due to the tension of the valves at the origin of the aorta and of the pulmonary artery. Other causes add their action to the preceding for the production of these two sounds, or of one of them; we will only mention the impulse of the heart against the wall of the chest, the muscular contraction, the collision of the particles of the blood with each other, and the friction of this liquid against the walls of the heart and against the mouth of the aorta and of the pulmonary artery. (See BLOOD, CIRCULATION, PULSE, &c.) DISEASES OF THE HEART. The heart may be affected with violent palpitation or with irregularity of action without the presence of organic disease, and it is not always easy to discriminate such cases; the absence of increased dulness over the cardiac region, of all signs of valvular affection, and the fact that the point of

the heart is felt to strike in its normal position, are our surest guides. Such cases are usually connected with undue excitability of the nervous system, with derangement of the stomach, or with the abuse of tobacco. The serous sac enveloping the heart may be inflamed, constituting pericarditis. The symptoms of this disease are frequently trifling; the most common is pain referred to the cardiac region or to the epigastrium, and extending sometimes toward the left shoulder. The pulse, often quite unaffected, may be frequent and irregular; dyspnoea is not commonly marked, though in rare cases it may become so severe that the patient is unable to assume the recumbent posture (orthopnoea). In the course of the disease lymph is effused, by which the opposite surfaces are roughened; afterward serum may be poured out, distending the sac of the pericardium. When recovery takes place, the two surfaces of the pericardium are found adherent, thus to a greater or less extent obliterating its cavity. Rheumatism and Bright's disease are the most common causes of pericarditis. Sometimes it arises from an extension of inflammation from the neighboring pleura, and it may result from external injury. For the diagnosis of pericarditis we must rely mainly on the physical signs. Early in the disease there is developed over the heart a friction sound commonly double, superficial, limited in extent, and not heard along the course of the great blood vessels. Where the disease proceeds on to effusion, as this increases, the friction sound may be gradually lost, at the same time that the area of the heart's dulness as discovered by percussion is markedly increased. Pericarditis is not an uncommon disease, and in itself is commonly attended with little danger; when however the inflammation affects the muscular substance of the heart, the affection becomes one of the gravest character. It commonly requires little treatment; the local abstraction of blood from the cardiac region, and the enforcement of rest with proper regimen, are all that will be found necessary; when effusion has taken place, diuretics may be resorted to; the employment of mercurials is advocated by many practitioners. Occasionally pericarditis is of tubercular origin. Tubercles deposited beneath the pericardium give rise to inflammation, and the plastic matter exuded becomes a nidus for a new forma tion of tubercle. Such pericarditis is essentially chronic, and like tubercular peritonitis it may exist where there is no corresponding development of tubercle in the lung. The disease may be suspected when in a tuberculous constitution pericarditis arises without the coexistence of Bright's disease or rheumatism, or pleuropneumonia, or without the reception of an external injury. In its treatment the patient's strength should be early supported, and while counter-irritation may be employed, cod liver oil, iodine, and the preparations of iron may be administered with some prospect of benefit.-Endocarditis. The lining membrane

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