DENNIE, JOSEPH, an American author and journalist, born in Boston, Mass., Aug. 30, 1768, died in Philadelphia, Penn., Jan. 7, 1812. After a brief experience of mercantile life, he entered Harvard college, where, notwithstanding his vivacious temperament on several occasions brought him into collision with the authorities, he was graduated in 1790. In the same year he commenced the study of law in Charlestown, N. H., and was subsequently admitted to the bar, at which, however, his practice was very inconsiderable. During several months in 1793 he read the Protestant Episcopal church service on Sundays to some members of that denomination in Claremont, and showed such excellent powers of elocution that he was solicited to enter holy orders, with the promise of a settlement in Portsmouth. In 1795, having previously acquired some reputation by literary contributions to various newspapers, under the title of the "Farrago," which had been very generally copied, he became connected with a small weekly journal published in Boston, called the "Tablet." This publication survived its establishment but 3 months, and in the summer of 1795 Dennie removed to Walpole, N. H., and accepted a permanent engagement on the "Farmer's Weekly Museum," a newspaper which enjoyed an extensive popularity toward the close of the last century. His most notable contributions to this were a series of essays, entitled the "Lay Preacher," in which, to use his own language, he sought to "unite the familiarity of Franklin with the simplicity of Sterne." The articles were discursive and lively, were widely copied by the newspapers of the Union, and procured for their author an established position among the few literary men whom the country then possessed. Shortly afterward Dennie assumed the editorship of the "Museum," and by collecting around him a number of able contributors so increased its reputation and circulation, that in the latter part of 1797 the publisher announced with some exultation that the journal was read by upward of 2,000 persons, and had its patrons in Europe and on the banks of the Ohio. In 1798 the bankruptcy of the publisher irretrievably ruined the prospects of the "Farmer's Museum," and Dennie was soon after induced by his friends to become a candidate for congress from New Hampshire. Having been defeated, he left Walpole in 1799 for Philadelphia, to fill the position of confidential secretary to the department of state, over which Timothy Pickering then presided. He remained in office but a few months, and in the latter part of 1800, in connection with Asbury Dickins, commenced the publication in Philadelphia of the "Portfolio," in which he adopted the editorial cognomen of "Oliver Oldschool." At the outset a quarto weekly, it subsequently became a monthly publication. Apart from the contributions of the editor, it was the vehicle of frequent communications from John Quincy Adams, whose letters from Silesia were originally published in it Horace Binney, Judge Hopkin

son, Robert Walsh, Charles Brockden Brown, and other literary men of the time, and maintained for many years a considerable reputation. In 1803 Dennie was indicted for a libel against the federal government, published in his journal, but was acquitted. He continued to be connected with the "Portfolio" until his death, and was highly esteemed for his social qualities as well as for his literary abilities. DENNIS, a post village and township of Barnstable co., Mass., on the peninsula of Cape Cod. The township extends entirely across the peninsula, here 8 m. wide, and is separated from Yarmouth by Bass river. It contains 6 churches, a bank, and some ship yards. Most of the inhabitants are engaged in commerce and the fisheries. About 250 vessels, with an aggregate burden of 35,000 tons, are employed in the coast trade; 10 or 12 ships are engaged in the freighting business, and in 1853 there were 48 vessels (aggregate tonnage 3,160) in the mackerel fisheries. The first settlement was made at Dennis village, in the northwestern part of the township. Pop. in 1855, 3,497. Value of property in 1854 estimated at over $1,000,000.

DENNIS, JOHN, an English critic, born in London in 1657, died Jan. 6, 1733. He was the son of a tradesman, but received a liberal education, and took the degree of A.M. at Cambridge in 1683. Afterward he travelled on the continent, and returned with a strong dislike to the forms of government existing there. He became a whig in politics, and mingled much in the society of the politicians of that school, and of the literary men of London. Among his friends were Dryden, Halifax, Wycherley, and Congreve. By his expensive habits he soon dissipated a small fortune which had been left him by an uncle, and the duke of Marlborough, hearing of his difficulties, obtained for him an appointment in the customs worth £120 a year; but he was compelled, after a while, to sell this to satisfy pressing demands, only reserving from the sale, at the suggestion of Lord Halifax, a small pension for himself for a term of years. This term he however outlived, and was in consequence reduced to great poverty, and becoming blind, was compelled in the latter part of his life to depend upon the charities of literary friends, many of whom he had grossly calumniated. As a dramatist he hardly deserves mention, though some of his plays obtained a transient popularity, especially the one entitled "Liberty Asserted,' in which the French, with whom the English were then at war, were roughly handled. Of his essays the best are the "Grounds of Criticism," and those on Addison's "Cato," and Pope's "Rape of the Lock," though the 2 latter are characterized by the bitterness with which he usually spoke of his contemporaries. Addison had been one of his friends, but he took offence at something which appeared in the 2d and 3d numbers of the "Spectator," and which he supposed to refer to himself, and, in revenge, wrote the essay on "Cato." He was a man of a very peevish and suspicious disposition, and was al

most always engaged in controversy. He attacked Pope, Addison, and Steele; and Pope in return satirized him in several works, especially in the "Dunciad." He had also a most exaggerated idea of his own importance. While the negotiations were in progress previous to the peace of Utrecht, he was in great fear that the French king would refuse to make peace except on condition that the author of "Liberty Asserted" should be delivered over to him. One day, being at the house of a friend on the Sussex coast, and perceiving a vessel in the distance, he was seized with the idea that it was coming to carry him away to France, and that he had been inveigled thither for that purpose. Accordingly he immediately set out for London, congratulating himself on his escape. He had invented a new way of imitating thunder for his play of "Appius and Virginia," which was brought out and failed in 1708; shortly afterward, during the performance of" Macbeth," hearing the thunder produced by his apparatus, he rose in the pit, and exclaimed: "S'death! how these rascals use me; they will not let my play run, yet they steal my thunder." DENOMINATOR, in algebra and arithmetic, the divisor used in producing a fraction. The denominator of a decimal fraction is not written; it is equal to 1, with as many ciphers annexed as there are places in the fraction. The name denominator is derived from its arithmetical use, since it gives the denomination or name to the fraction, 3ds, 5ths, 7ths, &c., while the numerator gives the number of parts taken. DENON, DOMINIQUE VIVANT, baron, a French archæologist, born at Châlons-sur-Saone, Jan. 4, 1747, died in Paris, April 27, 1825. He accompanied Bonaparte to Africa as a member of the Egyptian commission. His Voyage dans la basse et la haute Égypte, which excited much interest on its publication in 1802, was a forerunner of the magnificent work afterward published by the Egyptian commission.

DENSITY, a term somewhat indefinite in meaning, being sometimes used in its true sense, and referring to the number of particles of matter comprised in a given space; sometimes in a secondary sense, as synonymous with specific gravity. In the first sense it is opposed to rarity, and the density of one substance cannot properly be compared with that of another, there being no mode of measuring the absolute size of particles of matter, or their absolute weight. All bodies are believed to be to some extent compressible, and gases are compressible in exact proportion to the force used in compressing them; at least, this is the result obtained by experiment; but it may not be the exact law, and probably does not hold true when the gas is nearly compressed into a liquid, or when the pressure is almost nothing.

DENT, a S. central co. of Mo., recently formed out of the N. part of Shannon co., and named in honor of Frederic Dent, an early settler in Missouri. The soil is fertile, and the surface is much diversified. Pop. in 1856, 3,207, of whom 118 were slaves.

DENT, JOHN H., a captain in the U. S. navy, a native of Maryland, died in July, 1823. He commenced his career as midshipman in March, 1798, under the command of Com. Thomas Truxton, in the frigate Constellation of 36 guns, and was attached to that ship when she captured the French frigate Insurgente, on Feb. 1, 1799. Soon after the engagement he was promoted, and served in the same ship as 4th lieutenant when she captured the French frigate La Vengeance, on Feb. 1, 1800. He served in command of the schooners Nautilus and Scourge, in the squadron of Com. Edward Preble, during the war with Tripoli, and participated in the several attacks upon that city and harbor in the months of July, August, and September, 1804. He was promoted to the rank of master commandant in Sept. 1804, and to that of captain in Dec. 1811.

DENTATUS, MAROUS CURIUS, a Roman consul, who flourished in the 1st half of the 3d century B. C. He was of Sabine origin, and the first of his family that ever filled any high public office. In 290 B. C. he subjected the Samnites; in 275 he vanquished Pyrrhus in two great battles; in 274 he subdued the Samnites, Lucanians, and Bruttians. On the conclusion of his 3d consulship he retired to a small farm in the country of the Sabines, and cultivated it with his own hands. While thus engaged the Samnites sent an embassay to him with costly presents. They found him sitting at the hearth cooking vegetables for his dinner. He rejected their gifts, telling them that he would rather rule over those who possessed wealth than possess it himself. In 272 B. C. he was called to fill the office of censor, in which capacity he constructed an aqueduct which conveyed water from the Anio into the city, and by a canal he carried off the water of the lake Velinus to the Nar, and thus gave to the Reateans a large tract of excellent land. He is said to have been born with teeth; hence his surname of Dentatus.

DENTISTRY, DENTAL SURGERY (Lat. dens, tooth), the surgical treatment of the teeth, including, beside their extraction, the remedying of their serious defects, and the mechanical operation of making and fitting artificial teeth to supply the places of those lost. Although it is only within less than a century that this art has taken the rank of a distinct profession, attention was directed from the earliest periods to the means of preserving and improving the beauty of the teeth. The ancient Hebrew writers evidently appreciated their importance in giving expression to the countenance, as when Jacob blessing Judah says: "His teeth shall be white with milk” (Gen. xlix. 12); and Solomon compares a fine set of teeth to a flock of sheep even shorn (Song of Solomon, iv. 2). In the time of Herodotus the art of dentistry appears to have been practised in Egypt as a distinct branch of surgery, as was also the treatment of the diseases of the eye and of the ear. Little, however, is known of the attainments of these early practitioners. In the ancient tombs

of this people artificial teeth of ivory or wood were found by Belzoni and others, some of which were fastened upon gold plates. It is also stated that teeth of the mummies have been found filled with gold. Thus it would seem that the ancient Egyptians understood processes of the art which are commonly regarded only as inventions of the refined nations of modern times. Artificial teeth are alluded to by several of the Greek and Latin poets, as Ovid, Martial, Horace, &c. The works of Galen, written in the 2d century, contain the earliest treatises upon this subject, and they continued to be the best until the works of Fallopius, Eustachius, and Ambrose Paré appeared in the 14th, 15th, and 16th centuries. During the 18th century the attention of medical men in France and England was directed to the subject, and a number of elaborate works were published devoted exclusively to the art. These, and prominently among them the treatise of John Hunter (1771-'78), laid the foundation of the English school of dentistry. The subject, however, was treated anatomically and philosophically rather than practically; and the same may be said of the writings of the eminent French surgeon of this period, Bichat. Neither of these was a practical dentist, and the subsequent publications of Dr. Blake in 1798, and of Fox in 1803 and 1806, as of others at later dates, served rather to elucidate the physiology of the teeth and the nature of the diseases to which they are subject than the method of treating them. From advertisements in the newspapers of 1703 the practice of the art, making teeth and cleaning them, appears to have been in the hands of silversmiths or jewellers. In 1826 the eminently practical work, "Principles of Dental Surgery," of Leonard Koecker, M.D., who had practised dentistry from 1807 to 1822 in Baltimore and Philadelphia, appeared in London, and fully established the claims of the art to take rank as a distinct branch of science. From that time new treatises by able writers and practitioners have continued frequently to appear. The progress of the French school was very rapid in the early part of the present century. Prof. Baume's treatise on first dentition and the diseases that accompany it appeared in the year 1800; and 2 years afterward, a work on the theory and practice of the art, by Laforgue. The former has been translated into English, and incorporated into the "American Journal of Dental Science." The works of Duval, interesting for their historical research as well as their practical instruction, have been much read. Leroy's work on diseases of the gums (1806) has been translated and published in the "American Journal." A number of works were published by Delabarre between the years 1815 and 1826 on different subjects relating to the teeth and their treatment. Among them is a treatise on "Mechanical Dentistry," published in 1820, and illustrated with 42 plates. It was during this period, when publications upon dentistry were frequently appearing in

France, that the manufacture of artificial teeth of porcelain was introduced; and in 1821 a work upon this subject was published by Audibran of nearly 200 pages, entitled Essai historique et pratique sur les dents artificielles incorrup tibles. By this it appears that Fauchard in 1728 proposed their manufacture; and that in 1776 Duchateau, a chemist of St. Germain-enLaye, attempted to produce them, and finally succeeded with the aid of Dubois, a dentist of note in Paris. The latter imitated the colors of the natural teeth and gums by the use of mineral oxides, and obtained royal letters patent from Louis XVI. for the invention. The progress of this branch of the art will be particularly noticed in the latter part of this article.-The practice of dentistry was introduced into the United States by Le Mair, of the French forces which joined our army during the revolutionary war. An Englishman named Whitlock also commenced the practice soon after the arrival of Le Mair. About the year 1788 Mr. John Greenwood established himself in New York, the first American of this profession. In 1790, and again in 1795, he carved in ivory an entire set of teeth for Gen. Washington. They were secured by spiral springs, and the neatness and ingenuity of the work was considered equal to any executed at that period abroad. Other dentists soon appeared in New York, Philadelphia, and Baltimore. Their work included the extracting of teeth, filing and cleaning them, and replacing the natural teeth when lost with artificial ones, commonly made of ivory. Dr. Hudson, formerly of Dublin, who had settled in Philadelphia, first directed his attention particularly to the cure of the diseases of the teeth, and to arresting the progress of dental caries. In 1820 the number of practitioners in the United States was probably little more than 100. Ten years afterward, as estimated by Dr. C. A. Harris, in his work on the "Principles and Practice of Dental Surgery," there were about 300, of whom probably not more than were well instructed. But the increase in their numbers was afterward very raipd. In 1842 they were believed to number about 1,400, and in 1858 about 4,000. An important event in the history of dental surgery in this country was the establishment of the "American Journal and Library of Dental Science" in Baltimore, in 1839. The society of dental surgeons was soon after formed, and at its second annual meeting the "Journal" was made the property and organ of the association. Maryland, which appears to have taken the lead of the other states in this department of science, founded by its legislature, a few months previous to the organization of the society above named, a college of dental surgery, with 4 professorships, designed for instruction in the principles and mechanical practice of the art. Two years afterward another society of dentists, like that of Baltimore, was organized at Richmond, Va., and in Aug. 1844, a third was formed at Cincinnati, Ohio, styled the "Mississippi Valley Association of Dental Surgeons." A college of

dentistry has also been established in Philadelphia and another in Cincinnati, and state and local dental societies in various parts of the country. In Aug. 1855, the national convention of dentists was organized, through the active exertions of Dr. Elisha Townsend of Philadelphia, and its first annual meeting was held in that city. Dr. John B. Rich of New York was its first president. Beside the reports of these societies, which have disseminated a knowledge of the discoveries and improvements made in the science, many very valuable works of a practical nature have been published by American authors, among which may be noticed a treatise by J. Gardette of Philadelphia, originally of Paris. This was published in 1821. In 1822 appeared in New York and London an essay on the "Disorders and Treatment of the Teeth," by Dr. E. Parmly; also, the same year, 2 volumes by Dr. L. S. Parmly, and a work called the "Family Dentist," by J. F. Flagg, M.D., of Boston. In 1829 a comprehensive treatise, and probably the most valuable ever published to that time, appeared, in one volume of over 500 pages, written by S. S. Fitch, M.D.; in 1835 a second and improved edition was published. A poetical essay, entitled Dentologia, by Dr. Solyman Brown, with notes by Dr. E. Parmly, is a curious and ingenious production, which appeared in 1833. The same author also published other works and many valuable papers on dentistry. The "Guide to Sound Teeth," by S. Spooner, M.D., is a valuable work, printed in 1836. The "Principles and Practice of Dental Surgery," by Prof. C. A. Harris, of the Baltimore college, is a standard text book of 600 pages 8vo.; the second edition was published in 1845. Dr. Harris also published a large 8vo. dictionary of dental surgery. In 1854 a comprehensive 8vo. volume was published by A. Snowden Piggot, M.D., entitled "Chemistry and Metallurgy as applied to the Study and Practice of Dental Surgery." A number of periodicals are supported by the profession, as the "Dental Register of the West," a quarterly, published in Cincinnati; "Dental Review," St. Louis, quarterly; "Dental News Letter," Philadelphia; the "Obturator," New Orleans, &c.-From this sketch of the history and progress of the science, it is apparent how highly its cultivation is appreciated among civilized nations. Ruder people also show a regard for the teeth, which is oftener displayed, however, in attempts to ornament them by coloring and giving to them grotesque shapes, than by devising means to preserve them. This last, indeed, is little required with people living the inartificial life of savages, and subsisting upon the simple food they use. Their teeth partake of the perfect development of their physical constitution, and are generally sound, healthy, and beautifully white. The natives of Hindostan, and the high caste Brahmins especially, are said to devote particular care to the preservation of these organs. With them it is a religious duty, inculcated in their most ancient books, to pay scrupulous regard to their cleanliness. Every

morning they spend an hour rubbing them with a twig, while performing at the same time their devotional exercises. The result is that they have the finest teeth of any people. The progress of dentistry as a science has been necessarily consequent upon that of anatomy. As the physiology of the system was better understood, the relations of the various organs to each other, and their mutual dependence, were more clearly perceived. Dentistry ceased to be a merely mechanical art, when the treatment of the teeth demanded a comprehension of these relations, and when he who practised it paused before operating, to consider whether the pain he hoped to remove with instruments might not better be alleviated by proper medical treatment, by the application of leeches to the gums, or, when it was of the nature of neuralgia, by the surgical operation of dividing the affected nerve. So intimately connected is the welfare of the teeth with that of the general system, that some knowledge of medicine, and of the diseases whose effects may reach these organs, is indispensable to the scientific dentist. His knowledge of anatomy is not confined to the bony structure of the tooth, to the soft pulp which fills its internal cavity, to the position of the nerves which communicate its complaints to the brain, nor to the manner in which it is held so fast in its socket. His science involves an acquaintance with the anatomical relations of the organs of the mouth with all parts of the system. The mucous membrane that lines it extends to the stomach and other internal organs, as the liver, intestinal canal, and those of respiration, through the larynx, trachea, and bronchi. An unhealthy condition in one part of this membrane is manifested in another. Canker, the cause of which is in the stomach, appears as a disease of the gums or the tongue. When this member is furred or coated with an unhealthy secretion, it is an indication of disease in the intestines or other internal organs. The teeth may be injuriously affected by this unhealthy secretion, the remedy for which is to be applied to other organs. The nerves, spread like a network throughout the whole system, are affected frequently in the teeth by the diseases of distant members; and an operator unskilled in their affections often sacrifices sound teeth without_benefiting the sufferer by their removal. Dr. Harris mentions an instance of a gentleman, who, afflicted by such an affection of the nerves, had all the teeth on the right side of both jaws thus uselessly removed. Mr. Fox, the anatomist and physiologist, as well as dentist, being applied to in a similar case, suspected the real nature of the disease, and taking the patient to Sir Astley Cooper, a radical cure was effected by the operation of dividing the affected nerve. The effects of this connection through the nerves are reciprocal, and other members suffer in consequence of diseased teeth. Baglivi noticed this in his Canones Medicina, published in 1710: "Persons whose teeth are in an unclean and

viscid state, though daily washed, have uniformly a weak stomach, bad digestion, an of fensive breath, headache after meals, generally bad health, and low spirits." Physicians, when consulted in chronic and nervous affections, often now examine the teeth, and refer the patient to the dentist. Many cases of that terrible disease, neuralgia faciei, which have resisted all other treatment, have been cured by the removal of diseased teeth. The nerves belonging to the eye, ear, nose, mouth, and which pass over the cheek and are distributed in many branches through the teeth, are ramifications of the great nerve of sensation, the 5th of the anatomist. Whatever part of this chain be irritated, the pain may be experienced in any other part. Thus, stumps of teeth, lying apparently harmless, may be the cause of terrible neuralgic pains in the head, as well as, for the other reason above given, of a number of other diseases apparently originating from the stomach, or often attributed in common language to impure condition of the blood.-The means of preventing the diseases to which the teeth are subject, is a branch of dental science quite as important as that relating to the arrest and cure of these diseases. These means consist, first, in giving what assistance nature requires to bring the teeth of second dentition into a regular arrangement; and secondly, in the care of the individual himself in preserving the teeth uniformly clean. As the temporary or first set of teeth drop out, which as a general rule they should be allowed to do, by their roots being absorbed, the second set already formed succeed and take their places. Of the temporary teeth there are but 20, and these are of small size. The teeth of the second dentition are 32 in number, with one or two exceptions are of larger size than their predecessors, and consequently occupy a greater space. Yet these, appearing one by one, take their places, and should occupy in the harmonious process of the growth of all the parts the same room apparently that was filled by the 20 deciduous teeth. This is accomplished by the elongation forward of the jaw, and the arch gradually assuming the form of a semi-ellipse in place of that of a semi-circle. But if any of the first teeth have been indiscreetly removed before their time, or as indiscreetly allowed to remain so as to interfere with the growth of the permanent teeth, an inequality of resistance is offered to the progress of some of the second set, which is apt to cause an irregularity in their arrangement. The same effect is often produced without any apparent cause other than that the increase of the teeth and that of the jaw do not proceed pari passu. A tendency to this is often noticed to be hereditary. Teeth irregularly arranged, interfering with each other, or as they sometimes do with the lips, or pointing inward so as to be removed from the healthy action of mastication, or twisted in their sockets, are not only disfiguring, but are particularly liable to disease and decay. From

their first appearance to the age of 16 of the individual, they may be treated by various mechanical applications attached to the other teeth and bearing suitably upon those to be brought into place, so that without violence the work of nature is gently assisted, and a perfect set is gradually formed. So essential is this to the future welfare of the teeth, that by due attention of this kind, in the opinion of an eminent dentist, "there would not be one decayed tooth where now there are a dozen." ." (Harris, p. 134, 2d ed.) Cleanliness is the second requisite for sound teeth. The principal cause of their decay is generally admitted to be the presence of decomposing particles of food lodged between them. All dentists strongly urge the importance of children early acquiring the habit of brushing the teeth twice daily. Dr. L. S. Parmly goes so far as to say: "Where the teeth are kept literally clean, no disease will ever be perceptible. Their structure will equally stand the summer's heat and winter's cold, the changes of climate, the variation of diet, and even the diseases to which the other parts of the body may be subject from constitutional causes." By neglect of this duty the teeth are likely to be soon affected with caries. This disease may go on insidiously and unsuspected, involving not merely the risk of loss of these organs, but, unless exposed by the intense pain, which by a wise and beneficial provision it commonly involves, affecting the general health of the individual, and inducing maladies of the most alarming character. Many cases of disease thus engendered it is too often the province of the dentist to treat, and the life of the patient is not always saved even by the sacrifice of all the teeth. Čaries of the teeth is also induced by vitiated secretions of the mouth arising from severe constitutional disorders, or the continued administration of different kinds of medicine; or it is sometimes due to a predisposition inherited from one or both parents. Its treatment is to remove the affected part, when this is superficial, by the use of the file. The surface of the bone from which the enamel is removed must be left smooth and polished, and if proper care be afterward taken in keeping it clean, the disease may not return. If the decay has extended into the bony substance of the tooth, the filing is then only preparatory to the complete removal of the diseased portion by excavating with suitable instruments, and filling the cavity with some proper material. Much attention was formerly given to shaping the cavity, in order that by its contracted aperture the filling should be held in as by dovetailing; but by the use of gold foil and sponge gold specially prepared for this purpose, it is now found practicable to apply the metal in successive portions, and build up a solid block of any shape by incorporating each portion with that which preceded it. This is done by a sort of stippling with suitable instruments, and the gold may be thus rendered so compact, it is affirmed, that its specific gravity shall