shaped as already described, the gold plug should be secured and consolidated piece by piece, until there is built up a mass filling every part of the vacant space with a uniform consistency of metal which, when finished, ought to present the feeling of being as hard as a piece of solid gold. The other fillings are more easily dealt with. The same careful preparatory steps are requisite in all fillings, but the insertion of the plug in amalgam and other stoppings being performed while the material is in a plastic condition, the process is rendered much more simple. The cavity should be completely filled, but not over-filled, and the amalgams ought to be used with as little mercury as is at all possible. A number of instruments are necessary for effecting all these various manipulations, but to describe them here would be as unintelligible as it appears unnecessary. Excavators, enamel cutters, burr head drills, points, pluggers, burnishers, &c., are only some of those required; while their modes of use are either by the hand or by mechanical-apparatus, such as what are termed burringengines, &c. Stopping may be regarded as one of the most valuable operations in modern dentistry; and although it is no guarantee that the tooth stopped is ever after safe from the renewed attack of caries any more than its unstopped neighbours are from its original attack, yet it is surprising how few well-filled teeth are lost by caries recommencing in the stopped cavity.

Besides those already mentioned, the teeth and jaws are subject to a number of disorders and lesions which it would be out of place here to do more than enumerate. Fracture and dislocation of the teeth, ulceration and absorption of the gum, necrosis and exfoliation of the jaw, alteration in the secretions of the mouth, the deposit of tartar or salivary calculus on the teeth or in the salivary, ducts, the effect of various medicines and poisonous agents on the teeth, jaws, and mouth generally, these and the like matters are all of much interest, and more or less connected with dentistry proper. But for information in regard to them the reader must be referred to the various excellent publications treating of them, which have appeared in considerable numbers since dental surgery has occupied more notice and taken a place as one of the recognized specialities of medicine. Mechanical dentistry, properly so called, consists in the construction of artificial substitutes to supply the place of lost teeth. Stopping and such like operations might also be classed with mechanical dentistry as contrasted with purely surgical treatment; as yet, however, these matters are not quite decided; and the day when the dental surgeon and the mechanical dentist-like the ophthalmic surgeon and the optician-should each occupy a separate sphere has not arrived. All that can here be given is a mere outline of the principles involved in mechanical dentistry. The subject is one comprehending a knowledge of many departments of mechanical seience; and to do more than indicate the nature of the various modes of construction, and the processes carried on in the manufacture of artificial teeth, would be useless and inexpedient.

The removal of roots and stumps as a preparatory step in the fitting of artificial teeth is a matter to be decided by the circumstances of the case. The length of time which can be afforded for cicatrization and absorption of the alveolar walls and gum ; the presence of adjoining teeth to be left standing, especially front teeth; the fitness of the patient for the operation of extraction,-these and other circumstances must determine what amount of surgical preparation is to precede the supplying of false teeth. As a general rule, the clearer the gums are of stumps and decayed teeth the better; but at the same time certain advantages, transitory as they may be, are in some instances to be derived from their retention.

The jaw, gum, and teeth being then considered as in a suitable condition, the first step in the process is to obtain a plaster cast of the parts,-"the model," as it is termed. This is done by pressing softened beeswax or some similarly plastic composition against them until they are imbedded and leave an impression in it, giving an exact mould of the gums, remaining teeth, and all other parts on its removal. Plaster of Paris is now run into the mould so obtained, and when this is set and hardened a perfect facsimile of the structures to be fitted is the result.

Any further proceedings now depend upon the mode and material in which the future artificial set is to be constructed. Every set of artificial teeth consists of representatives of the lost organs, modelled in a species of porcelain, and mounted upon a base adjusted to the gum and remaining natural teeth. This base is manufactured in a variety of materials, the principal of which are-(1) metal plate, of gold, platinum, silver, or different alloys; (2) vulcanized caoutchouc, or vulcanite, as it is called; and (3) celluloid base, a composition of collodion and camphor, which has not been long enough tested as yet to rank with the other substances; while (4) the teeth may be mounted merely with as much extraneous material as will support a pin or pivot by which they may be attached as new crowns to a root in which such pivot is firmly inserted. When it is intended that the base shall be of gold or other plate, a metal die and counter have to be made from the plaster model, between which dies the plate is embossed, and the requisite form obtained. The die and counter die are generally made the one in zinc or gun metal, the other in lead or tin; and-unlike the dies from which jewellery patterns, &c., are embossed, and which may serve for thousands of times-the dental dies, having served to emboss the plate for one patient, are of no further use for any other case. The plate being thus far advanced next requires to be adjusted to the mode in which the patient closes the opposing jaw or teeth against it in shutting the mouth-in other words, the "bite" has to be taken, and the artificial teeth, which are to be mounted on the plate, arranged accordingly. Any fastenings supporting or steadying the set have also to be adjusted; and after this, if everything has gone well, the false set should be ready for placing in its destined locality and for use by the wearer. Should it be proposed to make the base of vulcanite, celluloid base, or a similar material, a different mode of procedure must be adopted. These materials necessitate a greater bulk of substance occupying the mouth than is the case where metal plate is employed. This, however, is in some cases an advantage-since, for instance, where the gum has been greatly diminished in size through absorption, it requires some bulk of material to restore the parts to their normal size, and to give the former natural expression to the features. In preparing a vulcanite base no metal die is necessary. The base is built up in wax directly on the plaster model, and the porcelain teeth adjusted in their places, the bite and attachments being carefully attended to, as described in speaking of plate cases. The set thus made up, and presenting the exact counterpart of what the finished work is intended to be, is now, after testing it and finding it correct and perfect in the mouth, imbedded in Paris plaster as follows. A small box, or "flask," as it is denominated, of iron or other metal, like one saucer inverted on the top of another, is opened and the model with the wax-built set on it is placed in the lower saucer, which is then filled up with plaster to the level of the wax set. This being allowed to harden is soaped or oiled all over its surface, and the lid of the flask, or what corresponds to the upper saucer, is now placed upon the under portion of the flask. An opening in this covering portion enables plaster to be next poured into it till the inclosed

wax-mounted set is shut up like a fossil in the heart of its stony covering. On the two halves of the flask being separated, the set of course remains firmly secured in the lower portion. Boiling water is ow poured over it, and the wax thus melted out, leaving the porcelain teeth undisturbed and in situ. A cavity is thus left when the two sides of the flask are again closed, represer ting exactly the form of the wax removed. Raw vulcanite, o whatever other material of the kind is to be used, is now introduced with care into the space thus left by the removal of the wax. The two sides of the flask are next brought together and maintained there by the pressure of a clamp and Screw. The whole is then placed in a vessel termed a vulcanizer, where it is subjected, for the space of from an hour and a quarter to two hours or more, to the action of steam at a temperature ranging up to 320° Fahr., at the end of which time the piece will be found hard and ready for finishing and polishing as may be desirable. In firing and manipulating the celluloid base some modification of this process is required, but as yet the substance is comparatively little used, and would scarcely justify further remark in this place.

What is termed a pivot tooth, again, is an artificial tooth having a metal or sometimes a wooden pin firmly attached to it; and this being inserted into the opened pulp cavity of a healthy fang, the artificial forms a secure and very perfect substitute for the original crown when destroyed by caries, broken off, or otherwise lost.

The use of artificial teeth, especially by those previously vnaccustomed to them, requires considerable practice and no small amount of perseverance. The larger the artificial set, that is, the greater the number of teeth replaced,— the greater the difficulties and the more the discomfort ex perienced. Time, however, works wonders here as in many other instances. It is not an uncommon thing to find a set which never has fitted well, or one which owing to many years of use does not fit well, being felt so comfortable, through mere habit of wearing it, that on a new and perfectly fitting set being made, the old one, with all its faults, is preferred to the other. A few days' wear, however, of the new one generally brings all the shortcomings of the old glaringly out on its being again attempted to be worn. And in the same manner, a week or two's perseverance generally enables any ordinary set to be worn and used with comfort and facility even by patients who are for the first time under the dentist's care. Various modes of fixation are adopted for the retaining of artificial teeth in their proper situation. Atmospheric pressure, or "suction," as it is termed, is the simplest of all, being merely the hold established between the palate and the set in the same way as occurs between a wet leather "sucker" and the stone it lifts. Another method is by what are termed "spiral springs,” a mode only applicable, however, where both an upper and lower set are worn at the same time. And a third style of fixation is where the set is supported upon certain natural teeth among those remaining in the patient's jaw. Each mode has its own advantages, and sometimes one or other method is the only one at all possible to be adopted. This, however, is seldom a difficult matter to decide by any one who has had much experience of either the operating room or the dental workshop.

The art of dentistry is difficult to acquire, and comprehends in itself processes appertaining to several separate branches of manufacture. It is, however, an art which is an extremely useful one, and has done valuable service, since it is not too much to say that in all probability many lives have been saved and a still greater number prolonged through the instrumentality of the aid afforded by the use of artificial teeth.

Literature of the subject and authoritics on Dental Surgery. – Goodsir, Edinburgh Medical Journal, 1838; Heath, On Diseases of the Jaws, 1868; Owen, On the Skeleton and Teeth, 1855 Tome's Dental Surgery, 1873; Taft's Operative Dentistry, 1877; Salter's Dental Pathology, 1874; Smith's Dental Anatomy and Surgery, 1864, and various papers in Edinburgh Medical Journal, Proceedings of Royal Society of Edinburgh, &c., from 1852; Cole's Turner's Human Anatomy, 1877; Richardson's Mechanical Den Dental Mechanics, 1876; Waldeyer, in Stricker's Handbuch, 1870 ; tistry, 1860; Wedl's Pathology of the Teeth, 1860; various papers, by Kolliker, Arnold, Boll, Robin and Magitot, Huxley, &c., in British and Continental journals. (J. S.*)

DENVER, a city of the United States of America, capital of the State of Colorado, and of Arapahoe county, occupies a commanding position on the south bank of the South Platte river, where it is joined by the Cherry creek, 500 miles west of the Missouri,-its elevation above the level of the sea being 5267 feet. The town, which is of recent origin, and mostly built of brick, contains some large public buildings connected with the State administration, as well as a large public school, a State library, and churches belonging to the different denominations. It forms the centre of an important railway system, and has several factories engaged in smelting, iron founding, and wood work, besides a mint for assaying gold and silver ore, breweries, wool mills, &c. The population, which numbered 4759 in 1870, and was estimated at 15,000 in 1873, is rapidly increasing.

races.

DEODAND (Deo dandum), in English law, was а personal chattel (any animal or thing) which, on account of its having caused the death of a human being, was forfeited to the king for pious uses. Blackstone, while tracing in the custom an expiatory design, alludes to analogous Jewish and Greek laws, which required that that what occasions a man's death should be destroyed. In such usages the notion of the punishment of an animal or thing, or of its being morally affected from having caused the death of a man, seems to be implied. The forfeiture of the offending instrument in no way depends on the guilt of the owner. The imputation of guilt to inanimate objects or to the lower animals, repugnant as it is to our habits of thought, is not inconsistent with what we know of the ideas of uncivilized In English law, deodands came to be regarded as mere forfeitures to the king, and the rules on which they depended were not easily explained by any key in the possession of the old commentators. The law distinguished, for instance, between a thing in motion and a thing standing still. If a horse or other animal in motion killed a person, whether infant or adult, or if a cart run over him, it was forfeited as a deodand. On the other hand, if death were caused by falling from a cart or a horse at rest, the law made the chattel a deodand if the person killed were an adult, but not if he were a person below the years of discretion. Blackstone accounts for the greater severity against things in motion by saying that in such cases the owner is more usually at fault, an explanation which is doubtful in point of fact, and would certainly not account for other instances of the same tendency. Thus, where a man's death is caused by a thing not in motion, that part only which is the immediate cause is forfeited, as "if a man be climbing up the wheel of a cart, and is killed by falling from it, the wheel alone is a deodand," whereas, if the cart were in motion, not only the wheel but all that moves along with it (as the cart and the loading) are forfeited. A similar distinction is to be found in Britton. Where a man is killed by a vessel at rest the cargo is not deodand; where the vessel is under sail, hull and cargo are both deodand. For the distinction between the death of a child and the death of an adult Blackstone accounts by suggesting that the child "was presumed incapable of 1 Compare also the rule of the Twelve Tables, by which an animal which had inflicted mischief might be surrendered in lieu of compensation.

actual sin, and therefore needed no deodand to purchase | propitiatory masses; but every adult who died in actual sin stood in need of such atonement, according to the humane superstition of the founders of the English law." Sir Matthew Hale's explanation was that the child could not take care of himself, whereon Blackstone asks why the owner should save his forfeiture on account of the imbecility of the child, which ought to have been an additional reason for caution. The finding of a jury was necessary to constitute a deodand, and the investigation of the value of the instrument by which death was caused occupies an important place among the provisions of our early criminal law. It became a necessary part of an indictment to state the nature and value of the weapon employed-as, that the stroke was given by a certain penknife, of the value of sixpence so that the king might have his deodand. Accidents on the high seas did not cause forfeiture, being beyond the domain of the common law; but it would appear that in the case of ships in fresh water, the law as quoted above from Britton held good. The king might grant his right to deodands to another.

In later times these forfeitures, so unintelligible in their purpose, so capricious and unjust in operation, became extremely unpopular; and juries, with the connivance of judges, found deodands of trifling value, so as to defeat the inequitable claim. But deodands were not abolished till the 9 and 10 Vict. c. 62 was passed, whereby it is enacted that "there shall be no forfeiture of any chattel for or in respect of the same having caused the death of a man; and no coroner's jury sworn to inquire, upon the sight of any dead body, how the deceased came by his death, shall find any forfeiture of any chattel which may have moved to or caused the death of the deceased, or any deodand whatsoever; and it shall not be necessary in any indictment or inquisition for homicide to allege the value of the instrument which caused the death of the deceased, or to allege that the same was of no value." The date of this Act (1846) may suggest the great inconvenience which the law, if it had remained in operation, would have caused to railway and other enterprise in which loss of life is a frequent occurrence.

DEPRÈS, JOSQUIN (1440-1521), also called Desprez, and, by a Latinized form of his name, Jodocus Pratensis or a Prato, a celebrated musical composer, was born about 1440 at Vermand, near St Quentin, in French Flanders. He was a pupil of Ockenheim, the great contrapuntist, and himself one of the most learned musicians of his time. In spite of his great fame, the accounts of his life are vague and scanty, and even the place of his birth has only lately been established beyond dispute-Belgians, Germans, Italians, and Frenchmen claiming him as their countryman. M. Fétis, the well-known historian of music, has contributed greatly towards elucidating the doubtful points, and to that author's Biographie Universelle the reader is referred for more detailed information. In his early youth Josquin seems to have been a member of the choir of the collegiate church at St Quentin; when his voice changed he went (about 1455) to Ockenheim to take lessons in counterpoint; afterwards he again lived at his birth-place for some years, till Pope Sixtus IV. invited him to Rome to teach his art to the musicians of Italy, where musical knowledge at that time was at a low ebb. In Rome Deprès lived till the death of his protector (1484), and it was there that many of his works were written. His reputation grew rapidly, and he was considered by his contemporaries to be the greatest master of his age. Luther, himself an excellent musical amateur, is credited with the saying that "other musicians de with notes what they can, Josquin what he likes." The composer's journey to Rome is in itself a most important part in the history of musical progress; for it marks in a

manner the transference of the art from its Gallo-Belgian birth-place to Italy, which for the next two centuries remained the centre of the musical world. To the school of the Netherlands, of which Deprès and his pupils Arcadelt, Mouton, and others are the chief representatives, modern music owes its rise. But far more important than this school itself was its outgrowth and successor, the so-called Roman school, immortalized by the name of Palestrina. After leaving Rome Deprès went for a time to Ferrara, where the art-loving duke Hercules I. offered him a home; but before long he accepted an invitation of King Louis XII. of France to become the chief singer of the royal chapel. According to another account, he was for a time at least in the service of the emperor Maximilian I. The date of his death has by some writers been placed as early as 1501. But this is sufficiently disproved by the fact of one of his finest compositions, A Dirge (Déploration) for Five Voices, being written to commemorate the death of his master Ockenheim, which took place after 1512. The real date of Josquin's decease has since been settled as the 27th August 1521. He was at that time a canon of the cathedral of Condé. The most complete list of Deprès's compositions-consisting of masses, motets, psalms, and other pieces of sacred music-will be found in Fétis. The largest collection of his MS. works, containing no less than 20 masses, is in the possession of the Papal chapel in Rome. The well-known works by Drs Burney and Hawkins give specimens of his music.

DEPTFORD, a town of England situated at the junction of the Ravensbourne with the Thames, 3 miles east of London Bridge. It forms the western portion of the parliamentary borough of Greenwich, occupying an area of about 1650 acres, situated mostly in the county of Kent, and partly in Surrey. It comprises two parishes-that of St Nicholas, including Lower Deptford on the Thames, and St Paul's, or the landward part of the town, which extends into Surrey and includes Hatcham Manor. Lower Deptford consists of irregular narrow streets, and the houses are mostly of a mean description. It contains the site of the old dockyard, and the royal victualling yard is also situated there. The former was discontinued as a dockyard in 1869; it was filled up and converted into a foreign cattle market by the corporation of London, but this was given up in 1873. The victualling yard immediately to the west of it is the most important establishment of its kind in the kingdom, supplying the navy with provisions, medicines, furniture, &c., which are manufactured or stored in the large warehouses that constitute the establishment. As many as 500 hands are employed in the warehouses and at the lading wharf. The only other industrial employment of importance in the place is to be found in the engineering works, which are carried on near the river. Of public buildings the most noteworthy are St Nicholas Church, with a square embattled tower, built on the site of an older structure at the beginning of the last century, and St Paul's, of classic design, erected in 1730. There is also the hospital for master mariners, maintained by the corporation of the Trinity House, which was originated here. Of the mansion known as Sayes Court, with which Deptford is historically identified, nothing now remains but the garden. The house-taken down in 1729was the residence of the duke of Sussex in Queen Eliza beth's time; it was occupied in the following century by John Evelyn, the author of Sylva, and by Peter the Great during his residence in England in 1698. The popula tion of Deptford in 1871 amounted to 60,188 persons, seven-eighths living in the landward parish of St Paul's.

DE QUINCEY, THOMAS (1785-1859), an eminent English author, was born at Greenhay, near Manchester,

of readers and admirers, as they are safe to do in those of a third and fourth. The risk of their not reaching on through succeeding time arises from their diffuseness-their power is weakened by their volume.

De Quincey has fully defined his own position and claim to distinction in the preface to his collected works. These he divides into three classes :-"first, that class which proposes primarily to amuse the reader," such as the Narratives, Autobiographic Sketches, &c.; "second, papers which address themselves purely to the understanding as an insulated faculty, or do so primarily," such as the essays on Essenism, the Caesars, Cicero, &c.; and finally, as a third class, "and, in virtue of their aim, as a far higher class of compositior s," he ranks those "modes of impassioned prose ranging under no precedents that I am aware of in any literature," such as the Confessions and Suspiria de Profundis. The high claim here asserted has been so far questioned; and short and isolated examples of eloquent apostrophe, and highly-wrought imaginative description, have been cited from Rousseau and other masters of style; but De Quincey's power of sustaining a fascinating and elevated strain of "impassioned prose" is allowed to be entirely his own. In this his genius most emphatically asserts itself; if it be not admitted that in that dread circle none durst walk but he, it will be without hesitation conceded that there he moves supreme. Nor, in regard to his writings as a whole, will a minor general claim which he makes be disallowed, namely, that he "does not write without a thoughtful consideration of his subject," and also with novelty and freshness of view. Generally," he says, "I claim (not arrogantly, but with firmness) the merit of rectification applied to absolute errors, or to injurious limitations of the truth." Another obvious quality of all his genius is its overflowing fulness of allusion and illustration, recalling his own description of a great philosopher or scholar-"Not one who depends simply on an infinite memory, but also on an infinite and electrical power of combination, bringing together from the four winds, like the angel of the resurrection, what else were dust from dead men's bones into the unity of breathing life." It is useless to complain of his having lavished and diffused his talents and acquirements over so vast a variety of often comparatively trivial and passing topics, instead of concentrating them on one or two great subjects. The world must accept gifts from men of genius as they offer them; circumstance and the hour often rule their form. Those influences, no less than the idiosyncrasy of the man, determined De Quincey to the illumination of such matter for speculation as seemed to lie before him; he was not careful to search out recondite or occult themes, though these he did not neglect,—a student, a scholar, and a recluse, he was yet at the same time a man of the world, keenly interested in the movements of men and in the page of history that unrolled itself before him day by day. To the discussion of things new, as readily as of things old, aided by a capacious, retentive, and ready memory, which dispensed with reference to printed pages, he brought also the exquisite keenness and subtlety of his highly analytic and imaginative intellect, the illustrative stores of his vast and varied erudition, and that large infusion of common sense which preserved him from becoming at any time a mere doctrinaire, or visionary. If he did not throw himself into any of the great popular controversies or agitations of the day, it was not from any want of sympathy with the struggles of humanity or the progress of the race, but rather because his vocation was to apply to such incidents of his own time, as to like incidents of all history, great philosophical principles and tests of truth and power. In politics, in the party sense of that term, he would probably have been classed as a Liberal Conservative

or Conservative Liberal-at one period of his life perhaps the former, and at a later the latter. Originally, as we have seen, his surroundings were somewhat aristocratic, in his middle life his associates, notably Wordsworth, Southey, and Wilson, were all Tories; but he seems never to have held the extreme and narrow views of that circle. Though a flavour of high breeding runs through his writings, he has no vulgar sneers at the vulgar. As he advanced in years his views became more and more decidedly liberal, but he was always as far removed from Radicalism as from Toryism, and may be described as a philosophical politician, capable of classification under no definite party name or colour. Of political economy he had been an early and earnest student, and projected, if he did not so far proceed with, an elaborate and systematic treatise on the science, of which all that appears, however, are his fragmentary Dialogues on the system of Ricardo, which John Ramsay M'Culloch pronounces "unequalled for brevity, pungency, and force." 3ut political and economic problems largely exercised his thoughts, and his historical sketches show that he is constantly alive to their interpenetrating influence. The same may be said of his biographies, notably of his remarkable sketch of Dr Parr. Neither politics nor economics, however, exercised an absorbing influence on his mind,-they were simply provinces in the vast domain of universal speculation through which he ranged "with unconfined wings." How wide and varied was the region he traversed a glance at the titles of the papers which make up his collected-or more properly selected-works (for there was much matter of evanescent interest not reprinted) sufficiently shows. He was equally at home in all provinces, though never exerting his great powers so as to make himself paramount in any. Surprising as his literary achievements are, his capabilities were still greater; and the general survey leaves the impression of regret that, doing so much so well, he did not do more, or did not less better. Some things in his own line he has done perfectly; he has written many pages of magnificently mixed argument, irony, humour, and eloquence, which, for sustained brilliancy, richness, subtle force, and purity of style and effect have simply no parallels; and he is without peer the prince of dreamers. The use of opium no doubt stimulated this remarkable faculty of reproducing in skilfully selected phrase the grotesque and shifting forms of that "cloudland, gorgeous land," which opens to the sleep-closed eye; but the faculty itself was a speciality of his constitution, coloured by the quality of his genius, and enriched by the acquisitions of his intellect.

To the appreciation of De Quincey the reader must bring an imaginative faculty somewhat akin to his own-a certain general culture, and large knowledge of books, and men, and things. Otherwise much of that slight and delicate allusion that gives point and colour and charm to his writings will be missed; and on this account the full enjoyment and comprehension of De Quincey must always remain a luxury of the literary and intellectual. But his skill in narration, his rare pathos, his wide sympathies, the pomp of his dream-descriptions, the exquisite playfulness of his lighter dissertations, and his abounding though delicate and subtle humour, commend him to a larger class. Though far from being a professed humourist-a character he would have shrunk from-there is no more expert worker in a sort of half-veiled and elaborate humour and irony than De Quincey; but he employs those resources for the most part secondarily. Only in one instance has he given himself up to them unreservedly and of set purpose, namely, in the famous Essay on Murder considered as one of the Fine Arts,-an effort which, admired and admirable though it be, is also, it must be allowed, somewhat strained, He was a born critic and dreamer, a