memorialized as the 'Father of Modern Dentistry' by the American Dental Association in the inscription on a monument in Lincoln Park, Chicago, in 1918. His scientific researches in anatomy, bacteriology and pathology revolutionized the practice of operative dentistry from 1895 to 1915.

Until comparatively recent years the practice of dentistry consisted for the most part in reparative service-filling cavities, replacing lost teeth and other technical procedures in treatment of diseased oral structures. As the vastly important health relationships of the dental field became more definitely recognized, methods of practice gradually changed, placing all technical service on a basis of preserving normal function of the oral tissues, while preventing those conditions which menace health.

The teaching of clinical dentistry is divided into a number of branches: (1) Preventive or prophylactic dentistry, meaning the practice of preventive measures by the dentist and the advising of patients in oral hygiene; (2) operative dentistry, consisting mainly of reparative measures, such as fillings, inlays, etc.; (3) oral pathology and therapeutics, treating diseases of the soft tissues of the mouth and especially the gums and dental pulp; (4) orthodontia, concerned with the correction of irregularities of the teeth and concurrent malformations of the jaws and inharmonious development of the lower half of the face; (5) crowns and bridge work, which includes those procedures by which crowns are placed on the roots of teeth, or bridges are constructed to replace one or more lost teeth, held in place by attachments to adjacent teeth; (6) denture prosthesis, or substituting an artificial appliance replacing all, or a considerable number of lost teeth; (7) oral surgery, which considers the treatment of mouth, jaws and adjacent structures.

History. Some forms of dentistry seem to have been practised in ancient Egypt, Etruria, Greece, and Rome. In the Middle Ages the art made little progress, except among Arabian physicians. It was revived as a serious study in the eighteenth century, when Fauchard published Le Chirurgien Dentiste (1728). The literature on the subject was of slow growth; but in 1826 Koecher's Principles of Dental Surgery (London), established dentistry as a science.

In the United States, dentistry was introduced by a Frenchman named Le Mair, during the Revolutionary War; and about 1788 John Greenwood established himself in New York as the first American dentist.

The birth of dentistry as a distinct profession may be dated from the incorporation in 1839 of the Baltimore College of Dental Surgery, the first dental college in the world. Other colleges followed, and local dental societies were founded in various parts of the country. The first national dental association, known as the American Society of Dental Surgeons, was organized in New York City in 1840; and in 1855 the national convention of dentists was inaugurated. The pioneer dental periodical, the American Journal of Dental Science, was first issued in June, 1839.

Bibliography.-On

PREVEN

TIVE DENTISTRY consult Fone, Mouth Hygiene, a Text Book for Dental Hygienists, and Preventive Dentistry for Dental Students.

On OPERATIVE DENTISTRY consult Black, Operative Dentistry (2 vols.); Johnson, Text Book of Operative Dentistry; Kirk, American Text Book of Operative Dentistry; Marshall, Principles and Practice of Operative Dentistry.

On ORAL PATHOLOGY consult Black, Special Dental Pathology; Burchard and Ingliss, Dental Pathology and Therapeutics; Prinz, Dental Materia Medica and Therapeutics; Long. Dental Materia Medica, Therapeutics, etc.

On ORTHODONTIA consult Angles' System of Orthodontia; McCoy's Applied Orthodontia.

On PROSTHETIC DENTISTRY consult Turner, American Text Book of Prosthetic Dentistry; Wilson, Dental Prosthetics; Prothero, Prosthetic Dentistry; Richardson, Mechanical Dentistry; Warren, Mechanical Dentistry and Metallurgy; Evans, Artificial Crowns and Bridge Work; Goslee, Principles and Practice of Crown and Bridge Work.

On ORAL SURGERY consult Blair, Surgery and Diseases of the Mouth and Jaws; Brophy, Oral Surgery.

Consult also Fischer, Local Anesthesia in Dentistry; Raper, Radiodontia; McCoy, Dental and Oral Radiography; Ivy and Ennis, Interpretation of Dental and Maxillary Roentgenograms; Simpson, Technic of Oral Radiography; Noyes, Text Book of Dental Histology and Embryology; Black, Anatomy of Human Teeth; Broomel and Fischel, Anatomy and Histology of the Mouth and Teeth.

Den'ton, town, Lancashire, England; 7 miles southeast of Manchester. Industries include felt hats, cotton yarn, wire, bicycles. Here are the reservoirs of the Manchester waterworks. Pop. (1921) 17,620.

Denton, city, Texas, county seat of Denton county, on the Texas and Pacific and the Mis

souri, Kansas, and Texas Railroads; 35 miles northwest of Dallas. It has flour and cotton mills and grain elevators. Pop. (1920) 7,625; (1930) 9,587.

D'Entrecasteaux, dän'tr'kästo', group of British islands in the Pacific Ocean, lying to the north of the extreme east end of New Guinea, with which they are included for administrative purposes. The chief are Fergusson, Goodenough, and Normanby Islands. The total area of the group is 1,200 square miles.

Dentures. See DENTISTRY. Den'uda'tion, in geology, the laying bare of the rock formation by the removal of superficial matter as the result of erosion (q.v). It also signifies the process by which the earth's surface is broken up and the loose material carried away.

The chief agents of denudation are: rain, which washes away the finer components of the soil, and dissolves some forms of rock; the heat of the sun, which expands rock to a point of disintegration; frost, which rends open rock seams in which moisture has collected; wind laden with sand, which abrades even the hardest cliffs; the rush of streams and rivers; glaciers, which grind, furrow, and smooth the rock over which they flow; and the sea, which is continually wearing away the rocks along the coast. Plants and animals also aid the former by the expansive action of roots in rock crevices; the latter by borings, burrowings, etc.

The rate of denudation depends on the declivity of the ground, the nature of the subjacent rocks, and the rigor of the climate. As denudation advances the land forms tend to alter. The general level is lowered, the features lose their relief, and the diminishing gradients check the rapidity of the process. The student of natural scenery can distinguish in this way between a new country, recently uplifted, in which the characteristic effects of erosion are not yet fully developed-as in the canyons of the Western United States-and a mature country in which all the varieties of surface form characteristic of the structural type to which the land belongs are fully developed -as in the Appalachian region. Finally, there is a senile type of landscape, on which erosion has operated so long that modelling has practically disappeared, and the surface has approached a dead level.

Attempts have been made to estimate the rate at which the surface of land is reduced by denudation. As the sediment which a river carries to the sea represents losses from its basin and tributaries, then it is obvious

that if we could correctly estimate the amount of sediment transported to the sea by the rivers of any given area, we should at the same time ascertain the rate at which that area is denuded. Observation has shown that this denudation proceeds more rapidly in some regions than in others-therefore the work of no individual river can be taken as a standard by which to estimate the general rate of erosion all the world over. Much depends on physical and climatic conditions, and much on the geological structure of a country and the composition of its prevalent rock masses. Thus, the Mississippi is said to remove from the general surface of its basin one foot in 6,000 years, the Rhone one foot in 1,528 years, the Po one foot in 729 years. To the matter mechanically suspended in the water or swept forward on the beds of rivers we have to add the matter carried in solution, which in many rivers is very considerable. Rivers like the Rhine, the Danube, the Elbe, and the Rhone are said to contain in every 6.000 parts by weight one part of dissolved mineral substance. See GEOLOGY; MOUNTAINS; RIVERS.

The importance of denudation was first insisted on by James Hutton in his Theory of the Earth (1795), and eloquently expounded by his pupil, Playfair, in his Illustrations of the Huttonian Theory (1802). Their work was ably seconded by Lyell, Scrope, and Darwin, and their theories accepted by all geologists. Consult also Geikie, Earth Sculpture; Chamberlin and Salisbury, Geology; J. Joly, Surface History of the Earth (1925); E. Suess, Face of the Earth (1903); Lake & Rastall, Textbook of Geology (1927).

are now

Den'ver, capital and largest city of Colorado, coextensive with Denver county, is situated on both banks of the South Platte River; 922 miles northwest of St. Louis, and 1,457 miles northeast of San Francisco. It lies on a level plain, 5,280 feet above sea level, beyond which rise the snow-capped peaks and deep blue shoulders of the Rocky Mountains. Seven major railroads enter the city, the Union Pacific, the Chicago, Rock Island and Pacific, the Denver and Rio Grande Western, the Chicago, Burlington and Quincy, the Denver and Salt Lake, the Atchison, Topeka and Santa Fé and the Colorado and Southern. The climate is dry and equable, and the air clear and invigorating with abundant sunshine. The rainfall averages between 14 and 15 inches yearly, and the mean annual temperature is

Burton Holmes, from Ewing Galloway
Sixteenth Street, State

irrigated country and vast grazing ranges. Its boulevards and parkways are a source of pride. There are 35 improved parks and many playgrounds, with tennis courts, baseball diamonds, and handball courts. Washington and Berkeley Parks each have a municipal bathing beach. The Civic Centre was planned by Frederick Law Olmstead on land valued at $1,700,000. Denver is the gateway to 14 national parks and 32 national monuments. The city has its own mountain parks system which begins 12 miles from the city and extends

for 30 miles to the summit of the Rocky Mountains. A main circle drive connects the parts of this system, winding up Lookout Mountain, along the mountain tops, in public camps and picnic grounds, through a municipal game preserve containing bison, elk, and deer, to the sum

Capitol in the Distance

mit of Mt. Evans (14,259 feet high), to Red Rocks Park.

Denver has a splendid group of public edifices. On 15 acres in downtown Denver is the State Capitol, built of Colorado granite, at a cost of $2,800,000 and containing one of the most complete law libraries in Western United States. To the south is the State Museum of Indian and pioneer relics; to the north is the State Office Building, costing $480.000. On 191⁄2 acres stands the Colorado School of Medicine and Hospitals (cost $2,300,000). composed of the School of Medi

cine and School of Nursing of
the University of Colorado, and
the Colorado General Hospital
and the Colorado Psychopathic
Hospital (free). Denver has
been called the Federal Capital
of the West because here are
located more separate and dis-
tinct establishments of the Fed-
eral Government than can be
found in any other place out-
side the nation's capital. They
are located in the Denver Fed-
eral Post Office and Court House
(cost $2,577,000), the U. S.
Custom House ($1,000,000), and
the Mint, a replica of the Bank
of Florence and one of the three
U. S. mints (cost $1,500,000).
In 1932 the City and County
Building was completed (cost
$5.000,000). It covers a city
block opposite the State Capitol,
facing 30 acres of open park.
The Municipal Auditorium seats
12,000 people. There are many
fine business buildings.

The public school system is
one of the best, consisting of
elementary schools, junior high
and high schools, a school for
the deaf, and an opportunity
school which is unique in that it
has no age limit, no entrance re-
quirements, is free, and offers a
wide range of practical subjects.
Higher education is represented
in the University of Denver
(q. v.), Colorado Woman's Col-
lege. Regis College, Iliff School
of Theology (Methodist), St.
Thomas Seminary (R. C.), and
Loretto Heights College. There
are many special schools such
as business, music and art in-
stitutions. The University of
Colorado has its medical school
here.

There is a public library with
13 branches and an exceptionally
fine engineering library. Denver
has an unusually large number
of churches of all denominations.
The more noteworthy are the St.
John's Cathedral (Episcopal),
the Cathedral of the Immaculate
Conception (Roman Catholic),
and the First Church of Christ,
Scientist.

The municipal unit for charitable healing consists of Denver General Hospital, Steele Detention Hospital for contagious diseases, and the Tuberculosis Pavilion. The General Hospital houses the City's department of Health and Charity and operates the Colorado Training School for Nurses. At Denver are the State Industrial School for Girls and the State Home for Dependent and Neglected Children. Industries. As the largest city between the Missouri River and the Pacific Coast, Denver is an important distributing centre. It has an inexhaustible supply of fuel for all purposes -coal from nearby fields (lig

nite, bituminous, and anthracite), natural gas piped from Texas, and fuel oil from nearby refineries. The neighborhood produces about 250 useful minerals. Gold, silver, lead, copper and zinc mines create a large smelting industry. The Denver Union Stock Yards occupy 130 acres. Denver has been noted for its manufactures of mining machinery and foundry supplies. There is no dominant industry but many flourishing ones, notably meat packing, canning, and manufactures of rubber goods and automobiles. There are railroad repair shops.

Denver's municipal

airport

was the second in the United States to receive the highest rating of the Department of Commerce. The Moffat Tunnel through the Continental Divide, places Denver on a direct transcontinental line.

Population.-Denver's population was 35,629 in 1880; 106,713 in 1890; 133,859 in 1900; 213,318 in 1910; 256,491 in 1920; and 287,861 in 1930.

Government.-Denver is a 'Home Rule' city. City and County offices are combined. After experimenting with various forms of government, Denver adopted a combination of Mayor, Manager, and Commission forms with a mayor, auditor, and city council exercising executive, administrative and legislative powers respectively.

History. The site of Denver was settled in 1858 under the name of St. Charles, which was later changed to Denver. In 1859 a city government was organized, and in 1868 Denver became the capital of the Territory. Between 1894 and 1897 the towns of Barnum, Colfax, Harmon, and South Denver and the city of Highlands were added to Denver's area; in 1902 the city limits were extended to include Argo, Berkeley, Elyria, Globeville, Montclair and Valverde, and the city and county of Denver was chartered.

Commission government was adopted in 1913 but abandoned in 1916. In 1918 the city decided to purchase its water supply system. In that year a new charter was written. In 1928 the pipe line bringing natural gas from Texas to Denver went into operation. In 1932 a loan from the RFC made possible the building of the Dotsero Cutoff -175 m. of railway to Salt Lake City through Moffat Tunnel.

Denver, University of, a co-educational institution in Denver, Colorado, was founded in 1864 by the Methodist-Episcopal Church as Colorado Seminary,

and was reorganized under its present title in 1880. The University includes a College of Liberal Arts, Graduate School, Summer School, School of Law, School of Dentistry, School of Commerce, Accounts, and Finance, School of Science and Engineering, School of Librarianship, Chappell School of Art; the Foundation for the Advancement of the Social Sciences, and the University Civic Theatre. Included in the College of Liberal Arts are the Extension Division and the Division of Education and Psychology. Situated in University Park are University Hall, the chapel, gymnasium, library and the Chamberlin Observatory with a 20-inch refractor telescope.

Deoband, de'ō-bund or dā', town, Saharanpur district, United Provinces, India; 45 miles north of Meerut, much frequented by pilgrims on account of its numerous temples. There is trade in grain, sugar, and oil. Pop. (1931) 22,126.

Deodand, de'o-dand, English law term, now obsolete, denoting an animate or inanimate chattel which had been the cause of the death of a human being. It or its value had to be offered to God (Deo dandum) in order to appease His wrath. This was done by declaring it forfeited to the king, who applied the proceeds to pious uses. The most frequent deodands were such things as horses, boats, carts, etc. It was quite immaterial that the chattel was the property of the deceased. As late as 1840 a railroad engine was declared deodand, and the company had to pay $10,000 as the value thereof. In 1846 the whole law of deodand was abolished by statute in England. The law has never existed in the United States.

Deodar, de'ō-där, the common name of the Indian cedar (Cedrus deodara), a large and handsome tree attaining a height of 150 to 200 feet, found in Northwest India and the Himalayas. The timber is exceedingly valuable.

Deo'dorizers are substances employed for the purpose of absorbing or destroying the odoriferous principles evolved from decomposing matter. Freshly burned charcoal is a powerful deodorizer. See ANTISEPTICS; DISINFECTANTS. Deogarh, or

BAIDYANATH,

town, Santal Paraganas district of Behar and Orissa, India. It has a group of 22 Hindu temples dedicated to Siva, visited by pilgrims from all parts of India. D'Eon de Beaumont. See EON DE BEAUMONT. Deontology, a term for the science of duty, ethics.

Deori, town, Central Provinces, India; 60 miles northwest of Jabalpur. Pop. (1931) 5,638. Deoxida'tion, a term applied to the process of withdrawing the oxygen from a compound, as in the reduction of peroxide of iron in the smelting furnaces to the condition of metallic iron. Deoxidation may be carried on before the blowpipe, where the inner flame is essentially a deoxidizing one.

Department, in a political sense, a division of government, or territory. In the United States the term is used to designate the larger governmental divisions, as Department of State, Department of the Interior, etc., each under the direction of a Secretary, who is er officio a member of the President's Cabinet. The term is also applied to subordinate divisions of the army organization, as Ordnance Department, Medical Department, etc.; and to the territorial distribution of the army, as Department of the East, Department of Luzon, etc.

In Great Britain the term department is applied to the subordinate divisions of the great branches of administrative offices, as the Bankruptcy Department of the Board of Trade.

In France the term denotes a primary territorial division, practically equivalent to the cantons of Switzerland or the States of the United States.

Department Stores sell many classes of merchandise, each in a separate department under separate management and rendering separate accounts. Every phase of a department store's operations is figured in terms of the individual department. These stores possess many advantages: great purchasing power, the services of men of outstanding ability, a first-class organization for the buying, selling and dispatch of goods, greater sales attraction. Their greatest danger lies in high operating expense and that they may become machine-like and impersonal in dealing with customers. To offset this lack, the buyer for each department becomes a substitute for the proprietor, and may exercise a great influence in his individual department. Historians mention the Bon Marché of Paris as the beginning of department stores, and in New York, they go back to 1874 when L. Straus & Son first sold dry goods and house furnishings under one roof in the rented space of the little Macy store's basement. Any one of a dozen New York department stores does a yearly business of about $80.000.000.

Depar'ture, in nautical sci

ence, the easting or westing which a vessel makes from the longitudinal meridian passing through its starting point. It is measured along a parallel of latitude, and is (mathematically) the product of the sine of the angle of the course by the straight-line distance sailed.

a

DePauw University, de-po', Methodist-Episcopal college founded in 1837 at Greencastle, Ind., by the Indiana Conference. In 1884 its name was changed from the Indiana Asbury University in recognition of the munificence of Washington C. DePauw, who endowed it by his will. At various times schools of law, medicine, divinity and art have been instituted, but lack of funds has made it unwise to continue them, and the university now consists only of the Asbury College of Liberal Arts and the School of Music. See COLLEGES.

are

Dependent Children normal children who require to be supported by other than their own parents. Insane. dumb, or otherwise defective children are not included.

The child-placing movement in the United States began in 1619, when the Mayor of London sent to the Virginia Company 100 children to be placed with 'honest and good masters,' but until the nineteenth century there was no organized plan of placing children in family homes, and there were no societies devoted to this specific work. The pioneer of the organized childplacing movement was Charles Loring Brace, who in 1853 organized the New York Children's Aid Society and began sending children to western homes. Since that date many of the States have instituted similar societies. In 1873 Michigan opened a State school for dependent children at Coldwater, the law providing that it should be only a temporary home while the 'child is on its way to its own place in the family.' This system was adopted by Minnesota, Wisconsin, Colorado, and other States.

Children may be placed out in private families to board, the board being paid by the parents, in whole or in part, or from the public treasury, or from the treasury of some private organization; or they may be placed out in 'free homes' without payment of board, with or without legal adoption. The old practice of placing out children on an indenture contract, under which the foster parent assumed certain obligations as to food, clothing, schooling, etc., agreeing further to pay a stipulated sum to the child on the expiration of the contract hardly exists now.

The orphan asylum system was long preferred in the United States. The arguments in favor of these institutions are that in them environment can be controlled, children requiring special care can receive it, sanitary conditions can be made perfect, education can be supervised, and the most helpful and elevating influences can be exerted, brothers and sisters need not be torn apart; when only temporary care is required, the dependent child does not form emotional attachments outside his home as is the case when he goes to a foster home. On the other hand, serious students of the problem are nearly unanimous in agreeing that institutional life is contrary to child nature and, therefore, undesirable. In Russia, where dependent children are under the commissariats of health and education, institutions are operated on a large scale. But even in Russia there is a tendency to recognize the value of foster homes or home care over the mechanical routine of institutions.

Mothers' pensions or public aid to widows is now provided in most States of the United States, since it is recognized that dependent children are best cared for in their homes by their mothers. Private and public charities are adopting this practice also. Where the conditions in the child's own home are definitely bad, the foster home is regarded as the best substitute for it. The institution, however, still predominates. The individual child needs the attention of an expert case worker to determine the method of care best suited to its needs.

In connection with this subject see also CHILDREN'S BUREAU; CHILDREN'S COURTS; FOUNDLING HOSPITALS; CHILDREN, LEGISLATION IN BEHALF OF; CHILDREN, DELINQUENT; CHILDREN, CRUELTY TO; CHILDREN'S AID SOCIETIES; CHILDREN'S HOME SOCIETIES.

Consult the Report of the White House Conference on Child Health and Protection (1930); H. W. Thurston, Dependent Child (1930); E. L. Trotzkey, Institutional Care and Placing Out (1930).

DePere, de-per' or de-pår', city, Brown county, Wisconsin, on the Fox River, and on the Chicago, Milwaukee, St. Paul and Pacific and the Chicago and Northwestern Railroads; 5 miles southwest of Green Bay. It has manufactures of boats, barn equipment, paper, knit goods, and foundry and supply factories. It is the seat of St. Norberts College (R. C.). Pop. (1930) 5,521.