means of mouth sanitation and the practical utility of the latter in maintaining the physical efficiency of the fighting personnel, with the result that definite a,nd active work has been undertaken to extend these health benefits to civilian populations.
Undoubtedly the most notable example of comprehensive planning for the national extension of dentistry and oral hygiene as a factor of the public health service is that proposed in the Interim Report on the Future Provision of Medical and Allied Services, made to the British Ministry of Health by the Consultative Council on Medical and Allied Services, May 1920. This report recognizes oral hygiene and dental service as factors of public health and as proper subjects for control and development by the State. Oral hygiene compre- hends much more than the correction of dental defects and oral infection due to neglect of the tooth brush; its aim is prophylactic as well as corrective. Corrective procedures such as the filling of cavities of decay, treatment of diseased roots, extraction of useless teeth, correction of irregularities in their position and prosthetic restoration of lost teeth or parts of teeth, merely arrest the progress of disease and mechanically restore damage already done. The entire energies and skill of the whole dental profession are totally inadequate to cope with more than a small fraction of the corrective work needed. To establish the habit of personal care of the mouth in school children is a field of activity that has developed the special- ly trained dental nurse or hygienist as an adjuvant to dental serv- ice, whose calling is now legalized in the principal states of the United States. The work of the dental nurse is limited to the surface treatment of teeth, in the removal of deposits and accretions thereon, the training of school children in the systematic use of the tooth brush and their education in the importance of mouth cleanliness. In addition to the physical benefits resulting from oral hygiene among school children there is also a manifest improvement in moral. A child who has learned to use the tooth brush exhibits increased self-respect, greater attention to bodily and mental cleanliness, closer compliance with school regulations and an awak- ened interest in attendance and studies. The close connexion be- tween oral hygiene and better citizenship is no longer debatable, and the present trend is toward making dental and oral hygiene service in all civilized countries a public health measure.
The many head, face and jaw wounds during the World War created a new field for oral surgery and surgical prosthesis. For the successful treatment of these cases it became evident that surgical measures alone were insufficient, as the loss of tissue from gunshot wounds of the head and face, as well as the unsightly scars resulting from extensive lesions when surgically treated, left the patient in many instances with repulsive deformities. The resources of surgery and dentistry were called into cooperation. Plastic surgery, in- volving the transplantation of the soft tissues and of bone to supply missing parts, was developed to a degree previously unknown. The rebuilding of the face, including reconstruction of the nose, lips, cheeks, the orbicular region, etc., was accomplished with a perfection in many cases almost miraculous. In this work the aid of dental prosthetic technique was often necessary. The large and in- creasing number of casualties of the head, face and jaws resulting from trench warfare quickly developed the need for hospitals and specialized equipment devoted entirely to the treatment of this class of wounds. Of these centres of specialized surgical activity the fore- most in importance and extent was Queen's hospital, Sidcup, Kent, England, a unit under British administration with sections for British, Canadian, New Zealand and Australian forces manned by personnel from the respective forces. Cooperation between the medical and dental staffs of the sections was organized with most satisfactory results. The American Ambulance hospital of Paris at Neuilly-sur-Seine, subsequently taken over as American Red Cross hospital No. I., was an analogous centre of specialized head, face and jaw surgery in which similar cooperation was again successful. These experiences furnished convincing evidence of the need by each profession of a more intimate acquaintance with the work of the other. This need is recognized in the practice of adding a professional dental service to hospital staffs.
A general quickening of scientific research has followed. Bac- teriological and histological investigation of dental and oral pathol- ogy by numerous investigators has not only added greatly to knowledge in this field, but brought about great improvement in dental and oral surgical technique. Notable progress has been made in the study of dental and oral infections and of physical irritations of nerve terminals in and about the teeth, in their relation to mental disorders and reflex neuroses, that cause disturbances of the special sense organs as well as spastic disorders of a local or general char- acter. Attention has been directed to the endocrine relationships of the teeth and oral tissues, especially as to the probable connexion between the activities of the ductless gland system and the reactions of the salivary secretion, as well as to variations in the calcified structures of the teeth and their susceptibility or immunity to caries. Corresponding changes in the objectives as well as in the character, the content and extent of dental education have taken place in harmony with these developments. Practical teaching has tended toward a closer approximation to the fundamental ideals and meth- ods of general medicine in so far as they represent the principles common to the whole science and art of healing. While the most conspicuous progress in dentistry during the decade 1910-20 has been in the direction of its vital and hygienic relations, its technical and engineering features have shown a similar development. Until this period the construction of artificial dentures for the prosthetic restoration of lost teeth was almost wholly an empirical procedure depending on the judgment, manual skill and good taste of the opera- tor. Scientific studies of the engineering principles underlying the mechanism of the human masticatory function, initiated about 1890 by W. G. A. Bonwill. of Philadelphia, and since prosecuted by his numerous followers, have brought the knowledge of masticatory movements and of the relations of the teeth and their morsal surfaces thereto to a state of completeness that enables the prosthetist by the aid of mechanical articulating devices to reproduce in the artificial denture a mechanism with possibilities approximating, both functionally and artistically, those of natural dentures.
The work of Alfred Gysi, of Zurich, constitutes the most advanced achievement in this field. In close relation to the progress is the co5rdinate progress made in the artistic reproduction in porcelain of nature's forms and colouring, brought about mainly by the studies of J. L. Williams, of New York, and N. S. Esdg, of Philadelphia.
In 1913 Charles H. Mayo, the distinguished surgeon of Rochester, Minn., expressed the opinion that the next great step in medical progress in the line of preventive medicine should come from the dental profession. A review of the progress since made would seem to indicate a reasonable prospect of the fulfilment of that prophecy.
(E. C. K.)
DEPEW, CHAUNCEY MITCHELL (1834- ), American lawyer and politician (see 8.56), failed of reelection as U.S. senator on the expiration of his term in 1911. In 1914 he favoured the repeal of the Panama Canal Tolls bill. He assailed pacifism and after the sinking of the " Lusitania " (1915) urged a strong stand against Germany. In 1918 he presented to Peekskill, N.Y., a bronze statue of himself, which was erected in Depew Park, a plot of land purchased from the Indians in the I7th century by an ancestor, Francois du Puy. In 1919 he added much adjoining land to this park.
He is the author of Some Views on the Threshold of Fourscore (1914), including speeches delivered 1912-14, and Speeches and Literary Contributions at Fourscore and Four (1918, articles and speeches composed 1916-18).
DERBY, EDWARD GEORGE VILLIERS STANLEY, 17TH EARL OF (1865- ), English statesman (see 8.69), was in Jan. 1915 created a Knight of the Garter. In Oct. 1915 he became director of recruiting for the army, and as such was re- sponsible for a new scheme for a final effort on behalf of voluntary service. A large number of recruits were obtained by Lord Derby's scheme, but as the numbers did not equal expectations the Military Service bill was introduced and carried in Jan. 1916. In Feb. 1916 Lord Derby became chairman of the naval and military air service joint committee, but resigned in April, becoming Under-Secretary of War in July. On the formation of Mr. Lloyd George's Government in Dec. 1916, he became Secre- tary of War, and in April 1918 was appointed British ambassador to France. He retired from the latter office in Nov. 1920.
DEROULEDE, PAUL (1846-1914), French author and poli- tician (see 8.74), died at Mont-Boron, near Nice, Jan. 30 1914. In 1910 he had published a collection of his patriotic speeches, and a volume La Ligne des Patriotes containing further extracts from them appeared two years after his death.
DESCHANEL, PAUL EUGENE LOUIS (1856- ), French statesman (see 8.91). During his absence from the presidential chair in the Chamber of Deputies after 1902, Deschanel carved out for himself a position of some political importance on the Committee of Foreign Affairs. He was president of this important committee when the Franco-German treaty of 1911, confirming the settlement of the Agadir incident, came before Parliament. He was reelected deputy in 1910, and on May 23 1912 he was chosen to succeed M. Brisson in the presidency of the Chamber of Deputies. He was maintained in this office by subsequent ballots in 1913 and 1914. His presidency of the Chamber was marked by much oratory of a literary nature, and by considerable dexterity in the treatment of the rowdy elements of the extreme Right and the extreme Left. He aimed at being the impartial Liberal Republican. During the World War he played a great part as the national orator. There were, indeed, few occasions of sorrow or of thanksgiving which his eloquence did not either lighten or intensify. He delivered orations more frequently than he made speeches. Whether it was to hold Ger-
