The first and only dental dictionary in the English language was compiled by Chapin A. Harris and published in 1849. A second edition followed, and several revisions were made by Ferdinand J. S. Gorgas, the last in 1886. Hence, for thirty-six years the dental profession has been without an up-to-date reference book of this character. The admirable work of Harris and Gorgas conformed to the requirements of their time. Dental textbooks were few, and for that reason the Harris dictionary was in the nature of a general treatise on dental subjects; various modes of practice were described, and many terms now considered nonessential to the dentist were included.

Of all the arts and sciences bearing directly upon the physical welfare of humanity none have exceeded the progress made in dentistry during the past three or four decades. New methods of practice, new discoveries, new inventions, have rapidly crowded one upon the other, so that an extensive vocabulary has come into being, and it is the aim of this work to present the advances made during all this time. There has been nothing in lexicographic- form available to guide the editor in the preparation of this volume. Not only has a considerable nomenclature developed, but it has also been constantly changing, and is even now in a transitory stage. Under these circumstances, all sources have been drawn upon. The periodical and permanent literature of our profession has been freely consulted, as well as the dictionaries of the English language and of the arts and sciences closely related to dentistry.

It would seem almost superhuman if, under these conditions, a work could have been made perfect in every particular. However, while many of the contributing and advisory staff have cheerfully assisted, and much credit is due to them, no one but the editor is responsible for any shortcomings this work may contain. Nor should it be overlooked that the lexicographer can do no more than compile and record the facts as they exist. When the profession itself is not a unit on certain terms and definitions, the compiler may not issue an authoritative dictum concerning subjects still under consideration.

As an illustration, one term among many may be cited. At a meeting of the American Dental Association recently held the term pediadontia was adopted to designate the treatment of children's teeth. At the same time and in the same city the American Society of Pediadontists adopted the term pedodontia and changed its name accordingly. Under the circumstances preference should be given to' the term adopted by the specialists. On the other hand the term apicoectomy has been generally adopted to designate the operation of excising the apex of the root of a tooth; however, this does not authorize the lexicographer to omit apectomy, apicectomy, apiceotomy, apicotomy, apiectomy and apioectomy, all of which have been used and have appeared in dental literature. When the profession agrees on any term definitely, the preferred term will be given as such in future editions, and the discarded, incorrect or obsolete term will appear merely for information - and reference for the student who may be looking up some particular subject in our literature.

A number of terms to designate the disease so generally known as pyorrhea have been suggested as preferable by authorities of equal merit. The- American