properties and uses of tin
foil; this information has been sought to be given in the simplest form
consistent with scientific accuracy. The present use of tin is a case of
the "survival of the fittest," because tin was used for filling teeth
more than one hundred years ago. There is not a large amount of
literature upon the subject, and no single text-book has treated the
matter fully enough to answer the needs of both teacher and pupil. It is
difficult for the student to collect and harmonize from the many
different sources just the kind and amount of information required for
his special use. Perhaps this work will be of assistance to scientific
students and practical operators in the art of using tin foil, including
all who wish in compact form an explanation of the facts and principles
upon which the art is based. A good method to arouse in students an
interest in the use of tin foil is to have them use it in operative
technics, which is becoming an effective adjunct in every dental
college. By this means a great factor will be brought to bear, and the
result will be that hundreds of graduates every year will begin
practice better qualified to save teeth than if they had not known
whatever may be learned about this material. At the University of
Pennsylvania, Department of Dentistry, session 1896-97, out of the total
number of fillings made in the clinical department (fractions omitted)
55 per cent. were gold, 15 per cent. tin, 10 per cent. amalgam. This
shows that tin has some very strong friends in the persons of Professors
Darby and Kirk.

The historical sketch of the development of the subject is arranged in
chronological order, and is given partly to show that some old ideas and
methods were good, and some obviously incorrect when viewed in the light
of more recent developments. Part of the history will be new to the
oldest members of the profession, and the younger ones will certainly
read it with interest. The work has been brought up to date by
considering all the properties and methods available. More names, good
opinions, and dates could have been given, but the writer believes that
what is herein presented is enough to thoroughly substantiate his own
opinions, experiments, and practical applications. Some of the
illustrations have been made especially for this work; the others have
been obtained through the courtesy of the owners.

"Let not the foggy doctrine of the superiority of gold in all cases act
o