e, resembling the decayed parts of the teeth
which are of a bluish cast; besides this, they are not sufficiently pure
to remain in an unchanged state, and frequently they assist in the
destruction of a tooth instead of retarding it." ("Familiar Treatise on
the Teeth," by Joseph Harris, London, 1830.)

"Tin is objectionable on account of rapid oxidation and being washed by
the saliva into the stomach, as it may materially disorder it; the
filling becomes so reduced that the cavity in which it has been inserted
will no longer retain it, and acid fruits influence galvanic action."
("Every Man his Own Dentist," Joseph Scott, London, 1833.)

In 1836 Dr. Diaz, of Jamaica, used tin foil for filling teeth.

"Gold is now preferred, though tin, from its toughness when in the leaf,
is perhaps the most suitable. Americans are superior to British in
filling." ("Plain Advice on Care of the Teeth," Dr. A. Cameron, Glasgow,
1838.)

[Illustration: FIG. 1.]

[Illustration: FIG. 2.]

"Tin foil is used for filling teeth." (S. Spooner, New York, 1838,
"Guide to Sound Teeth.")

In 1838 Archibald McBride, of Pittsburg, Pa., used tin for filling
cavities of decay.

The following facts were learned from Dr. Corydon Palmer: E. E. Smith,
who had been a student of John and William Birkey, in Philadelphia, came
to Warren, Ohio, in 1839, and among other things made the first gold
plate in that part of the country. In operating on the anterior teeth,
he first passed a separating file between them, excavated the cavity,
and prepared the foil, _tin_ or gold, in tapes which were cut
transversely, every eighth of an inch, about three-quarters of the way
across. Fig. 1 shows the size of tape and the manner of cutting. With an
instrument (Fig. 2) he drew the foil in from the labial surface, using
such portion of the tape as desired.

The instrument from which the illustration was made was furnished by Dr.
Palmer, and is shown full size. Instruments for use on posterior teeth
were short and strong, with as few curves as possible; no right and left
cutters or pluggers were used, and none of the latter were serrated, but
had straight, tapering round points, flat on the ends, and of suitable
size to fill a good portion of the cavity. He used what was termed
Abbey's chemically pure tin foil, forcing it in hard, layer upon
layer,--as he expressed it, "smacked it up." In this manner he made tin
fillings that lasted more than thirty years.

In 1839 Dr