absence of cohesion prevents the pieces from keeping their place as well
as the gold." ("American System of Dentistry," 1887.)

This is virtually saying that there is cohesion of non-cohesive gold,
and that for this reason it keeps its place better than tin. It has
always been supposed that there was no cohesion of layers of
non-cohesive gold, and as the tin is used on the non-cohesive plan,
therefore one keeps its place as well as the other. We claim that
generally in starting a filling, tin will keep its place better than
cohesive or non-cohesive gold, because it combines some of the
cohesiveness of the former with the adaptability of the latter.

"Tin will save teeth in many cases as well or better than gold. Put a
mat of tin at the cervical wall of proximate cavities in molars and
bicuspids, and it makes a good filling which has a therapeutic effect on
tooth-structure that prevents the recurrence of caries, probably because
the infiltration of tin oxid into the tubuli is destructive to animal
life. Where the filling is not exposed to mechanical force, there is no
material under heavens which will preserve the teeth better." (Dr.
Beach, _Dental Cosmos_, 1889.)

"I extracted a tooth in which I found a cavity of decay which had
extended toward a tin filling, but stopped before reaching it; on
examining the tooth-structure between the new cavity and the tin
filling, it was found to be very hard, indicating apparently that there
had been some action produced by the presence of the tin." (Dr. G.
White, _Dental Cosmos_, 1889.)

"Pure tin in form of foil is used as a filling and also in connection
with non-cohesive gold." (Mitchell's "Dental Chemistry," 1890.)

"Tin ranks next to gold as a filling-material." (Essig's "Dental
Metallurgy," 1893.)

"Tin is good for children's teeth, when gold or amalgam is not
indicated. It can be used in cavities which are so sensitive to thermal
changes as to render the use of gold or amalgam unwise, but it can only
be used in cavities with continuous walls, and should be introduced in
the form of cylinders or ropes, with wedge-shaped pluggers having sharp
deep serrations, thus depending upon the wedging or interdigitating
process to hold the filling in the cavity." ("Operative Technics," Prof.
T. E. Weeks, 1895.)

"Tin for filling teeth has been almost superseded by amalgam, although
among the older practitioners (those who understand how to manipulate
it) tin is considered one of