force the same as cohesive gold; if non-cohesive
gold is used, the strips can be folded into mats or rolled into
cylinders, and are used on the wedging plan, the same as non-cohesive
gold, or the strips can be folded back and forth in the cavity until it
is full.

(_b_) Lay a sheet of non-cohesive gold, No. 3, on a sheet of tin of the
same number, cut off strips, roll into ropes and use as non-cohesive
gold. It is easily packed and harder than tin, and has a preservative
action on the teeth. Line the cavity with chloro-balsam as an insulator
against possible currents and moisture; especially should this be done
in large cavities or chalky teeth.

(_c_) A sheet of non-cohesive gold, No. 4, is laid on a sheet of tin of
the same number, cut into strips and rolled into cylinders, or folded
into blocks, always in equal portions; then they will unite to the
extent of two leaves. These fillings sometimes become a solid mass about
the color of amalgam, and last very well, as the metals have become
united by electrolysis. An excess of tin will be marked by lines or pits
in the filling, showing where the tin has been disintegrated or
dissolved by the chemical action which occurs on the surface exposed to
moisture.

No doubt, good fillings have been made by the above methods, yet some
were granular, gritty, and were easily removed, while others were quite
smooth and hard; probably in the first instance the proportion of tin
and gold was not proper,--that is, not equal; or it was not well
condensed. Tin being the positive element, it is more easily acted on
and disintegrated by electrolysis (chemical action of the fluids).

When this combination does become hard, it wears longer than tin on an
occlusal surface, but we believe that in some cases where it was used
the teeth could have been saved just as well with either tin or gold, or
by filling part of the cavity with tin and the rest with gold.

If tin foil is laid on 22-carat gold and vulcanized, it becomes
thoroughly attached and will take a tin polish; the attraction or
interchange of atoms takes place to this extent.

This combination of tin and gold can be used at the cervical margin, or
a cavity can be lined with it, and the remainder filled with cohesive or
non-cohesive gold.

"Tin and gold (Tg) folded or rolled together in equal portions possesses
a greater number of desirable properties than any other material, for it
is easily adapted, has antiseptic action and