ion made to overcome the resistance of occlusion. The teeth are
cushioned in the jaw and yield under pressure. The elasticity of the
substance of which the teeth are made is well understood. Ivory is the
most elastic substance known. The teeth coming together is like the
percussion of two billiard balls. Now a filling to save the teeth should
correspond as nearly as possible with the tooth-substance; it should not
be arbitrary, but elastic and yielding. Tin is interdigitous; it expands
laterally, and is almost as easily introduced as amalgam, and when put
in place does not have to be bound to be retained. Tin, with an outside
covering of gold to protect it, makes a filling to which amalgam bears
no comparison. In the light of scientific investigation there can be but
one method--a method based upon the recognized principle that the
_filling-material_ and the _manner_ of _introducing_ it shall correspond
to and be in harmony with the living, vital organism with which it comes
in contact.

"After excavating, the cavity is treated with absolute alcohol, as
cleanliness and thorough dryness are absolutely essential.

"The _tin_ is put in with steel pluggers, after the method of wedging;
it must be thoroughly condensed, so as to leave a smooth surface, and
enough used to come up to where the enamel and dentin join.

"The effect is not produced by incorporating or interlacing the gold
with the tin; we rely upon the affinity of the two metals to retain the
gold; no undercuts, angles, or pits are made in the tin, dentin, or
enamel. The gold, extra cohesive from No. 4 to 40, is made to adhere to
the tin by simple contact, without pressure or force; the union is not
mechanical.

"The instruments used for filling the remainder of the cavity with gold
are Shumway's ivory points, which adapt the gold nicely to the margin.

"The set consists of five and were patented in 1881, and have been used
by me since that time for manipulating cohesive gold. One 'point' is for
proximal cavities in the anterior teeth; three 'points' of different
sizes are for occlusal cavities; one 'point' for proximal cavities in
bicuspids and molars and labial and buccal cavities; the sides, edges,
and ends of the 'points' are used, as the purpose is simply to obtain
contact.

"The 'point' shown full size in Fig. 8 is of more general application
than any of the others, and is used for proximal cavities in bicuspids,
also labial and buccal cavities. The ha