twice around the tooth and drawn only closely enough to turn the edges of the rubber upward on the neck of the tooth, thus avoiding pain as much as possible, tying firmly with a square or a surgeon's knot.

Should the ligature be impracticable or inconvenient, apply,

with the clamp forceps, one of the numerous rubber-dam clamps.

To confine the lower portion of the rubber, attach a second dam-holder to the lower corners, allowing the band to pass

around the back of the neck, as in Fig. 72. Weights are also

used for this purpose.

Having the rubber dam thus adjusted, place in position the mouth-piece of the saliva-pump, and the work will be kept dry and the patient comfortable.

In some cases the clamp may be applied to the tooth first and the rubber stretched over it and the silk applied. This may be readily done if the hole in the rubber is made a little larger than usual.

An assistant, if at hand, may, with an instrument, hold the rubber down on the neck of the tooth while the silk is applied.

When the silk is to be applied far back in the mouth, it

may be wound around the little finger of each hand and with the forefingers carried back and pressed down between the teeth.

GOLD FOR FILLING.

Gold is the most elegant material for filling teeth that we possess, and for most cases it is the best. Though not the color of the tooth, it receives and retains so fine a polish that it is less objectionable than any other material.

Gold is prepared in two forms--foil and crystal or sponge gold. Foil is used cohesive and non-cohesive. Non-cohesive foil is so prepared that it will not cohere when the surfaces are brought in contact. Cohesive foil is prepared by annealing so that the particles will cohere when the surfaces are brought in contact, and it may thus be welded into a solid mass while cold. For instance, two sheets of foil, well annealed, laid together and pressed by passing over them a paper-folder, become united as one sheet.

Most of the non-cohesive foil now made may be rendered cohesive by annealing.

A sheet of gold foil is four inches square. It is numbered according to its weight, a sheet of No. 3 weighing three grains; of No. 4, four grains, etc. A book is one-eighth of an ounce. Foil is used of various thicknesses, from No. 2 to No. 120, or thicker. Gold in Nos. 20 to 240 is prepared by rolling, while foil thinner than No. 20 is made by beating the rolled gold to the required thinness.

Gold foil may be prepared for use in various forms, as the rope, the tape, the mat, the compact and the loose block, the compact and the loose cylinder, and the ribbon.

For use cohesively, cut the foil into strips of one-fifth or one-fourth of a sheet, and roll into ropes with a napkin, or, better, with the Adams roller, then cut into pieces one-fourth of an inch or more in length, according to the convenience of the operator and the requirements of the case.

For rolling the foil, take a large napkin or fine towel and fold lengthwise to a width of four or five inches, then fold this once upon itself, and, placing the strip of foil in the fold, by a dexterous movement of the upper portion of the napkin upon the lower it may be rolled into a rope.