This section is from the book "Dental Medicine. A Manual Of Dental Materia Medica And Therapeutics", by Ferdinand J. S. Gorgas. Also available from Amazon: Dental Medicine.
Sandarach is a resinous substance obtained from an evergreen tree - Thuya Articulata - which grows in the northern part of Africa. The gum is in the form of small, irregular, round and oblong tears, of a pale yellow color, sometimes brown, and more or less transparent, dry and brittle. It has a faint, agreeable odor, which is increased by warmth, and a resinous, somewhat acrid taste. It melts with heat, diffusing a strong balsam odor, and is inflammable. It is soluble in alcohol and ether, and slowly dissolves in warm oil of turpentine. It consists of three resins, varying in their relations to alcohol, ether and oil of turpentine. The sandaracin which remains after sandarach has been exposed to the action of ordinary alcohol is a mixture of two of these resins.
Sandarach was formerly employed as a medicinal agent, and entered into the composition of various ointments and plasters, but its use is now restricted to such purposes as the composition of a varnish, ingredient of incense, etc. After the erasion of ink marks, its powder, if rubbed on such a surface, will prevent fresh ink marks from spreading.
In dental practice, sandarach, dissolved in alcohol, forms a varnish for coating the surface of plaster models, etc.; it is also used for checking secretions from the gums during the operation of filling teeth, either applied as a coating to the surface, or on bibulous paper saturated with it. It is also employed to saturate cotton to be used as a temporary filling in cavities of the teeth, for the protection of medicinal applications.
Gum sandarach........ .......
Mix and digest over a moderate heat until the sandarach is dissolved.