To restore to blackened teeth their whiteness, Galen advises them to be rubbed with special medicaments, one of which is made up of dried figs, burnt and pounded, with spikenard and honey. He gives, besides the receipts of many dentifrice powders and tinctures designed both to strengthen the teeth and gums and as preservatives against the diseases of these parts. Such powders and tinctures do not offer any interest to us, since they do not much differ from those recommended by other authors whom we have previously quoted. When one or more teeth, in consequence of a trauma, or from other cause, become loose and project above the level of the others, Galen removes the whole exuberant part by means of a small iron file. In performing this operation, after having covered the gums with a soft piece of cloth, he holds the tooth to be filed steady with the fingers of the left hand, using the file in such a way as not to give the tooth any shock. Besides, he does not complete the operation at one sitting, but rather interrupts it as soon as the patient feels any pain, and continues it after one or two days. In the meanwhile, he makes use of remedies suited to strengthen the loosened teeth, and bids the patient remain silent and nourish himself with liquid or soft food. When the teeth, without the action of external causes, become loosened, Galen holds that this is due to a relaxation of the dental nerve in consequence of an excessive abundance of humors. In such cases he counsels the use of desiccative remedies. Galen, like ancient authors in general, is not very favorable to the extraction of teeth with the forceps. Even he seems convinced that a tooth may be made to fall out, without pain, by means of the application of certain remedies, to which we have already alluded. However, in one of the Galenic books[183] we find the precept already given by Celsus, that before extracting a tooth the gums must be detached all around; from which one may argue that, at least in certain cases, instrumental extraction was considered inevitable. Galen even alludes to the pain which sometimes remains after the extraction of a tooth, and is of the opinion that this depends upon an inflammatory condition of the stump of the dental nerve.