In regard to the filling of decayed teeth, Giovanni of Arcoli says that, in the choice of the substances to be used, the _complexion_ (constitution) of the teeth must be taken into consideration; and according as this is cold or warm, it is necessary to perform the filling with substances which are, by their own nature, warm or cold, thus acting in opposition to the dyscrasia of the tooth: “_Eligantur calida aut frigida secundum opportunitatem, in contrarium dyscrasiæ dentis._” As to the quality of the complexion, this might be deduced, says the author, from various signs, among which the color of the gums, these being red in the warm and humid complexion, yellowish in the warm and dry, brownish in the cold and dry, and whitish in the cold and humid complexion. When, however, the complexion does not show any distinct characteristic, and varies but little from the average, Arculanus advises the teeth being filled with gold-leaf: “_Ubi non fuerit multus recessus a mediocritate, impleatur cum foliis auri._” Although Arculanus is the first writer who alludes to the filling of teeth with gold, nevertheless it is by no means admissible that he was himself the inventor of gold filling. His words do not at all sound to us as the announcement of a new discovery, as the enunciation of a new fact, in which the author himself had had, at least, a part, be it great or small. Nothing of all this; the advice as to filling the teeth, in certain cases, with gold leaf is given quite impersonally, and is found, as if it were a point of minor importance, at the end of a long paragraph, which includes various other counsels in regard to the filling of teeth, one of which is, that this operation should not be performed with too great violence.[265] In short, the writer does not show the least intention of putting in evidence the aforesaid fact, or of giving to it any special importance. We must, therefore, hold that gold filling had already been in use for a long time among dentists, and that Arculanus simply mentions what was done by the dentists of those days. (See note page 164.) It is evident, on the other hand, that he had no special competence in dental art, when we consider that he was even ignorant of the exact number of dental roots. Naturally, the question here arises: At what period did gold begin to be used for the filling of teeth? But unfortunately history has not, up to the present, furnished us any evidence which may lead to the solution of this problem. For the eradication of a tooth Arculanus gives three very precise indications: (1) When the pain resists every other means of cure. (2) When there is any danger of the disease spreading to the neighboring healthy teeth. (3) When the tooth is troublesome in speaking and in masticating. Before extraction, the patient must be prepared for it by bloodletting, purgatives, and narcotics; and the operation must be commenced by separating the gums from the tooth.