These rules are: (1) It is necessary to guard against the corruption of food and drink within the stomach; therefore, easily corruptible food--milk, salt fish, etc.--must not be partaken of, and after meals all excessive movement, running exercises, bathing, coitus, and other causes that impair the digestion, must also be avoided. (2) Everything must be avoided that may provoke vomiting. (3) Sweet and viscous food--such as dried figs, preserves made with honey, etc.--must not be partaken of. (4) Hard things must not be broken with the teeth. (5) All food, drink, and other substances that set the teeth on edge must be avoided, and especially the rapid succession of hot and cold, and _vice versa_. (7) Leeks must not be eaten, as such a food, by its own nature, is injurious to the teeth. (8) The teeth must be cleaned at once after every meal from the particles of food left in them; and for this purpose thin pieces of wood should be used, somewhat broad at the ends, but not sharp-pointed or edged; and preference should be given to small cypress-twigs, or the wood of aloes, or pine, rosemary, or juniper, and similar sorts of wood, which are rather bitter and styptic; care must, however, be taken not to search too long in the dental interstices, and not to injure the gums or shake the teeth. (9) After this it is necessary to rinse the mouth, using by preference a vinous decoction of sage, or one of cinnamon, mastich, gallia, moschata, cubeb, juniper seeds, root of cyperus, and rosemary leaves. (10) The teeth must be rubbed with suitable dentifrices before going to bed, or else in the morning before breakfast. Although Avicenna recommended various oils for this purpose, Giovanni of Arcoli appears very hostile to oleaginous frictions, because he considers them very injurious to the stomach. He observes, besides, that whilst moderate frictions of brief duration are helpful to the teeth, strengthen the gums, prevent the formation of tartar, and sweeten the breath, too rough or too prolonged rubbing is, on the contrary, harmful to the teeth, and makes them liable to many diseases. Shortly after Arculanus, when the Middle Ages are over--if they end with the middle of the fifteenth century, though perhaps not if the later date of the discovery of America is to be taken as the medieval terminal--John de Vigo has in a few lines a very complete description of the method of filling teeth with gold-leaf which deserves to be quoted. Only that it was a common practice he would surely have described it more in detail, though he could have added nothing to the significance of what he has to say: "By means of a drill or file the putrefied or corroded part of the teeth should be completely removed. The cavity left should then be filled with gold-leaf."