The teeth will not decay if the following things be attended to: in the first place, to avoid indigestion, and frequent repetitions of emetics. Guard against such food as is hurtful to the teeth, as dried figs, honey boiled, so as to become very hard, dates which are difficult to rub down, and all glutinous substances; likewise such things as are difficult to break, and may thereby loosen the teeth; in like manner also, such substances as set the teeth on edge, and everything which is cold and putrid. The teeth also ought to be cleaned after supper. * * * * * COMMENTARY. This Section is mostly taken from Oribasius. (Synops. v, 25.) Rhases gives similar directions. He forbids emetics, and recommends attention to keeping the teeth clean. He praises the following dentifrice: Of hartshorn, of the seeds of tamarisk, of cyperus, of spikenard, of each ℥j, of the salt of gem ʒij, to be pulverised, and the teeth rubbed with it. (Ad Mansor. iv, 21.) SECT. XXX.—FOR DULNESS OF HEARING. Dulness of hearing may be prevented by clearing away the sordes from the meatus, and by occasionally introducing into the ear a piece of linen dipped in a calefacient ointment (dropax), pressing it down, and then drawing it out; for this completely clears the opening, and at the same time, stimulates the sense of hearing. Afterwards, the meatus is to be plugged up with a piece of wool of the size of a tare for a day; and, when it is taken out, the meatus is to be anointed with the oil of almonds, of spikenard, or of chamomile, with the fat of geese, or a small quantity of ox gall. Again, after a time, rubbing mustard and figs together, introduce the collyrium thus prepared, for two hours; and then take it out and pour in oil heated in the hollow of the root of the asphodel. * * * * * COMMENTARY. This is taken from Oribasius. (Synops. v, 23.) Rhases particularly directs great care to avoid indigestion, which, without doubt, is occasionally the cause of indistinct hearing. He recommends some almond oil to be introduced into the meatus, and cautions against exposure to cold wind. (Ad Mansor. iii, 23.) SECT. XXXI.—ON DIMNESS OF SIGHT.