CHAPTER X. THE TEETH.-THE VOICE. "Those pearly rows with strength and beauty dight, "Sacred interpreter of human thought, COWPER. THE care of the teeth is a duty of paramount importance. A well-proportioned and complete set of teeth is not only a great feature in our personal appearance, and essential to a distinct pronunciation, but is also necessary for the mastication of the food, upon which depends, in a great measure, its proper digestion, and, as a consequence, the due nourishment of the body.* Hard and resisting," observes Dr. Coombe, as the teeth appear, they are, nevertheless, endowed with the same vital properties as other parts, and the root of each is perforated longitudinally by a small canal, 66 * Lord Bacon has paid particular attention to the subject of the teeth, and the renewal of them. The points to be considered regarding them, he observes, are, 1. The preserving of them. 2. The keeping of them white. 3. The drawing of them with least pain. 4. The staying and easing of the toothache. The binding in of artificial teeth. 6. That great one of restoring teeth in old age. 5. CLEANLINESS OF THE TEETH. 147 through which the blood-vessels and nerve are admitted to its internal structure. From these blood-vessels the tooth derives its nourishment when growing, but afterwards they almost entirely disappear. From its nerve the tooth derives that sensibility which makes us instantly aware of the contact of bodies either too hot or too cold." To prevent the teeth from being worn down by friction their visible part, or crown, is covered with a very hard, white, ivory-looking substance, called enamel, into which neither blood-vessels nor nerves have been observed to penetrate. An obvious advantage attending the vitality of the teeth is, that it enables them to accommodate themselves to the growth of the jaw and the general system at the different periods of life. The teeth being living parts, and at the same time endowed with a mechanical function, are liable to injury in both capacities. Being composed chiefly of earthy matter, such as phosphate and carbonate of lime, the contact of strong acids decomposes or destroys their substance, and leads to decay. A want of cleanliness and care in the treatment of our teeth occasions an accumulation of tartar. No time should be lost in having this removed by a dentist. A more serious evil is decay, which invariably commences at those points where foreign bodies, whether the secretions of the mouth or food, are apt to accumulate ; namely, between the teeth, or in the deep depressions in the grinding surface of the molars, which are prone to become impacted with food, and very difficult to free from it. The process seems to be that the food, or other foreign matter deposited, undergoes a fermentation, and softens the enamel. The softened portion is soon removed, and another surface undergoes a like change, until the substance of the tooth is laid bare, when the process becomes more rapid, both from the material being more readily acted upon, and a larger quantity of the agent being at work. Another obvious effect of a want of cleanliness of the teeth is the foulness of breath caused by the putridity of morsels of food collecting between them, enough of itself, surely, to induce care on this point; but should it not be, the fact may be stated, that if we do not clean our teeth ourselves, scavengers are provided to remedy, as far as possible, the evil effects of our carelessness. These are animalcules, which exist in great numbers about the roots of foul teeth, the number being in direct ratio with the untidiness of the person's mouth. The only way to get rid of these is to preserve, in every possible way, the cleanliness of the teeth. In sleeping care should be taken to keep the mouth closed, for, besides other inconveniences attending a contrary practice, the teeth are apt to be injured by the air continually passing through them. The chief cause of a caries in the teeth is, undoubtedly, external, but it may be sometimes produced by an internal cause. While, on the one hand, exposure to currents of cold air are stated to act injuriously upon the teeth, the medical practitioners of Germany and the north appeal to the opposite extreme, of the habitual use of hot aliments, as a still more general and mischievous source of the same evil. According to a Swedish writer "man is the only animal accustomed to hot foods, and almost the only animal affected with carious teeth." The same author condemns, in an especial manner, the custom of drinking hot tea and coffee. There can be no question that the extremes of heat and cold must be greatly, perhaps equally, injurious to the health. To the abuse of hot beverages as a cause of caries M. de la Salle adds the abuse or the excessive employment of sugar, and imagines that these are the two principal means by which teeth are rendered black in their enamel, and carious in their substance. If sugar act at all it must be by means of the principle of acidity which is contained in it, and consequently in proportion to the degree of affinity which this prin ciple bears to the earthy matter or calcareous basis of the teeth and their enamel, beyond that of the acids which enter into their natural composition. And the same may be observed in respect to any other acid whatever. Injurious effects on the teeth arise also from intemperate habits, unwholesome aliments, grinding very hard substances, breathing an impure and confined air, the imprudent use of mercury and strong purgative medicines, smoking cigars or pipes, improper toothpowders, &c. Fermented liquors are injurious to the teeth in proportion to the quantity and quality of the liquor which is used. Persons who are in the daily practice of drinking a quantity of wine are rendered more subject to the accumulation of tartar on the teeth. When people have habituated themselves to the use of spirituous liquors the injurious effects upon the teeth are very apparent. The teeth acquire a very stained and foul appearance; the gums, being more or less inflamed, are covered with a slimy mucus, and are often liable to bleed; the breath, also, becomes very offensive; and, as the regular passing of the spirituous liquors over the tender skin of the mouth creates a constant degree of inflammation, the heat of the mouth is greatly increased. This state of the mouth is also kept up by the increased heat of the stomach, and when, by the debilitating effects of the spirits upon that organ, indigestion is produced, the teeth very rapidly fall into a state of decay; they are acted upon constantly in the same manner as in the course of a fever, when the heat of the constitution is greatly increased. Toothache, on which we are now about to remark, becomes chronic by the dissipation and reckless carelessness of the persons we have described. The poet's remark "There was never yet philosopher That could endure the toothache patiently," is most truthful; yet the complaint being so common is, perhaps, the reason why so few sympathise with the patient. The origin of this pain, besides being influenced by the causes we have mentioned, may be various; it may arise from decay, when, of course, the dentist only can afford permanent relief. Indeed, this science has been so successfully pursued of late by many eminent practitioners, that the sufferer from toothache may readily find the means of assuaging pain. One of the best local applications for toothache is warm salt and water. It should be made as strong as possible, a little taken into the mouth, and held for some minutes on and around the painful tooth, when it may be rejected, and a little more taken into the mouth two or three of such applications generally succeed in affording relief. The mastication of pungent, aromatic, and stimulating plants will sometimes succeed in relieving the pain, such as ginger, horseradish, common hartwort, or pellitory root. It is necessary, however, that during the treatment due care and caution should be observed. The strictest attention ought to be paid to diet and regimen. Night air, exposure to dews, or to easterly winds, ought to be avoided; and, when the attack is removed, cold water poured over the head will sometimes prevent a recurrence. Toothache is frequently occasioned by the absurd attempts made to improve their complexion by the votaries of fashion. The paints and lotions employed for this purpose often contain preparations of lead, mercury, zinc, or bismuth, the pernicious effects of which frequently manifest themselves in the production of severe pains in the jaws and teeth, or in the complete destruction of the latter. When the digestion is healthy and vigorous toothache is rarely experienced, except it be in consequence of a chill; but even then severe and continued pain is seldom felt if the stomach has been previously healthy. Tooth-brushes ought to be of a medium stiffness, |