Dangers attending Tecthing.—The teeth are formed in closed sacs, and in rising to the surface in the progress of their growth they slowly penetrate the gum from below; a process familiarly called "cutting* the' teeth." The minuter physiology of this process will be described in a separate article (see TEETH); in the present it will be sufficient to indicate shortly the dangers to which children are exposed, particularly during the period of the first dentition, or from five months old to two years or more. Infants are occasionally said to die of "teething;" but this, like many other vague terms, may be said to be only a cloak for ignorance; for the mere cutting of the teeth is never, by itself, mortal, or even a serious source of suffering. It only becomes a cause of disease by its reflected influence on the delicate nervous system of the child. The period of dentition, in fact, is one during which the whole organization of the infant is under going a revolution; in passing from an exclusively milk-diet to one of a more complex character, the entire digestive system undergoes a corresponding development. The diseases of this period of life correspond in importance with the great physiological changes taking place in it, and with the dangers of derangement in the just order or symmetry of their development. If these diseases often appear to be due-directly to the
cutting of a tooth, it is because complex causes of disorder have prepared the way for a morbid change, which is ready to be developed into activity by a comparatively slight irritation. The principal diseases of dentition are diarrhea (q.v.), convulsions (q.v.), vomiting, and hydrocephalus, or tubercular inflammation of the membranes of the brain, which are all apt to originate at this period of infantile life, and to coincide more or less with the development of the first set of teeth. It is very doubtful how far the operation of cutting the gum with a lancet, so commonly supposed a specific for the diseases of dentition, ought to* encouraged. Sometimes:there is evident irritation, or even inflammation of the gum, and then the operation will probably at least do no harm; but the indiscriminating use of the gum-lancet, at the request of anxious but foolish mothers and nurses, is characteristic of a weak and erroneous routine practice, and must be denounced as an unwarrantable interference with the truly beautiful pro cess by which the tooth is gradually evolved from its socket, in most cases without any suffering. The special treatment of the diseases of dentition is discussed under the separate articles devoted to some of these diseases.