This natural process in a child’s development, usually commences about the third month, though it is seldom till the fifth or sixth that the teeth make their appearance through the gums. The period when the teeth may be expected is indicated by an increased irritability of the infant, the gums become tense, shiny, and swollen; while the excited glands in the neighbourhood pour out so large a quantity of saliva, that it overflows the mouth, causing the infant to _drivel_, as the nurses call this natural salivation. At the same time the child, as if to relieve the heat and irritation it feels, thrusts its hands into its mouth in the attempt to do what the watchful mother will do for it—_scratch_ the top of the gum with her nail, or, making a rasp of a rough crust, or a proper _gum-ring_, rub it freely along the top ridge, that, by abrading it of the binding cuticle, the imprisoned gum may have the power to expand. As the only benefit that can accrue from rubbing the child’s gum is the tearing or relaxing this fine but tenacious cuticle, all smooth surfaces, such as coral or ivory rings, are perfectly useless; such instruments to be of any service, should be cut into small diamonds like a fine file, and used frequently by the parent, exactly in that manner. The crust, though serviceable from its roughness, is dangerous from the chance of crumbs breaking off and getting into the infant’s throat. After the irritation and drivelling have continued for some weeks, a white line or a round spot appears on the top of the gum of the lower jaw, and ultimately of the upper; through these white spots the teeth finally burst their way in the following order: the two incisors of the lower jaw are the first to make their appearance, though frequently several weeks elapse between the advent of the first and second; the next cut are the four incisors of the upper, then the remaining two incisors of the lower jaw, one on each side, but not joining. There is now a pause for a short time in the process. The next in succession are the four eye teeth in either jaw, thus completing the infantine set of sixteen teeth. Another pause, usually of some months, succeeds before nature resumes her active operations; when she does, it is to place one double tooth on each side of both jaws, thus perfecting the child’s complement of twenty teeth. When these are shed, and nature completes her office, instead of the first ten she places sixteen teeth in each jaw, thus doubling her first complement, and making the adult set thirty-two. Each tooth as it is formed makes half a circle on its axis, and rising sideways, pierces the gum with the extreme point of its edge, revolving as it rises to the perpendicular.