The _diseases_ that teething gives rise to in infants are very numerous, and the consequences of so natural a process are some of the most remarkable facts connected with the development of the human economy. The disorders excited by difficult dentition are, diarrhœa, convulsions, mesenteric disease, water on the brain, rickets, and remittent fever—all of them to the infant fearfully mortal diseases. Each of these affections, though so different in its locality, and so opposite in its symptoms, is induced by the same cause—long-continued irritation in the gums reacting on the delicate organization of the brain and nervous system. And, as this irritation is caused by the difficulty the imprisoned tooth finds in escaping from the fibrous membrane in which it is enveloped, and making its way through the tightly bound gum, it becomes the duty of the medical man or parent, as soon as the first constitutional disturbance manifests itself, to assist the efforts of nature to effect the escape of the tooth, by dividing the gum and leaving an aperture through which the new-formed tooth may reach its destination. But, as _lancing_ the gums, as the process is called, will be worse than useless unless _effectually done_, the gums should never be cut unless the tooth can be plainly felt below, and, to be of service, the incision must be carried down to the tooth, or else the unyielding membrane in which it is encased will be undivided, and the child put to the inconvenience of lancing without effecting the slightest benefit. As, however, the irritation commences from the first entrance of the tooth into the gum on emerging from its bony socket, and long before the actual pressure of the tooth can cause the graver mischief, or simply from the increased amount of blood circulating in the parts, it is evident that lancing the gums in so early a stage of formation is not only impolitic, but hurtful. Another mode of relief, both for the diarrhœa and convulsions that so frequently occur in weakly infants at this period, must be looked for; and that means, in all stages of dentition, from the first to the last, will be found either a source of instant relief or of certain recovery; that remedy is the _hot bath_, which, in all cases of infantine suffering, is the mother’s best hope, and should be her unshaken reliance. The time a child should be kept in a hot bath should seldom exceed _two minutes_; and, as the object is to unload some congested organ, or to relieve certain parts of their excess of blood by causing a rapid determination to the skin, the water should be hot enough to produce this effect as instantaneously as possible. When diarrhœa continues in despite of the hot bath, a little magnesia or a few grains of prepared chalk may be given two or three times a day until the excessive action is checked; or if unabated by these means, a few drops of tincture of kino is to be administered, as prescribed for diarrhœa. SCARLET FEVER, OR SCARLATINA.