We must not, however, picture to ourselves this process as going on uninterruptedly until completed--a mistake into which parents often fall, whose anxiety respecting their children is excited by observing that after several teeth have appeared in rapid succession, the process appears to come to a standstill. Nature has so ordered it that teething which begins at the seventh or eighth month, shall not be completed until the twenty-fourth or thirtieth; and has doubtless done so in some measure with the view of diminishing the risk of constitutional disturbance that might be incurred if the evolution of the teeth went on without a pause. As a rule the two lower central incisors or cutting teeth make their appearance in the course of a week; six weeks or two months often intervene before the central upper incisors pierce the gum, but they are in general quickly followed by the lateral incisors. A pause of three or four months most frequently occurs before we see the first grinding teeth, another of equal length previous to the appearance of the eye teeth, and then another still longer before the last grinding teeth are cut. Though a perfectly natural process, teething is almost always attended with some degree of suffering. This, however, is not always the case, for sometimes we discover that an infant has cut a tooth, who yet had shown no signs of discomfort, nor any indication that teething was commencing, with the exception of an increased flow of saliva. More frequently indeed, the mouth becomes hot, and the gums look tumid, tense, and shining, while the exact position of each tooth is marked, for some time before its appearance, by the prominence of the gum; or the eruption of the teeth is preceded by much redness, and great heat of the mouth with profuse flow of saliva, and even with little painful ulcers of the edge of the tongue, or of the inner surface of either lip. With either of these conditions the child is feverish, fretful, and cries from time to time with pain, while at the same time the bowels often are relaxed, or the child coughs and wheezes as if it had caught cold. Symptoms such as these make up what nurses mean when they say that the child is suffering from its teeth, and this opinion is constantly followed by a request to the doctor to lance the baby's gums. Now this little operation when really called for often gives great relief, both to the local discomfort, and also to the general ailment from which the infant suffers, but it is often done when there is no occasion for it, and when consequently it causes needless pain, and does no good. There are four different conditions in which it may be right to have the child's gums lanced: First. When a tooth is very near the surface, and by cutting through the thin gum the child may be spared some needless suffering.