The great changes which nature is constantly bringing about around us and within us are the result of laws operating silently but unceasingly; and hence it is that in her works we see little of the failure which often disappoints human endeavours, or of the dangers which often attend on their accomplishment. Thus when her object is to render the child no longer dependent on the mother for its food, she begins to prepare for this long beforehand. The first indication of it is furnished by the greatly increased activity of the salivary glands, which during the first few months of existence have scarcely begun to perform their function, a fact which accounts for the tendency to dryness of the tongue of the young infant under the influence of very trivial ailments. About the fourth or fifth month, this condition undergoes a marked alteration; the mouth is now found continually full of saliva, and the child is constantly drivelling; but no other indication appears of the approach of the teeth to the surface, except that the ridge of the gums sometimes becomes broader than it was before. No further change may take place for many weeks; and it is generally near the end of the seventh month before the first teeth make their appearance. The middle cutting teeth of the lower jaw are in most instances the first to pierce the gum; next the middle cutting teeth of the upper jaw; then usually the side cutting teeth of the lower jaw, and lastly, the corresponding ones of the upper. This, however, is not quite invariable, for sometimes all the cutting teeth in one jaw precede in their appearance any of those in the other. The first four grinding teeth next succeed, and often without any very definite order as to whether those of the upper or of the lower jaw are first visible, though in the majority of instances the lower are the first to appear. The four eye teeth follow, and lastly, the remaining four grinding teeth, which complete the set of first, or as they are often called, milk teeth.