When a puppy is about three and a half to four months old, the upper incisor nippers are loose, and sometimes have fallen out, and the permanent ones are just coming through the gums at this part. At the same time, the fourth upper molar, which is the fourth from the tusk, makes its appearance. (It will be noticed that though the lower temporary molars are cut before the upper ones, the reverse is the case with the permanent teeth.) In the course of another few days, or a week, the other upper deciduous incisors are shed, and the permanent ones appearing in their place, then the lower milk incisors commence to fall out, and the new ones to make their appearance. About the same time the tusks are showing themselves through the gums. In some cases, the tusks do not appear until all the other teeth are up. This is about the general order in which the teeth are cut, but of course there are exceptions, and in some instances, the permanent tusks appear just after the eruption of the upper centre incisors. It does not always happen that the temporary teeth are shed before the permanent ones appear, and the latter shoot up either beside, in front, or behind the milk teeth. Then the latter teeth should always be drawn, or the permanent ones may not come straight and regular. With regard to the permanent molars, the first to appear, as previously stated, is the fourth one. It makes its appearance just behind the last temporary molar. Before it is fully up, the fifth upper molar has passed through the gum. At about this same time the fifth, or large permanent lower molar, is appearing; this is quickly followed by the sixth, and again by the seventh. About the same time as these two latter teeth are erupting, the temporary molars in the same jaw are falling out, and their places are being filled by permanent ones. About a week later, the first lower milk molar is shed and the permanent one cut; this is followed by the second and third ones. The corresponding teeth on each side of the jaw, as, for instance, the fourth molar on the left and right sides, are erupted simultaneously. By the time puppies, such as St. Bernards, mastiffs, retrievers, and others of similar size, are about four months old, the process of dentition is complete. Fox-terriers, and other dogs of this size, are in some cases a fortnight later, and small toy dogs are often from six to eight months of age, or even later, before the mouth is fully furnished. It is impossible to tell the age of a dog with any certainty after dentition is finished, but up to then one can judge the age to within a fortnight, if it is borne in mind how the teeth are erupted. After this time, and up to a year or eighteen months, if, together with the condition of the incisor teeth, whose middle prominences at this time show signs of wear, one takes into consideration the general appearances of a dog, a fair judgment as to age may be formed.