According to Mr J. C. Clifford, who lately delivered a lecture before the Balloon Society of London, the art of dentistry in America is far in advance of the practice of the Old World. The dentists there are specialists. One will devote himself to extracting teeth, another to filing them, another to making artificial teeth, and so on. The lecturer also stated that these clever dentists had found out that if necessary, they could take a tooth out, cut off the diseased end, replace it, and it would grow firm again in a few days. Transplanting was also successfully carried on. An interesting discussion has lately arisen concerning the deterioration of pictures by exposure to light and from other causes. There seems to be no doubt that in the case of water-colour pictures this deterioration is an undeniable fact. In oil-colours, the pigments being used in greater masses, and each particle of colour being inwrapped as it were in a protecting globule of oil, there is no perceptible change except a gradual darkening, due most probably to the oil and varnish. The number of organic substances upon which light will exert a bleaching action is far greater than is commonly supposed, and pigments of organic origin should always be regarded with suspicion. Luckily for our artists, there are pigments at their disposal which are permanent in character, and these alone should be used if they wish their works to remain ‘a joy for ever’ as well as ‘things of beauty.’ It seems a great pity that the art of producing pictures in far more permanent pigments, that of drawing in pastels or coloured chalks, should have been almost lost sight of, or at least relegated to the itinerant artist who decorates our pavements with impossible landscapes. In the middle of the last century, this art flourished in France; and works by its votaries, as fresh now as the day they were executed, are much sought after. In France, a Society has been formed for the revival of pastel-work, and its influence has been felt in London, where an excellent Exhibition of Coloured Chalk Drawings has lately been opened. We may hope that these efforts will lead to a revival of a lost art, which has other advantages besides permanence to recommend it. In framing a picture covered with glass, be it a water-colour, a photograph, or an engraving, there is one precaution which should always be adopted, but is too often neglected—the glass should fit the frame exactly, and should be cemented to the wood inside by a slip of thick paper. This should be glued all round the frame; and if done properly, will exclude all dust, dirt, and undesirable vapours. The backboards, too, should be well papered, so that the picture may rest in a dust-proof and air-tight receptacle.