Page:Popular Science Monthly Volume 3.djvu/262

250 trees, which became so painfully apparent during the previous spring, to the action of drought and cold. The year preceding was, in New England, one of the dryest on record, the ground, when winter set in, holding a comparatively small amount of moisture. This left the roots of trees deficient in sap. Not being well protected by snow, the ground in winter was frozen to a great depth, and, as the frost left the roots in spring, they remained for some time in contact with relatively dry earth, thus causing a shock too great for their vitality to withstand. During the succeeding summer Prof. Shaler also observed a remarkable scarcity of snakes and toads, which he is likewise inclined to ascribe to the great severity of the previous winter. Concerning the effect of such climatic accidents on the character of our forests, he says:

"Small as the destruction of forest-trees is, it will doubtless add several per cent, to the deciduous trees of New England, and remove an equal amount of conifers. The conifers seem to be relics of an old time, and not competent to wage a successful war with their younger and more elastic competitors, the oaks, beeches, and other deciduous trees. Every gap that is made in our forests of cone-bearing species is filled not with their legitimate successors, but by forms from the other class of trees. Let us suppose that the shock of the last season had been great enough to kill off the whole of our pines, the result would have been a complete change in the character of our forests; oaks generally would take the vacant place. This would affect the character of the undergrowth very materially, for the lesser plants of a pine-wood are very different from those which flourish beneath oaks. This would have had a very great effect upon insect-life, and more or less directly influenced the number and character of the birds and the mammals. Even the climate would be in some small measure influenced, for a pine-forest retains the snow better than one which loses its leaves in the winter, and thus tends to secure a more equable temperature in the region where it lies. Thus we see that an accidental drought might bring about a change in the assemblage of vital conditions on the surface of the land, as great as those which, when recorded in strata, we accept as indicating distinct geological formations."

Dental Art among the Japanese.—Dr. W. St. George Elliott, formerly of this city, now at Yokohama, Japan, sends to the Dental Cosmos an interesting account of Japanese habits in regard to teeth, and of the state of dentistry in that empire. He says that the teeth of the daughters of Japan are objects of envy, and it is remarkable that a nation who place so much value upon their teeth should keep up the custom of blacking them after marriage. As a race the Japanese have not good teeth, and it is rare to find an old person with any at all. Their tooth-brushes consist of tough wood, pounded at one end to loosen the fibres. They resemble paint-brushes, and owing to their shape it is impossible to get one behind the teeth. As might be expected, there is an accumulation of tartar which frequently draws the teeth of old people. The greatest accumulation is behind the lower orals, and these are frequently cemented together by a dense, dark-brown deposit, a quarter of an inch in thickness. Their process of manufacturing false teeth is very crude. The plates are made of wood, and the teeth consist of tacks driven up from the under side. A piece of wax is heated, and pressed into the shape of the roof of the mouth. It is then taken out and hardened by putting it into cold water. Another piece of heated wax is applied to the impression, and, after being pressed into shape, is hardened. A piece of wood is then roughly cut into the desired form, and the model, having been smeared with red paint, is applied to it. Where they touch each other a mark is left by the paint. This is cut away until they touch evenly all over. Shark's-teeth, bits of ivory, or stone, for teeth, are set into the wood and retained in position by being strung on a thread which is secured at each end by a peg driven into the hole where the thread makes its exit from the base. Iron or copper tacks are driven into the ridge to serve for masticating purposes, the unequal wear of the wood and metal keeping up the desired roughness. Their full sets answer admirably for the mastication of food, but, as they do not improve the looks, they are worn