J. D. L., of Aiken, S. C, asks of pomologists to give some information relative to the blue rot in plums, which worries his fruit more than the curculio. He also wants to know if any reason can be assigned why some plum-trees, probably the General Hand, which are eleven years planted, strong and thrifty, seldom bear, while other varieties have plentiful crops.

(Asa Thomas.) The Manchlneel tree (Hypomane mancinella) attains a large size on the sea-coasts of the West Indies and our own continent, being common at Key West, where it is found of the height of thirty or forty feet. It has the aspect of the pear-tree at a distance, while the fruit resembles, in appearance and scent, a small apple, which has deceived your correspondent. The abundance of the fruit is so great, that the ground appears to be paved with them. They possess very little pulp, the interior being occupied by a deeply grooved nut as large as a chestnut. No animals, except goats, and, of birds, the maccaw, choose to feed on them, and they become brown, dry, and spongy, and as useless as they are deleterious. The juice of the tree is poisonous. Catesby was blind for some days in consequence of getting it in his eyes. It is said sleeping under the tree is fatal; oily sub-■tanoes are the best remedy for this poison. The poisonous Upas approaches nearer to the anomalous manchlneel than to any plant of the Autoearpee. The seeds, formerly so much employed for buttons in England, are the produce of the soapberry-tree, sapindus Saponaria, of the West Indies, which produces soap, as does an exclusively American tree, S. marga--natus, which is found on the coast of Georgia and Florida, and, in the interior, as far as Arkansas. The berries are about the size of a cherry.

The soap is found in the fleshy pulp of the berries, and also in the root, but, if it is used too frequently, and of too great strength, it is apt to burn and injure the texture of the cloth.