The day has long passed when it was disputed whether any saline bodies are promotive of the growth of plants. It is now determined that some plants will not even live without the means of procuring certain salts. Borage, the nettle, and parietaria will not exist except where nitrate of potash is in the soil; turnips, lucerne, and some other plants will not succeed where there is no sulphate of lime. These are facts that have silenced disputation. Still there are found persons who maintain that salts are not essential parts of a plant's structure; they assert that such bodies are beneficial to a plant by absorbing moisture to the vicinity of its roots, or by improving the staple of the soil, or by some other secondary mode. This, however, is refuted by the fact that salts enter as intimately into the constitution of plants as do phosphate of lime into that of bones, and carbonate of lime into that of egg-shells. They are part of their very fabric, universally present, unremovable by edul-coration however long continued, remaining after the longest washing, and always to be found in the ashes of all and of any of their parts, when subjected to incineration. Thus Saussure observes that the phosphate of lime is universally present in plants. - Sur la Veget. c.

S. s. 4.

The sap of all trees contains acetate of potash; Beet-root contains malate and oxalate of potash, ammonia and lime; Rhubarb, oxalate of potash and lime; Horse-radish, sulphur; Aspara-gus, super-malates, chlorides, acetates, and phosphates of potash and lime; Potatoes, magnesia, citrates and phosphates of potash and lime; Jerusalem Artichoke, citrate, malate, sulphate, chloride, and phosphate of potash; Garlic, sulphate of potash, magnesia, and phosphate of lime; Geraniums, tartrate of lime, phosphates of lime and magnesia; Peas, phosphate of lime; Kidney Beans, phosphate of lime and potash; Oranges, carbonate, sulphate, and muriate of potash; Apples and Pears, malate of potash; Grapes, tartrate of lime; Capsicums, citrate, muriate, and phosphate of potash; Oak, carbonate of potash; and the Lilac, nitrate of potash. Let no one fancy that the salts are a very trivial proportion of the fabric of plants. In the Capsicum, they constitute one-tenth of its fruit; of carrot juice, one-hundredth; of Rhubarb, one-eleventh; of Potatoes, one-twentieth; whilst of the seed of the Lithospermum officinale, they actually constitute more than one-half. Their constituents are as follows. -

These amounts are nearly as much of earthy saline matters as exist in human bones; but if we turn to the marrow, it only contains one-twentieth of saline matters; the blood only one-hundredth; muscle, only one-thirty-fourth; yet no one will argue that these saline constituents, though smaller than those in vegetables, are trivial and unimportant.

Saline manures are generally beneficial, and often essential. An important consideration, therefore, is contained in the answer to the query-so often put. How should saline manures be applied? Our answer is, that, when practicable, they ought to be in very small quantities and frequently, during the time of the plant's growth. No plan can be worse than soaking seed in a saline solution, for the purpose of giving such salt to the plant of which it will be the parent. It is soddening the embryo with a superfluity totally useless to it, and if it does not injure the germination, it will be most probably washed away before the roots begin to absorb such nutriment. For the mode in which salts are beneficial to plants, see Manures.