Page:Proceedings of the Royal Society of London Vol 1.djvu/220

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Mr. Knight begins his paper by stating, that every tree, in the usual course of its growth, generates the buds that expand in the succeeding spring; but if these buds are destroyed. during the winter or early part of the spring, other buds are in many species gene- rated; which buds perform the oﬂice of those that previously existed, except that they never afford blossoms or fruit. This reproduction of buds has not escapcd the notice of naturalists; but it does not appear that they have ascertained from which of the various sub- stances of the tree the reproduced buds derived their origin.

After noticing some erroneous opinions respecting the origin of buds, Mr. Knight proceeds to relate some observations and experi— ments made by him on this subject. If the fruit-stalks of the Sea Cale (Crumbs maritime) are cut off in the spring, the medullary sub- stance decays, and a cup is formed, the sides of which consist of a woody substance, perfectly similar to the albumnm of trees. From the interior part of this substance, new buds are frequently gene- rated in the ensuing spring: hence it is obvious, that the buds. in this case, do not spring from the bath; but it is not equally evident that they do not spring from some remains of the medulla.

In the autumn of 1802, Mr. Knight discovered that the potatoe possessed a similar power of reproducing its buds; which buds sprung from tubers generated on the surfaces made by the knife in dividing the root. In a former paper he has given some reasons for Supposing that the internal substance of the potatoe is alburnous : he now observes, that there is in the young tuber a transparent line through the centre, which is probably its medulla; and that the re- produced buds did not spring from the central part, nor from the surface in contact with the bark, but from what he has supposed to be the albumum of the root.

The author now gives an account of the experiments made, in the autumn of 1802, on young apple, pear, and plum trees, raised by him from seed, and, at that time, about two inches above the ground. These plants, after removing some of the soil, Were cut oil”, about an inch below where the seed-leaves formerly grew; so that a portion of the root, about an inch long, and without any bud upon it, re- mained exposed. In the beginning of April, many small elevated points were seen on the bark; these appeared to proceed from the albumum, and, as the spring advanced, perforated the bark, and produced shoots.

As it might be supposed that in the preceding experiments the buds may have originated from the medulla, Mr. Knight thought it right to make some similar experiments on old trees ; and found the buds were reproduced by such trees, exactly in the same manner as by the annnal roots.

Mr. Knight, in a former paper, has remarked, that the central