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such considerations, it is not improbable that, on the contrary, some 

 new light may be thrown upon the functions of the animal economy 

 by investigations respecting those of vegetables, where the necessary 

 experiments may be repeated any number of times, and where the 

 influence of efficient or defective organs may be observed with the 

 most deliberate attention. 



The parts separately noticed on the present occasion, are the roots, 

 the stem, and the leaves. The roots and leaves have been compared 

 by all naturalists, both ancient and modern, to the intestines and 

 lungs of animals. The analogy also, between the sap of vegetables 

 and the blood of animals, is very obvious ; and the circulation of sap 

 in the former, as far as is necessary to, or consistent with, their state 

 of existence, is very satisfactorily established by the experiments for- 

 merly communicated to us by Mr. Knight, in addition to those made 

 by other naturalists. 



With respect to the roots, no experiments appeared wanting to 

 determine that no defect in the action of this organ occurs from age, 

 and consequently that the debility and diseases of old varieties of 

 fruit were not derived from this source. The duration of roots, in 

 old coppices, that are felled at stated periods, appeared to the author 

 sufficient to establish that the quantity of produce is not diminished 

 by age of the roots. The inability also, of a seedling stock to give 

 the character of youth to an inserted bud or graft, seemed to proyp 

 how little is effected by undoubted youth of the root. 



Mr. Knight ascertained, however, by an experiment of an opposite 

 nature, that the stock may be affected by the graft. By planting 

 cuttings of some very old varieties of apple, he obtained stocks which 

 would soon have manifested the usual appearances of age. At the 

 end of two years these were grafted, at about two inches from the 

 ground, with new and luxuriant varieties ; and at the end of five 

 years the roots were examined, and were found to contain ten times 

 as much alburnum as they would probably have contained if they 

 had not been grafted ; and they were also wholly free from disease. 



Another kind of experiment was next made upon the effect of 

 grafting young wood upon old, the old having first been grafted upon 

 a young stock, in a situation where it would not have survived the 

 second or third year. But when a portion of an old golden pippin 

 was thus included between two portions of a crab, the wood was 

 found to grow just as well, and to be just as healthy as the stock 

 and branches. 



In other experiments the author tried the effect of placing young 

 grafts upon old ones, that had long since become cankered. The old 

 ones being cut off at the distance of a foot from their original junc- 

 tion, he regrafted them with new and healthy varieties, and he found 

 that they became, in consequence, perfectly freed from every appear- 

 ance of canker. 



The author having thus ascertained that the debilities of old va- 

 rieties of fruit-trees did not originate in any defective action of the 

 2 B 



