204 



FARMERS' REGISTER. 



[No. 4 



wood is formed, is elaborated in the upper part of 

 the plant, and sent downward ; and not in the 

 root, and sent upward. This has been establish- 

 ed by such experiments as the following : "Early 

 in the spring, a tight ligature was lied around a 

 young branch ; and in this condition the branch 

 was sufi'ered to remain for the season. On ex- 

 amming it towards autumn, the part above the 

 ligature, was found to have increased in size, 

 whilst that below had remained unaltered. A 

 ring of bark was removed from a growing stem of 

 a young tree. When the wound commenced 

 healing, the new woody matter was formed on the 

 upper lip o(" the wound, and not on the lower." 

 Second, the new wood is produced, either from 

 the bark, or between the bark and the wood of the 

 last year, and not by that vvoud. This was proved 

 by Da Hamel in the following manner: Having 

 carefully introduced plates of lin-lbil, between the 

 bark and wood of a growing tree, he suffered it to 

 remain undisturbed ibr several years. On cutting 

 across the stem, at the end of this lime, he found 

 that the nev/ layers of wood had been deposited 

 on the outside of the tin-lbil, without in the least 

 disturbing it. Third, the origin of the wood is in 

 some way intimately connected with the action of 

 the leaves. It has long been known that the di- 

 ameter of a stem depends very much upon the 

 number of leaves which it bears ; that the larger 

 the number of leaves developed upon a stem, the 

 greater will be its diameter, and the more rapid its 

 growth. And also, that the largest quantity of 

 wood is always Ibund on that side of a stem 

 which developes most leaves. But had we only 

 these facts, on which to base a judgment, we 

 might hesitate which to consider the cause, and 

 which the eil'eci; whether to believe that the luxu- 

 riance of the stem arose from the increased nuni- 

 tier of leaves, or the increased number of leaves 

 from the luxuriance of the stem. This (jues- 

 tion, however, has been determined by direct ex- 

 periment. Mr. Knight stripped otF the leaves 

 irom the upper portion of a young shoot; as 

 the consequence, the shoot died as I'ar down as the 

 leaves were removed, whilst below that point, it 

 flourished. He alterwards, insulated a single leaf, 

 by removing a rin<r of bark, at some distance 

 above the point at which it was inserted into the 

 stem, and another at an equal distance below that 

 poin'. In the course of the summer a perceptible 

 increase in the wood took place above the lealj 

 but none below it. In another instance, he re- 

 moved a narrow ring of bark from the lower part 

 of a growing stem ; the stem afterwards increased 

 sensibly in diameter down to this ring, but not at 

 all between the ring and the leaf next below it. 

 From tliese and siniihr facts, he has inlerred, that 

 "the matter of which the wood is formed, is elab- 

 orated in the leaves and sent downwards." Fourth, 

 the portion of wood (i)rmed each year, is entirely in- 

 dependent of, and distinct from, that of every other 

 year; and when once formed, undergoes no chanf^e, 

 except the slight change which takes place when 

 jt is converted from sap-wood into heart-wood. 

 In confirmation ol' this, many curious liicts may 

 be mentioned. On what are called "line-trees," 

 in the west, certain marks are made when the 

 land is first divided ofi into lots. This is done 

 by striking with an axe, so as to cut through the 

 bark and two of three of the outer layers of the 

 yyopd. If one of these trees be examined, say 



twenty years after the marks were made, no 

 traces of them will be discovered on the outside 

 of the bark ; nor, if we cut into the wood, will 

 we find any in the 19 outer layers ; whilst we will 

 find all the marks perlijct in the 20th layer, the lay- 

 er in which they were originally made ; thus es- 

 tablishing the lact that, that layer has remained 

 unaltered since its first Ibrmation, and that all the 

 outer layers have been formed entirely indepen- 

 dent of it. Good, in his 'Book of Nature,' slatea 

 that in England, "dates of very remote national 

 eras, and the initials of monarchs who flourished 

 in caHy times, have been found stamped in the 

 very heart of the timber." M. Klein states that 

 in the year 1727, a long series of letters were dis- 

 covered in the trunk of a full grown beech, near 

 Dantzic. The letters were conspicuous in a lay- 

 er about half way between the axis and the bark 

 of the stem, whilst no traces of them could be 

 discovered, either in the layers within, or in those 

 without it. The same author mentions several 

 other facts of the same kind. "In one instance, 

 the image of a thief hanging from a gibbet, was 

 discovered, in the timber of a beech tree, appa- 

 rently drawn by nature's own pencil. In another 

 tree, the figure of a crucified man, was (bund in 

 similar circumstances ; and in another, a chalice, 

 with a sword perpendicularly erect, sustaining a 

 crown on its point. Such marks were formerly 

 attributed to miraculous intervention, or regarded 

 as marvellous sports of nature ; and on this ac- 

 count, were preserved with peculiar care." Wfien 

 rightly understood, they place the truth of the 

 above statement beyond a doubt. 



Bearing these facts in mind, we will now at- 

 tempt to decide between the two theories respect- 

 ing the formation of wood, which, at the present 

 day, divide botanists. Only two theories are men- 

 tioned ; for although, in time past, many theories 

 have been advanced, there are now but two which 

 are considered at all probable. One of these theo- 

 ries is, that the wood is produced fi-om organiza- 

 ble matter, elaborated in the leaves, and from 

 them sent down, through the liber and alburnum, 

 and thence deposited between the two in ihelbrm 

 of new wood and bark. The other theory is, that 

 the wood is nothing more than the roots of the 

 leaves, growing downward li'om their bases, just 

 as true roots grow Irom the hase of the stem. 

 The first of these theories is adopted by Mirbel, 

 and De Candolle ; the second was first advanced 

 by Da Petit Thouars, and has lately been very ably 

 defended by Prof Lindley. 



One of the arguments urged by the advocates 

 of the first theory, is this : "If a ring of bark is 

 removed from a maple tree, whose wood is white, 

 and its place carefully supplied by a ring of bark 

 from a maple, whose wood is red, the bark will 

 adhere to the old wood, uniting organically with 

 it, so that externally, the wound will be scarcely 

 seen. If the tree thus treated, be allowed to grow 

 for a year or two, a quantity of wood generated 

 in the leaves, will be Ibund beneath the ring of the 

 red wood maple bark. If it be but the roots of 

 the buds and leaves furnishing white wood, i* 

 should be white also. But it will be found that 

 red wood will be formed beneath the red wood 

 bark; therefore this wood is lormed immediately 

 by ihe bark, from materials sent down by the_ 

 leaves." To this, Lindle}' replies, "the color of 

 young wood depends entirely, and of old wood io 



