ON THE DIPFERENT SORTS OF WOOD. 163 



SO very plain, so easily seen, that, strip off the bark, atid a 

 child would acknowledge and understand it ; as the buds 

 appear coming out from the interior of the wood in every 

 part. But how many truths does this substantiate ! It 

 proves which is the vital part of a plant : that the impreg- Consequences 

 nating Ijne, which runs into the seed, is hkevyise tound this, 

 running next the pith in the stem ; that this is t^e line of 

 life, from which also all buds proceed ; that the seed and 

 bud are the same thing, at least differing in trifles only ; 

 and that they both owe their existence to this same vital 

 part, one shooting in the flower, the other in the stem of a 

 plant. In herbaceous plants this same line runs within the 

 pith, but equally gives life to bud and seed ; hence the 

 truth of Linnajus's observation, when he gave siuch conse- 

 quence to the pith of some plants. 



There is something so curious in the manner in which the ^^nner m 

 , , . ^ • 1 • . , . , . , . , which thebud 



bud IS tirst united with the sap vessel that nourishes it, that, is first vmited 



as I have not exactly shown the process, I shall give it here. "^'^^^ }^^, *^P- 

 , , J -1 J I • 1 • 1 I ■• f. fp /> vessel that 



1 have described the manner in which the line ot lite first nourishes it. 



generates the bud by forming a knot on that line, and 

 breaking the outward ends. Each end then becomes a 

 bud, and it is the busiiiess of the wood to form a covered 

 way for the passage of the bud to the exterior, which it 

 does by bending some and raising other parts of its vessels, 

 in the middle of which the bud passes to its cradle ; but no 

 sooner does the knot form on the line, than it becomes a 

 signal for the root to send up a vessel for the nourishment of 

 the new bud, and by the time it reaches its cradle, this ves- 

 sel (loaded with sap) arrives at the same place, and fastens 

 itself to the bud, aflbrding it that nourishment the milky 

 juice of the albumen could no longer give it. It i,s exactly 

 the same process as that in the seed, where the milky albu- 

 men first supports, and is then succeeded by the nourishing 

 vessels. 



I shall now give a curious proof, that the wood is the only 1'he wood th* 

 part which carries the sap for the nourishment of the plant ; conveys, th« * 

 and that the plant dies, if the wood vessel is lost. In «ap foi nou» 

 tracing the various diseases of plants, especially in our kit- plant. 

 chen vegetables, it occurred to me to examine thoroughly 

 that which is called smut iu potatoes; and compare it with Diteasej«f 

 M2 tb^P'*""- 



