Anaiomkal Descrtplion of the Fir Tree. 257 



ever another, from the extremities of the filaments of the roots 

 to those of the branches. 



The radiates lie along that part which looks as if it were woven ; 

 and in many cases they have the appearance of vessels of consi- 

 derable dimensions : but this is only to be seen when they are 

 filled with coloured matter, which is evidently turpentine. Where 

 this is not visible, there is generally something like a very fine 

 dew in miniature on the reticular part, standing in rows both 

 longitudinally and horizontally. The radiates apparently per- 

 form the same office as in the oak and other trees. The sort of 

 network likewise lies in the horizontal direction, and breaks the 

 rectilineal perpendicular pressure of the juices contained in the 

 longitudinal vessels ; if such they be. At all events it prevents 

 the juice of the tree from descending in a right line, whether 

 contained in vessels or in the longitudinal cavities between the 

 portions of fibrous matter not connected in a tubular form, yet 

 sufficiently close together to support moisture on the same prin- 

 ciple as that of capillary attraction in tubes. This principle of 

 attraction, indeed, is not limited to vessels of any particular 

 form, or to solids forming any vessels at all ; for two plane sur- 

 faces of glass, or any other matter, being moistened, and placed 

 sufficiently near to each other, without touching, will occasion 

 water to ascend between them, as it would in a tubular vessel. 



If these woven flax-like fibres be hollow tubes, it is probable^ 

 that they principally contain the more watery matter absorbed 

 by the plant, before chemical union takes place ; and they may 

 be presumed to be formed of a film, similar to that which soon 

 appears on the surface of water when poured on tar. Though 

 after the texture of the wood is formed, and the chemical union 

 of the different elements of the tree has taken place, it might 

 be supposed, that the contents of the vessels would be coloured 

 matter ; yet they are (juite transparent and colourless. Still it 

 is difficult to say, whether the little globules, like dew in minia- 

 ture, which appear in beautiful rows, are contained in longitudinal 

 vessels, or move along by attachment to the filmy-formed thread, 

 now become woody fibre, in a manner similar to the perspiration 

 on the hairs of animals. 



The glol)ules which are considerably tinged with colour, and 

 are, no doubt, the blood of the plant, are pressed along the 

 woody fibres, as from one piece of network or lodgement to an- 

 other. The other sort of loui^itndinal vessels, if such they may 

 be called, are very irregular 5 and appear like a number of the 

 small ones ruptured, and combined into one, being evidently open 

 all round like a net purse. They generally contain considerable 

 tjUHUtities of fluid ; which is supported by thin and seemingly 



Vol. 51. No.240. Jljril 181S. R tough 



