THE FIBRES, &C. 57 



the fibrous bundles which are really joined or continuous 

 with the cellular tissue. If the operation be continued, 

 the water affects a part of the elongated cellular tissue 

 interposed between the fibres, and each fibre is divided 

 into several fibrillas : if the maceration be still pursued, 

 the vessels themselves are disunited, and only a homoge- 

 neous paste is obtained, such as is seen in the manufac- 

 ture of paper. The analysis of this popular operation 

 shows how the anatomists of old were deceived when 

 they thought that maceration was a good means of 

 knowing the intimate structure of vegetables ; it is, on 

 the contrary, a proceeding eminently defective, since it 

 only acts by destroying the more delicate parts. 



The way in which I have represented the structure 

 of fibres, explains very well why they are, even without 

 maceration, more difficult to break transversely than to 

 split longitudinally, or to separate from the neighbour- 

 ing cellular tissue. In breaking a fibre transversely, it 

 must destroy the walls of a number of cellules ; whilst, in 

 a longitudinal direction, we only meet with now and 

 then the partitions which terminate the tubular cellules. 

 This is the reason why all the fibrous parts of plants are 

 more easily split longitudinally than transversely; this 

 is what workmen call, to follow the grain. Parenchy- 

 matous parts, on the contrary, may be broken indiffe- 

 rently in all directions, because they are composed of 

 regular cellular tissue. 



The different tenacity of the fibres of plants, results 

 — 1st, from the nature itself of the membranous tissue; 

 2dly, from the number and compactness of the mole- 

 cules which are there deposited ; 3dly, from the number 

 of the vessels and tubular cellules of which each bundle 

 is composed; 4thly, from the degree of elongation of 

 the tubular cellules. The most tenacious fibres which 

 are known, are those of the Phormium ienax, called, very 



