94 WOODY TISSUE. 
Il.—WOODY TISSUE. 
60. This form of tissue consists of tubes of extreme tenuity, — 
and great length, varying in diameter from the 1-200th to the 
1.3000th of an inch, tapering towards each extremity, ex- 
hibiting no visible pores, and possessed of extreme tenaci 
ty. It is regarded by many as merely elongated cellular tis- 
sue, but differs in three points, the length of the tubes, thei 
extreme tenuity, and their great toughness or strength. I 
may be termed fibrous tissue, as the tubes are arranged in 
parallel lines in bundles, and readily split into smaller and 
smaller fibres. As the fibres lie in the direction of the stem, 
in cutting wood it is easy to split it longitudinally, because a 
we then simply separate adjoining fibres; but if attempting 
to divide it transversely, this is not so easily effected, as we 
must then cut them across, and rupture their substance. 
61. It is this tissue that gives strength and toughness to — 
vegetable fibre, and it is very abundant in those plants which — 
afford good material for the manufacture of ropes, linen, &c. : 
of the Plants used for this purpose, New Zealand flax 
m tenax), affords the strongest material. The 
followihg table by Labillardiere, shews the comparative 
strength of different vegetable Slocs, by the comparative 
weights which posit of each could bear without breaking. 
_ New Zealand Flax, i 
Hemp (Cannabis sativa), 
Flax (Linum usitatissimum), 
Pita Flax (Agave Americana)) : é 4a 
en ie ee SO 
2 ee 
Silk is stronger than either of these, 34. being the pro- 
_ portion of its tenacity to the above. Cotton is composed 
chiefly of cellular tissue, and is very inferior in tenacity. 
; 62. The most simple form of woody tissue is that of a 
n fibre, Warren ary hho! era de 
amples ee one " 
