82 
HISTOLOGY OF VEGETABLES. 
known as Grass-cloth. The fibres of the Phormium 
tenax , or New Zealand Flax, are much stronger than 
those of the common Flax, but are much more easily 
broken, in consequence of the outer membrane being 
excessively brittle. Although these fibres will resist a 
very considerable force applied to them longitudinally, 
if tied into a knot so that the fibre is twisted, or if the 
force be applied transversely, they readily break. 
Of all the woody fibres I have examined, those 
obtained from the leaves of the Pine-apple plant appear 
to be the finest. For the sake of comparison, repre- 
sentations are given of the fibre of Flax (Fig. 68, a), 
of China-grass (Fig. 68, c), and of the Pine-apple 
(Fig. 68, b), as seen under a power of four hundred 
diameters, by which it is well shown that the last is 
much smaller than either of the others. 
It is important, under certain circumstances, to 
determine the true nature and composition of some of 
the textures used as articles of clothing, &c., and this is 
readily done if we bear in mind the characters of the 
elementary tissues. In linen we find the component 
threads merely longitudinal, rounded, unmarked fibres, 
such as have been already figured in Flax, Fig. 69 ; but 
where cotton has been employed solely, or by admixture, 
its fibres, as shown in Fig. 70, are recognised as 
flattened and more or less twisted bands, bearing other 
marks of resemblance to hairs, which, in fact, they are, 
since in the condition of elongated cells, they line the 
inner surface of the pods. Fig. 70, represents the isolated 
