262 Of the Bark of ST rees. 
wood, and partly from the drying and fhrinking up of its 
bladders, and of their component fibres; whereas the 
veffels in the bark are many of them originally formed s 
therewith; and thofe which fucceeded them are not 
caufed by any rupture as thofe in the pith are, but from 
a regular difpofition of the parenchymous fibres, and con- 
flipation of the bladders thereof; all which will appear 
very plain upon viewing the three figures 477, 478, 
and 479. 
It has been before obferved, that the lignous or towy 
parts of all plants are tubular, and that the juices are 
conveyed the whole length of the plant through an in¬ 
finite company of fmall tubes. 
Thefe very tubes or lymphaeduCts are likewife made up 
of other yet much fmaller tubes, fet round together in a 
cylindrical figure ; by which alfo appears the admirable 
fmallnefs of thefe fibres; for there are fome lymphaedudts 
that may be reckoned fifty times fmaller £ than an horfe- 
hair, and thofe minute fibres are alfo compofed of other 
fuch fibres, but much fmaller, is not altogether impro¬ 
bable ; allowing therefore but twenty of thefe to compofe 
a thread no bigger than one of thefe lymphaeduCts; then 
one of thefe fibres muft be thouland times fmaller than 
an horfe-hair. 
They may be obferved in a very white and clear piece 
of afh torn carefully lengthways, and fometimes alfo in a 
very white piece of fir. 
In the Eaft Indies they manufacture the bark of a 
certain tree into a kind of fluff or cloth; it is fpun and 
dreffed much after the manner of hemp : the long fila¬ 
ments which are feparated from it, upon beating and 
fleecing it in water, compofe a thread of a middle kind 
between 
f Grew. Ana. Plant, p. 113. I Ibid. p. 112* 
