Of the Trunks of Trees. 253 
As the pores or veftels are greater or lefs, fo are aifo 
the infertions, to the naked eye, the largeft only are dif- 
cernable j but by the help of the microfcope they appear 
very numerous. 
The infertions in the trunk are vifible in a tranfverfe 
fection, and are difpofed in even lines or rows throughout 
its whole breadth ; they are reprefented as they appear in 
the root of a vine, when viewed through a microfcope, 
by E F, fig. 471. 
The pores of the pith are moftly obfervable in the 
trunk, being larger than in the root; and through a mi- 
■crofcope appear like fo many bubbles or bladders, as in 
a piece of burdock, fig. 477. 
In the piths of many roots and plants, fome of the 
larger pores or bladders have fmaller ones within them, 
fome of which are divided with crofs membranes, and 
between their feveral fides other fmaller bladders are In- 
ferted, in orderly ranks length-wile. 
What Dr. Grew calls fibres and infertments, or the 
lignous body interwoven with that which he takes to be 
the cortical, that is the feveral diftintftions of the grain, 
are called by Mr. Lifter veins ro , that is, fuch dui!fts as 
feem to contain and carry in them their nobleft juices, 
analagous to human veins. Mr. Lifter makes it appear, 
that thefe veftels are not the pores of the lignous body, 
from a tranfverfe feciion of angelica fylveftris magna vul- 
gatior; the veins there clearly difcovering themfelves to 
be diftintft from the fibres, obfervable in the parenchyma 
of the fame cortical body, the milky juices always riling 
on the fide, and not in any fibre. Alfo in a like irtffifion 
of burdock, in June the juice fprings on each fide the 
radii of the woody circle, that is, in the cortical body 
and 
m Phil. Tranft No. 75. 
