92 
WOOD AND BARK OF TREES. 
that though it is really nothing but a piece of wood so placed, 
(that must originally have been of the same hardness as the 
rest) but it is converted, (by means of this softening liquid,) to 
the appearance of a most beautiful white leather. Then , 
indeed, conviction usurps the place of fancy, and we become 
assured that we guessed right. How strange, then, to alter 
all this beautiful arrangement — justified ( indeed taught ) by 
dissection, in order to find a place of circulation for sap-vessels, 
No returning that cannot possibly require any ; for why must they have 
barl^ S in ^ return i n g vessels ? Is there not a great difference between 
an animal which, after the first few years, has no increase, 
and a being that increases from every joint ; and may be sup- 
posed, therefore, to draw up only those juices necessary for 
that increase, especially as the sap is the liquid of the earth, 
not the blood of the tree, as is easily proved by adding nur- 
ture to the ground when the sap fails , which soon restores it ; 
besides, how is the circulation to be effected in the eternally 
decreasing branches of a tree, whose every additional twig 
must make a variation in the quantity of juices wanted ; 
whereas, it is naturally decreased as it mounts by the throwing 
out new shoots and branches, which expend the liquid as it 
Two wian- rises. But there are two, 1 may say, unanswerable arguments, 
"umentT ^ at must P ut an en< ^ to existence of such a system. 1 st. If 
there were such a law as gives circulation to the sap, instead 
of the power which merely carries up the quantity of liquid 
wanted for the use of the tree, it would be universal in all 
plants 5 it would be common to all without restriction. Now, 
there are a vast number of plants that lose their bark every 
winter, and renew it in the spring j but when the bark is gone, 
the inner bark-vessels (full of their juice) are still seen pressing 
to the wood— but what would become of the returning sap- 
vessels ? They could not do the same, or their quantity would 
have made a large portion of itself, and filled out the bark. 
No vessels to which they certainly do not do ; for there are no vessels to be 
be found. found but those I have mentioned — even the rind disappears 
in many plants. The vine is one of these, and many other 
twining plants. All the pentanilrian plants lose their bark 
long before they have formed their seed. Numbers of the 
syngenesian plants begin very early to lose it ) but as it dis- 
appears, leaving the rind, few who do not examine and cut 
plants 
