GROWTH OF WOOD IN THE STEM. 27 
examine the appearance it presents; in the middle will 
be seen a mass of fine pith-like substance, which is 
surrounded by a greenish band. Next, examine a 
cutting of a piece of the stem, which is immediately 
below this young shoot, which part will have a brownish 
bark upon it, as it is a shoot of last year’s growth: in 
this instance, the pith will be found to be smaller than 
in the shoot of this summer, or of the present year; 
there will be seen also a white woody ring, surrounding 
the pith, and outside this woody part, the thick covering 
or bark will be found to be green inside, and brown 
on the outside. A third cutting should then be made 
just below where this branch is given off from the tree; 
in this instance, the pith will be perhaps rather less, the 
woody substance will be found to present a wider space 
round the pith, and the whole thickness of the shoot 
will be greater; there will be also a thick layer of bark 
outside the woody part. In this manner, the examina- 
tion may be carried on still further, and it will be seen 
that each part, as it is situated lower down, is thicker 
than that above it, as it has been formed a year or a 
season before, and if a smooth even cut is made across 
a stem, about half an inch in thickness, there will be 
seen just as many rings of wood surrounding the pith, 
as this part has been years growing. This will be 
better understood by referring to pl. 10. in which f. i. 
is half a eross cutting of a one year’s stem of a maple 
magnified, which at m. represents a part near the centre, 
and in which a number of large round openings may 
be seen, which are vessels of the plant, cut across; 
this part will ultimately become the wood of the first 
