80 
COURSE OF THE SAF. 
[Part IT. 
Whether the 
pith is the con¬ 
duit of the 
upward sap 
or not. 
have been some time cut, small cracks in the 
direction of the silver grain meet at the pith, 
and prevent its being seen. This accidental 
disappearance of the pith, immediately on the 
death of the tree, is another corroboration of the 
vulgar belief of the death and disappearance of 
the pith during the life of the tree. Every in¬ 
numerable small side-twig of every innumerable 
small branch and root of the most gigantic oak, 
gives origin to a new series of annual cones of 
growth; and until internal death and decay 
supervene, the first annual pith of the original 
seedling communicates with these countless ra¬ 
mifications of branch and root, and by its direct 
and lateral elongations passes, through the tops 
of these innumerable myriads of cones, to every 
side or leading bud, and to near the termination 
of every the finest ramification of the roots. 
Many of the older, and some existing physi¬ 
ologists, maintain that the upward sap is solely 
transmitted by the pith; and the fact I have 
stated seems to favour the opinion that the pith 
may play a prominent part in supplying the 
bud, leaf, and new shoot with upward sap : but 
how could the eleven layers of new wood, which 
sheathed the sides of the ringed branch, have 
been kept moist with sap, except by lateral 
