cells;--'cambium' for an early state of _both_, and 'diachyma' for a
peculiar position of _one_![46] while the chemistry of all these substances
is wholly neglected, and we have no idea given us of any difference in
pith, wood, and bark, than that they are made of short or long--young or
old--cells!

22. But in Dr. Gray's 230th article comes this passage of real value.
(Italics mine--all.) "While the newer layers of the wood abound in _crude_
sap, which they convey to the leaves, those of the inner bark abound in
_elaborated_ sap, which _they receive from the leaves_, and convey to the
_cambium_ layer, or _zone of growth_. The proper juices and peculiar
products of plants are accordingly found in the foliage and bark,
especially the latter. In the bark, therefore, either of the stem or root,
medicinal and other principles are usually to be sought, rather than in the
wood. Nevertheless, as the wood is kept in connection with the bark by the
medullary rays, many products which probably originate in the former are
deposited in the wood."

23. Now, at last, I see my way to useful summary of the whole, which I had
better give in a separate chapter: and will try in future to do the
preliminary work of elaboration of the sap from my authorities, above
shown, in its process, to the reader, without making so much fuss about it.
But, I think in this case, it was desirable that the floods of pros-, par-,
peri-, dia-, and circumlocution, through which one has to wade towards any
emergent crag of fact in modern scientific books, should for once be seen
in the wasteful tide of them; that so I might finally pray the younger
students who feel, or remember, their disastrous sway, to cure themselves
for ever of the fatal habit of imagining that they know more of anything
after naming it unintelligibly, and thinking about it impudently, than they
did by loving sight of its nameless being, and in wise confession of its