1899] CHEMISTRY OF OUK FOREST TREES Cy 
splint-wood; the wood-elements seem only very slowly to become 
completely lignified, and although the ratio of “incrusting matter” 
therein is ultimately extremely high, there exists only a very small 
quantity of tannin and that only infiltrating the walls; in the inner 
rings there is a specially abundant store of starch laid up to meet the 
tremendous drain of the “seed-year,” this starch gradually changing 
into drops of wood-gum (xylan). Moreover, it requires more nitrogen 
than most other trees, and needs a plentiful supply of potash. The 
external economy, too, is as remarkable as the internal. The cortex is 
a veritable curiosity. “The whole tree,” says Wicke, “sticks, so to 
speak, in a siliceous coat of mail, the silica forming a thick solid crust 
over the whole stem and the young twigs.” The bark is said to con- 
tain 70 to 90 per cent of oxalate of calcium. Beech leaves are 
eminent for their large percentage of fatty matter, fibre, lime, silica, 
and manganese. In view of the considerable amount (some 25 per 
cent) of oil in the nut, the enormous affluence of starch, and the poor 2 
per cent of tannin in bark and leaves, we can have no hesitation in pro- 
nouncing the Beech to be the most vivaciously active and powerful 
assimilating organism of our woodlands. Finally, how it happens that 
the Spanish Chestnut should specifically and exclusively produce the 
particular. tannin called gallotannin in the bark and the wood (each 
contains about 7°5 per cent, the leaves about 6 per cent), is one of the 
mysteries shrouded beneath the impenetrable and inscrutable veil of 
forest secrecy. 
Passing by the Hazel, Walnut, etc., which are not strictly speaking 
forest trees, we now approach a mystic tenant of the woods, a true 
native, an? ‘abundantly familiar, but which challenges the utmost 
possible chemical consideration that can be bestowed upon it. This 
is the common Ash (Fraxinus excelsior), and no lynx-eyed acuteness is 
requisite to enable anybody to perceive that even exteriorly it differs 
immensely from its arboreal neighbours and confreres. The smooth 
olive-grey bark, the astonishing knotty protuberances of its bursting 
flower-buds in spring, the almost absolute freedom from any intrusive 
or brilliant colorific effect in any of its members or organs, are so many 
tokens and pledges of characteristics entirely uncommon. It is a 
starch-tree, but its seeds contain 16 per cent of oil and no starch, and, 
moreover, on analysis one finds in the various organs such a consider- 
able amount of waxy, resinous, and fatty matter, and such evidences 
of a facile decomposition of such carbohydrates as are produced in its 
leaves, that its claim to enrolment in the order Oleaceae is seldom 
questioned and never belied. In 1840 Gmelin had noticed a peculiar 
iridescence among the constituents of the bark of Fravinus Ornus ; but 
in 1856 Salm-Horstmar discovered a similar fluorescence in the 
infusion of the bark of F. excelsior, and in the following year he 
isolated, examined, and called it fravin. Its dilute aqueous solution 
exhibits by reflected daylight a strong blue or blue-green fluorescence 
