pee Sb pve ag 
Keegan: The Chemistry of the Lakeland Trees. 185 
eminently provocative of rheumatism, etc. Generally chee 
the crack Willows (.S. a/ba, etc.) contain more tannin, up to 8 o 
12 per cent., while the purple Willows (S$. helzx, S. iatuieen 
and S$. precox) contain more salicin, up to 4 percent. The latter 
principle is easily prepared, and when oxidised it yields sali- 
cylol, which smells like the flowers of Meadow-Sweet (SAzr@a 
wlmarta), and, in fact, the latter odour is due to the self-same or 
a nearly allied body. The tannin of the Willow is generally 
mixed with a little gallotannin, but in itself it is a glucoside 
somewhat like the tannin of the Oak bark, is iron blueing, 
and on potass-fusion yields protocatechuic acid and phloro- 
glucin. The leaves have pretty much the same composition as 
the bark, with much starch, gum, phlobaphene, and oxalate of 
calcium. 
h. Fraxinus excelsior. Our notice of this mystic tree 
must be regarded as of the utmost possible interest and 
importance. From every point of view the chemistry of this 
slim and airily-graceful native of our woodlands is worthy of 
special and prolonged study. In itself it is replete with most 
noteworthy features, which are doubly enhanced in instructive- 
ness when placed in contrast with those of its fellow-tenants of 
the forest. Notwithstanding its eminent picturesque beauty, its 
transparency, and the engaging play of light through its entire 
leafage, it is palpably and plainly seen in the most marked 
degree to be almost absolutely bereft of brilliant and telling 
colorific effects. Its bark is hoarily green, and never reddish- 
brown or chocolate-red; its buds and flowers are black or 
dark purple; and the autumn leaves, when not yellow, are of 
a muddy-brown unpleasant shade. e special and most 
interesting constituent of the bark is a glucoside called fraxin, 
C“H"O"1 aq., which possesses in a very marked degree the 
property of fluorescence, i.e., its aqueous solution is yellow 
when viewed by transmitted light, but by reflected light it 
appears lighted up by a strong and lustrous bluish-green colour. 
The tannin is totally different from that of any of our forest 
trees: it is distinctly iron-greening, does not precipitate era 
and on potass-fusion yields protocatechuic acid only. There is 
no phloroglucin or any of its derivatives in any of the tissues or 
organs. The leaves are richer in various chemical constituents 
than perhaps those of any other plant commonly known in our 
latitudes. They contain a fatty matter like olein, a resinous 
body, tannin, quinic and malic acids, an alcohol called inosite, 
also > mannite, Sater and ag aad about 6 to 9g per cent. 
June 1898. 
