350 Keegan: The Chemistry of the Lakeland Trees. 
turpentine, it is of a greenish-yellow colour and saa an 
odour recalling that of a mixture of lavender and lem 
spen. Populus tremula, It seems rather difficult to 
believe that this species is truly native and prehistoric, yet there 
is no doubt whatever about the fact, its occurrence being 
recorded as ‘ frequent up to 900 feet in woods and hedges.’ It 
is extremely hardy and adaptable, although rather light-needing 
on account of its sparse leafage. The most remarkable feature 
about the Poplars is that they are fat-trees, whereas the Willows 
are starch-trees, i.e., while in the former the starch almost 
entirely disappears from all parts during the winter months, in 
the latter the starch remains at all times in the wood and pith, 
but it vacates the bark in winter. The Aspen is especially 
distinguished by the presence in its bark and leaves of a gluco- 
side called populin C*H*O%, which is allied to salicin (found in 
numerous Willows), but it contains the benzoyl radicle (i.e., it 
yields benzoic acid as well as saligenin on decomposition by 
dilute acids), has a sweet taste, decomposes with far greater 
facility, and is much less soluble in water and alcohol. In other 
respects the chemical composition of the two genera of the sub- 
order Salicackes is pretty similar. The ‘golden perch of Aspen 
spray’ in October is (Aree by the large amount of carotin 
which the leaves contai 
Oak. Quercus coker. This grand national tree flourishes 
in sturdy and stately grandeur in the woods and among the 
crags, the mountain winds contributing to impart a peculiar 
character of. pict uresque intricacy to the curiously tortuous 
branchlets, twisting: zigzagedly hereabouts even more than is 
their wont. As might be expected, this tree has been the 
subject of a vast amount of chemical research; but it is only. 
recently that its power as a starch-producer has been fully 
recognised, and this is the reason of its special liability to be 
struck by lightning. It will hardly be necessary to give a full 
recital of the numerous and interesting constituents of so well- 
known atree. The tannin of the wood is different from that in 
the bark and leaves, and approaches more decidedly that in the 
galls and acorns; it is what is called a digallic-methy]l ester or 
a derivative of pyrogallol, whereas that of the bark and leaves 
is phlobaphenic and a derivative of pyrocatechin. The bark 
contains from 6 to about 15 per cent. soluble and insoluble 
tannin, the parenchyma of the bast and the primary cortex being 
especially rich; in the wood it occurs sparingly up to about 
5 per cent. A trace of free gallic acid sometime occurs in the 
bark, which also contains phlobaphene, wax, pectin, levulin, 
quercite, starch, oxalate of calcium, and about 2 per cent. ash 
Naturalist, 
. 
