KEEGAN: CHEMICAL ANALYSIS OF CERTAIN ROSACEA. 25 
Great Burnet (Sanguisorba officinalis), The composition of this 
plant seems to vary with the season. Thus the stem and leaves 
obtained on July 17th were found free from tannin, but yielded a large 
quantity of a yellow colouring matter which gave all the reaction of 
rutin (quercitrin); but the same parts examined in early September 
revealed the presence of a tannin which was iron-blueing, precipitates 
gelatine and tartar-emetic, and resolvable into a red-brown phloba- 
phene by the action of dilute sulphuric acid. The flowers owe their 
tints to a pigment which is perhaps the most remarkable body of its 
kind in the whole order. Its extreme depth and vividness can only 
be duly appreciated when it is extracted and more or less isolated. 
It is evidently the product of a very high stage of oxidisation, as 
when the flowers are analysed they are found to contain a body 
which seems allied to, if not identical with, ellagotannin C,,H,,O,), 
which is the most highly oxidised of vegetable astringents. 
Blackberry (Rudus fruticosus). The leaves of this shrub are 
well prepared to withstand the winter chill, being richly charged with 
wax, fatty acids, and resinous matters. The alcoholic extract (after 
benzene) contains a tannin which yields no phlobaphene and gives 
the reactions of ellagotannin; there is also a resinous body which is 
probably identical with the coniferin of Tangl; there is very little 
proteid matter in the leaves, but the presence of mucilage, sugar, and 
starch is strongly evidenced. The colour of the stem seems to be 
due to paracarthamin Cy H,, O,,, which in winter exhibits a red tint 
(acid) on one side thereof, and a green tint (alkaline) on the 
Opposite side. The flower heads contain the same kind of tannin as 
the leaves, but its powerful tinctorial properties are apparently 
reserved till the fruiting period. The formation of the fruit is 
evidently attended with great oxidising energies, as the petals contain 
little or no soluble pigment (anthocyan), and the well-known ‘black’ 
(really dark red or purple) of the berries has very probably the same 
origin as the colouring matter of the flowers of the burnet and 
marsh cinquefoil. 
ommon Avens (Geum urbanum). There is nothing of posi- 
tive interest connected with this plant, the signal facts being that the 
flower pigment is totally independent of the leaves, and that there 
exists a small quantity of a tannin, which is probably quercitannin, 
Scarcely sufficient to impart any colouration to flower or leaf. 
Silverweed (Potentil/a argentea). There does not exist any 
tannin in any part of this plant, its place being taken by rutin, 
which exists in all parts. The colour of the petals is due to 
_ chromoleucites tinctured by carotin; and it is singular to notice 
how these bodies seem to appear always in corollas in cases where 
Jan. 1895. 
