Rumex Crispus — Yellow Dock. 409 
dition briskly boiling for 10 or 15 minutes, before the bitter astrin- 
gent principles could be all taken up. 
On subjecting the green root to a temperature of 212° in a 
partially closed vessel, it turns to a dark brown color, and gives 
off a very strong pungent odor, like that of the root. The same 
odor, but less intense, is given off from it when boiled in water 
or alcohol. By long continued boiling, the pungent bitter pro- 
perties become greatly diminished in consequence of their vola- 
tility. They can be distilled over with water, giving to that 
liquid the odor of the root and a light yellow color. A yellowish 
gummy mass remains on evaporating at a low temperature, which 
I have not had time to examine further. The medicinal virtues 
of the root probably depend in a great measure upon the volatile 
matter; if so, by subjecting it to protracted heat in any way, 
must tend to diminish its activity as a medicine. 
I have not yet succeeded in obtaining an extract as bitter as 
the decoction at the commencement of the evaporation. The bit- 
ter principles seem to escape during the evaporation of the liquid, 
leaving a residue which is less bitter than the solution started 
with, but more nauseating. The examination of this plant w^ill 
be continued. 
Remarks. — By the foregoing analyses the farmer will at once 
perceive what constituents of the soil are taken up by this pest 
of our fields. It will be observed that it partakes largely of the 
phosphates, robbing our cultivated plants of their richest food. 
But as much as this plant is now detested by the agriculturist, it 
may yet be turned to his advantage, and may become a favorite 
and profitable plant among his cultivated crops. 
It has always been known to possess medicinal qualities, and 
of late has been extensively used in syrups, &c. Persons are 
employed to procure the roots, for which three cents a pound is 
paid for them in a green state. When dried, twelve cents a 
pound is allowed by some of our druggists. 
Our attention was first directed to this subject on being applied 
to for the privilege of taking the dock from our fields. This we 
very readily assented to, rejoicing in the fact of having them 
taken from our fields without any expense. 
The proper time to pull them is when in flower, and immedi- 
ately after a rain, while the soil is moist, as they can then be 
