EUMEX DOCK. 



237 



lanceolate or cordate, 5 to G inches long ; stem leaves much smaller and on 

 shorter petioles. 



Habitat. — In the Rocky Mountain region and northward ; common also 

 in Northern Europe and Asia. 



Parts Used — Of P. bistorta the root ; of the other species, the herb — 

 none are official. 



Constituents. — Bistort contains a large percentage of tannic and gallic 

 acids. Water pepper and water smartweed possess an ' acrid principle 

 termed polygonic acid, to which 

 they owe their medicinal virtues. 

 This acid is also present in many 

 other species of the genus, in a 

 greater or less percentage. 



Preparations. — Bistort is ad- 

 ministered in powder, decoction, or 

 extract. Water pepper and water 

 smartweed are commonly adminis- 

 tered in decoction, but as their ac- 

 tive principle is dissipated by heat 

 or long keeping, an alcoholic tinc- 

 ture, made from the fresh plant, 

 is the best form in which to pre- 

 serve them for any great length 

 of time. In the country they are 

 gathered and dried annually for 

 domestic use, and do not seem to 

 lose much of their efficiency dur- 

 ing the few months that they are 

 kept. 



Medical Properties and Uses. — 

 Bistort is used both topically and 

 internally as an astringent, in the same manner as many other drugs rich in 

 tannin. Water smartweed and water pepper have a burning, biting taste, 

 inflame the skin when rubbed upon it, and possess somewhat acrid stimu- 

 lating properties. They are employed in domestic practice, externally as 

 counter-irritants, and internally to promote the menstrual flow, to induce 

 diaphoresis in acute inflammatory affections, etc., in the same manner as 

 other acrid and stimulating drugs are used. 



RUMEX.— Dock. 



Fig. 151.— Polygonum Bistorta. 



Character of the Genus. — Calyx of G sepals in two series of 3 each ; the 

 outer series herbaceous, the inner larger, somewhat colored, increasing in 

 size after flowering, and converging over the triangular achenium. Stamens 

 G, styles 3 ; stigmas tufted. Herbaceous plants, many of them pestiferous 



