C O N V O L V U L A C E JE. 



135 



The simple beauty of the smooth fresh green leaves, 

 surrounding and serving as a background to the ele- 

 gant racemes of pure white nodding flowers, is a con- 

 trast which enhances the value of both. Those who 

 are the least sensible of the beauty of flowers, appear 

 charmed with the simple elegance of the lily of the 

 valley. So much has it been cultivated in every gar- 

 den, that two varieties have been already obtained, 

 namely, the red flowering and the double ; all of which 

 are easily increased by division, and will thrive in any 

 shady place. 



CONVOLVULACE.E. The bindweed family. 

 A natural order of dicotyledonous plants, containing 

 upwards of twenty genera, and between two and 

 three hundred known species. Its plaited corolla, 

 and climbing habit, are the characters by which this 

 order is best distinguished from all others. It bears 

 an affinity to Cordificfic- in its shrivelled coulcdons, 

 and it is also allied to /'<,/, nd IIydn>l< 



Its essential chancters are : calyx with five 

 divisions, persistent ; corolla mqnopetalou?, hypogy- 

 nous, regular, the limb five-cleft, generally plaited 

 and deciduous ; stamens live, inserted at the bottom 

 of the corolla, and alternate with its segment? ; ovary 

 single, two to four-celled, rarely one-celled, some- 

 times in two or four divisions, with few definite erect 

 ovules ; style one, often divided at the apex, some- 

 times as far as the base ; stigmas obtuse or acute ; 

 capsule one to four-celled, the valves corresponding 

 to the angles of a free dissepiment, bearing the seeds 

 at its base, sometimes without valves, or opening 

 transversely; seeds with a small quantity of mucilagin- 

 ous albumen ; embryo curved ; cotyledons wrinkled ; 

 radicle inferior. 



The plants belonging to this order are herbs or 

 shrubs, which are usual! v climbing, milky, smooth, or 

 with a simple pubescence. Their leaves are alternate 

 undivided or lobed, without stipules, and their in- 

 florescence terminal or axillary. They have fre- 

 quently showy flowers, which expand beneath the 

 influence of bright sunshine. They are found twining 

 round other phmts, or creeping among weeds on the 

 sea-shore in the tropical regions of the globe, and are 

 by no means abundant in cold climates. Their roots 

 abound in an acrid milky resinous juice, possessing 

 purgative qualities. Some of them are employed as 

 articles of food. 



The chief genera of the order are, Convolvulus, 

 (W;/.s/Viw, Ipomcea, Cuscuta, Evolvulus, Argyreia, 

 Falkia, and Rftzia. 



Convolvulut, bindweed, is a very extensive genus, 

 and includes some species which are prized on 

 account of their beauty, or the valuable products 

 which they furnish. 



Convolvulus, or Ipomcea jalapa, is a climbing peren- 

 nial plant, found near Xalappa, a town of Mexico. 

 It was first brought to Europe in 1610. The root of 

 the plant furnishes (he medicinal jalap. It is a 

 tuberous egir-shaped root, which, when fresh, is white 

 and lactescent, but, as imported, is generally covered 

 with a blackish wrinkled bark. It is sometimes 

 brought to this country in the form of thin transverse 

 slices, having a greyish colour internally. The 

 tubers, when sound, are compact, hard, and heavy, 

 and break with a resinous fracture. They have a 

 nauseous taste and smell, and seldom exceed a few 

 ounces in weight, with a diameter of two or three 

 inches. When powdered, jalap has a yellowish grey 

 colour. 



The roots of common bryony, the marvel of Peru 

 (MirabJ&s jalapa), and of other species of convol- 

 vulus, are often mixed with those of the true jalap. 



Jalap has been ascertained by analysis to consist 

 of resin, extractive matter, starch, vegetable albumen, 

 woody fibre, and various salts. A substance has lately 

 )een obtained from jalap possessing powerful purga- 

 ivo properties, and which, from being considered its 

 active principle, has been denominated Jalapine. 

 The observations made in regard to it however, are 

 not as yet satisfactory. 



The properties of jalap reside chiefly in the resin. 

 When administered in small doses, of ten or fifteen 

 grains, this medicine is an effectual, safe, and mild 

 purgative ; but when given in large doses it produces 

 griping, watery evacuations, and may even excite 

 inflammatory action. Camphor is one of the best 

 substances for preventing its griping effects. It is 

 frequently prescribed in combination with calomel 

 and cream of tartar. When mixed with two parts of 

 the latter salt, it constitutes the compound jalap 

 powder of the Edinburgh Pharmacopoeia. 



The watery extract of jalap possesses the proper- 

 ties of the root in a weak degree. The resin, by 

 itself, produces distressing symptoms, without much 

 eii'eet in evacuating the bowels. Diluted alcohol, or 

 proof spirit, dissolves almost all the active ingredients 

 of jalap. 



The root of Convolvulus pan.dural.us is used in the 

 United States as a substitute for jalap. 



Convolvulus team-mania (scammony), is another 

 climbing species of bindweed, found in the Levant, 

 Syria, and Turkey, and growing abundantly on the 

 mountains between Aleppo and Latakia. The roots 

 of this plant are three or four feet long, and nine or 

 twelve inches in circumference, and when cut yield 

 a milky juice, which concretes, and forms the gum- 

 resin known in medicine by the name of scammony. 

 The following is the mode in which the gum-resin is 

 collected : The earth being removed from the upper 

 part of the root about the month of June, an incision 

 is made obliquely across it, and the milky juice which 

 exudes is allowed to flow into a shell or cup placed 

 at the lower end of the cut. Afcer the vessel has 

 been left for twelve hours, it is removed, and the 

 concrete juice is taken out. Each root yields only a 

 few drachms. The produce of several routs is then 

 collected, and put into packages or drums, as they 

 are called, which weigh from 75 to 125 pounds. The 

 best scammony is brought from Aleppo. An inferior 

 sort is exported from Smyrna in the form of cakes, 

 like wax, packed in chests. This would appear to be 

 the produce of another plant, Pcriploca scammonium. 



Scammony is frequently adulterated with sand, 

 ashes, and the juice of other plants, such as ci/nanclnim, 

 monspeliacum, &c. The Smyrna scammony is said 

 to be sometimes an entirely artificial compound, con- 

 taining no real scammony whatever. 



Pure Aleppo scammony occurs in the form of 

 light, spongy, friable masses, having a heavy di-- 

 areeable smell, a bitter acrid taste, and a blackish cr 

 dark grey colour. When broken, it exhibits a smooth 

 somewhat shining fracture, and when powdered is of 

 a light grey, or whitish colour. Scammony consists 

 of resin, gum, and extractive matter. It possesses 

 powerful purgative qualities, which reside in the 

 resin, of which it is chiefly composed. It is ad- 

 ministered in doses of five or ten grains, and is 

 frequently prescribed in combination with calomel, 



