CONVGLVULACE^E. 475 



Linnaeus, however, in the first edition of his Materia Medica, adhered to the 

 opinion of Tournefort, and attributed it to the Mirabilis longiflora. Some 

 years afterwards he recognised his error, and placed it in the genus Convol- 

 vulus, under the specific name of Jalapa (Mant. i. 42) ; this, as before noticed, 

 is now shown to be the same as the Ipomcea macrorhiza. Murray (Appar. 

 Med. i. 216), on the authority of Thiery de Menonville, thought that there 

 might be more than one species of Convolvulus furnishing the officinal jalap, 

 the latter having stated that he found a species near Vera Cruz, which he 

 affirmed to be the true jalap, and the roots of which weighed 25 pounds. 

 He drew up a description of this plant, and transmitted it to Jussieu and 

 Desfontaines, and the latter, on comparing it with that of the Ipbmcea ma- 

 crorhiza, specimens of which were growing in the Garden of Plants at Paris, 

 was convinced that the plants were identical ; hence when Michaux discovered 

 the latter in Florida, and sent the seeds to Paris, Desfontaines published a 

 memoir (Ann. du Mus., ii. 220), in which he described it as I. macro- 

 rhiza, and gave the C. jalapa of preceding botanists as synonymous ; 

 this opinion was adopted by Pursh, W. P. C. Barton, and others, but the 

 accuracy of it was first doubted by Mr. Elliott (Sketches, i. 253), on the 

 authority of Dr. Baldwin, as has been already stated. 



In 1827, Dr. J. R. Coxe having received roots of the true jalap from South 

 America, published an account of it (Am. Jour. Med. Sci., 1830), but unfor- 

 tunately under the name of Ipomcea jalapa vel macrorhiza. In 1829, M. 

 Ledannois sent a short description of the same plant to M. Chevallier at Paris. 

 The same year in which Dr. Coxe's account of it appeared, it was also 

 described by Dr. Schiede (Linnea, v. 473), and Dr. Wenderoth (JPharm. 

 Centralb. i. 457), under the_name of I. purga, and described and figured by 

 Zuccarini in 1832. -(Act. Acad. Reg. Monac. x.) To conclude this subject, 

 it may be stated that in 1837 Dr. Wood received tubers of the true plant 

 from Vera Cruz, which produced plants having the same characters as those 

 described by Dr. Coxe, and also that these roots had all the sensible pro- 

 perties of the officinal drug (Carson, Am. Jour. Pharm. iv. 28). The ques- 

 tion may therefore be considered as settled, and the I. purga looked upon as 

 the officinal species. It should be noticed that Dr. Christison (Proceed. Bot. 

 Soc.) states that specimens derived from Dr. Wood's plants do not exactly 

 coincide with the plates of I. purga as figured by Hayne, or I. Schiediana, 

 Nees, (non Hamilton, Bot. Reg. 1838.) 



It only remains to make a few observations on the representations given ; 

 that of Lemery is so bad that it is impossible to decide whether it is intended 

 for a Convolvulus or a Mirabilis. The C. jalapa of Woodville resembles 

 very closely one of the varieties of i". pandurata ; that of the Botanical Ma- 

 gazine, 1572, and of Desfontaines (/. c.}, are figures of B. jalapa. The 

 true plant is figured in the American Journal Med. Sci. (I. c), and AmerU 

 can Dispensatory, 1S30 ; in Botanical Register, 1839 ; by Nees, Off. Plan., 

 Supp. 3, t. 13. 



The root, as found in the market, is in pieces of various forms and sizes ; 

 when entire, they are more or less oval, but are generally in slices. The 

 epidermis is thin and brown ; and when they are broken, of a deep yellowish- 

 gray colour, with brown, concentric rings. They should be heavy, hard, and 

 difficult to powder, but there is much variation even in the true Jalap ; besides 

 which it is adulterated with what is called Male Jalap, first described by M. 

 Ledannois, and supposed to be the product of the I. orizabensis, Stendel. 

 Jalap is also liable to be worm-eaten, but this does not injure its purgative qua- 

 lities. The odour of Jalap is nauseous, and the taste sweetish, sub-acrid, and 

 unpleasant. From the various analyses of it, it is shown to contain Resin, 



