TAMPICO JALAP. 349 



attempted in the south of France by Professor Dr. J. E. 1867. 

 Planchon, of Montpellier, and by M. Gustave Thuret, of Antibes, 

 but the summer climate of those localities is so much drier 

 than that of the region in which the jalap plant is indige- 

 nous, that success is doubtful. Tubers have also been sent to 

 Madeira. 



There is one other point in connection with this subject upon 

 which we seem to require information, and that is the age at which 

 the jalap tubers can be collected to most advantage. It is well 

 known that the jalap of commerce consists of tubers of all sizes 

 between those weighing a few grains up to such as weigh several 

 ounces ; and that the larger and those which are internally 

 most compact, dry and resinous are preferred. 



The adoption of a better method of drying the tubers than that Better mode 

 at present pursued will also deserve attention. It is probable that of 

 this object will be accomplished by slicing the tubers while 

 fresh, and drying them with the gentle heat of a stove. [N. Ee- 

 pert.f. Pharm. xvi. 421.] 



ON A SPECIES OF IPOMCEA, AFFOKDING TAMPICO 



JALAP. 



(With Plate.) 

 (Read at the Linnean Society, December 16th, 1869.) 



Two centuries and a half have elapsed since jalap, the 187O. 

 tubercule of a convolvulaceous plant of Mexico, was introduced 

 into the Materia Medica of Europe. The botanical origin of 

 the drug long remained unsettled, evidence of which exists in 

 the fact that two plants, neither of which yields jalap, have in 

 succession received, and still retain, the specific name Jalapa. 

 The veritable source of jalap, however, was brought to light 

 between the years 1827 and 1830, in which latter the plant was 

 described by Wenderoth as C(mvolwdus Purga. In 1833 it was 

 figured by Hayne under the name of Ipomcca Purga ; but in ipomosa 

 1839 it was transferred, on account of its tubular corolla and urga " 



