RADIX JALAPS. 447 



In chemical constitution Orizaba root is closely parallel to jalap. 

 The resin was named by Mayer Jalapin; it is the Jalapin of Gmelin's 

 Chemistry (xvi. 405), and perhaps the jalapin of English pharmacy. ^ 



In the pure state it is a colourless amorphous translucent resin, dis- 

 solving j)€rfectly in ether,"* thus differing from convohiilin the corres- 

 ponding resin of jalap. We find that it is readily soluble also in acetone, 

 amylic alcohol, benzol and phenol, not in bisulphide of carbon. It has 

 the composition of 0"H^0^^ so that it is homologous with convohnilin; 

 the decomposition-products of jalapin obtained by similar treatment, 

 namely jalapic acid, jalapinol, and jalapinolic acid, are likewise homo- 

 logous with the corresponding substances obtained from convolvulin. 

 All these bodies when treated with nitric acid yield ipomceic acid. 

 Jalapin has the same fusing point as convolvulin, and behaves in the 

 same manner with alkalis. 



The root afforded us 118 per cent, of resin dried at 100° C. When 

 perfectly washed, decolorized and dissolved in two parts of alcohol, this 

 resin turned the plane of polarization of a ray of light 9 8° to the left, 

 in a column of 50 mm. long. Convolvulin under the same conditions 

 turned it only 5"8\ The resin of Orizaba root is held by chemists to 

 be identical with that of scammony, of which it has the drastic action. 



2. Tampico Jalap, — Purga de Sierra Gorda of the Mexicans. — The 

 plant which affords this drug has been described by one of us (1869) 

 under the name of Iporaoia siriiulans? It is clasely related to /. Purga 

 Hayne, from which by its foliage it cannot be distinguished, but it has 

 a hell-sJuiped corolla and pendidoitsjlou'erbuds, which are very different. 

 /. siniulans Hanbury grows in Mexico along the mountain range of the 

 Sierra Gorda in the neighbourhood of San Luis de la Paz, from which 

 town and the adjacent villages its roots are carried down to Tampico. 

 It has also been found on the lofty Cordillera near Oaxaca, but whether 

 there collected we know not. 



The drug, to which in trade the name Tampico Jalap is commonly 

 applied, has been imported during the last few years in considerable 

 quantities. In appearance it closely approaches true jalap, but the roots 

 are generally smaller, more elongated or finger-like, more shrivelled and 

 corky-looking, wanting in the little transverse scars that are plentifully 

 scattered over the roots of true jalap. Many pieces occur however which 

 it is impossible to distinguish by the eye from true jalap, with which it 

 agrees also in odour and taste. 



Tampico jalap yielded to one of us 10 per cent, of puinfied resin, 

 entirely soluble in ether. Unmey* obtained 12 to 15 per cent, of resin 

 almost wholly soluble in ether ; Evans got 13 per cent., but found only 

 about half of this to be soluble in ether.* According to Andouard^ the 

 resin of Tampico jalap is not deficient in purgative powers. 



^ The name is ill-chosen and misleading, affording Tampico Jalap, Journ. of Linn. 



but having been adopted in standard works, .Soc, Bot. xi. (1S71) 279, tab. 2; Pharm. 



it might occasion greater confusion to Journ. xi. (1870) S48 ; American Jovrn. of 



attempt to supersede it, and its several Pharm, xviii. (1870) 330 ; Science Papers, 



derivatives. 1876. 349. 



-It is at least a fact, that of numerous * Pharm. Journ. ix. (1868) 282. 



.samples of jalapin that we have examined « Ibid. ix. (1868) 330. 



(1871), every one is compktely soluble in ^ Etude sur Us ConvoltiUaciea purgatives 



«'/««'•• (these) Paris, 1864. 31. 



3 Hanbury, On a species of Ipomcea, 



