JIADIX JALAPS. 



447 



In the pui^e state it is a colourless amorplious translucent resin, d'ni- 



f 



thus clitFering from convolvulin the corren- 



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



benzol 



It has 



the composition of C'^II^'O^", so that it is homologous with convolvulin ; 

 the decomposition-products of jalapin obtained by similar treatment, 

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

 logous with tlie corresponding substances obtained from convolvulin. 

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

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

 same manner with alkalis. 



The root afibrded us 11 '8 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 eohnun 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 seammony, of which it has '(h^ drastic action. 



2. Tampico Jalap,— Piirga de Sierra Gurda of the Mexicans.— The 

 plant which affords this drug has been described by one of us (1600) 

 under the name of Ipoma'a simulani^.^ It is closely related to /. Purja 

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

 a hell-sJurped corolla SLiidpendulousflou'erhuds, which are very ditil-rent. 

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

 Sierra Gorda in the neighbourhood of San Luis de la Paz, frozii A\hich 

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

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

 there collected we know not. , 



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

 applied, ha.s been imported during the last few yeai-s ni considerable 

 quantities. In appearance it closely approaches true jalap, but tlie root.s 

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

 corky-looking, wantincr in the little transverse scars that are plentiiuUy 

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

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

 agrees also in odour and taste. „ . ,. , 



Tampico jalap yielded to one of us 10 per cent, of purM rosi 

 entirely soluble in ether. Umney* obtained 12 to 15 per cent, ot resi 



esin 



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

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

 resin of Tampico jalap is not deficient in purgative powers. 



, .T "*i"e is iil-choscn aiul misleailing, 

 put having l.eeji adopted in stiuidaid works. 

 It inight occasion greater coDfusion to 

 attempt to supersede it, and its several 

 derivatives. 



It is at least a fact, that of ninnerous 

 ns-i ^^ of jalapin that we have examined 

 U»/I), every one is compleUhj xohihle in 



Hanbury, On a species of Jpomita, 



affording Tampico Jalap, Jvnrn. of Lu,n. 

 Soc, Bo°t. xi. (1S71) 279, tab. 2 ; Phann 

 /nun, xi (1870)848; vlw^'-'WH/oci'v/.o/ 

 Srm.fviu. {1870):«0; .S-c-;..« Papn:, 



-* Phann. Jonru. ix. (ISGS) 282, 

 «//.W. ix. (lS()8):m 



(th^se) Paris, 1864. 31. 



