186 EXOGONIUM PURGA 



then fusiform. It is readily distinguished from true jalap by its 

 paler colour and more woody character ; it is also commonly more 

 shrivelled and of lighter weight. Its essential constituent is a 

 resin, to which the name of Jalapin has been unfortunately given, 

 and which may be obtained from it to the extent of about 12 per 

 cent. When pure Jalapin is colourless, amorphous, translucent, 

 and perfectly soluble in ether, by which it differs from Convolvulin. 

 It is regarded by chemists as identical with scammony resin, and 

 hence, probably this kind of jalap is but little, if at all inferior, as 

 a medicinal agent, to that of true jalap. 



Medical Properties and Uses. Jalap is a certain, powerful, and 

 speedy drastic purgative, causing copious watery stools. It is 

 less irritant than gamboge, podophyllum, or even scammony ; but 

 it occasionally causes griping, aud sometimes nausea and vomiting. 

 It is frequently given to children as a vermifuge, on account of 

 its little taste, and generally safe action. It is a valuable purga- 

 tive in habitual constipation, and in febrile and inflammatory 

 affections, especially when combined with aromatics which diminish 

 the griping ; it is also given as a hydragogue in dropsies, as a 

 derivative purgative in head affections, and in other cases. 



Per. Mat. Med., vol. ii, pt. 1, p. 614 ; Per. Mat. Med., by B. & R., 

 p. 634; Pharmacographia, p. 399; U. S. Disp., by W. & B., 

 p. 501 ; Guibourt, Histoire des Drogues (1869), vol. ii, p. 523 , 

 Gmelin's Chem., vol. xvi, pp. 154 & 159; Hanbury, in Journ. 

 Linn. Soc. Bot. (1871), p. 279; Umney, in Pharm. Jl., vol. ix, 

 2nd ser., p. 282 ; Evans, in Pharm. Jl., vol. ix, 2nd ser., p. 330 ; 

 Squibb, in Amer. Journ. of Pharm., Jan., 1868, pp. 65-6 ; Amer. 

 Journ. of Pharm., vol. ii, p. 22, and vol. x, p. 224 ; Watts' Diet. 

 Chem. vol. ii, p. 15. 



DESCRIPTION OF PLATE. 

 Drawn from a specimen in the Royal Gardens, Kew, flowering in September. 



1. Part of stem, with flowers and leaves. 



2. Vertical, and 3. Transverse section of ovary. 



4. Stigma. 



5. Base of the stern and tubercular roots. 



