220 LEGUMINOSiij:. 



astringent. In water or strong alcohol it is almost insoluble, and 

 entirely so in ether or chloroform ; but it dissolves in warm dilute 

 alcohol. From this solution it is precipitable by many acids, but not 

 by tannic. 



Groves^ in 1868, unaware of the researches of DragendorfF and 

 Kubly, arrived at similar results as these chemists, and proved con- 

 clusively that a cathartate of ammonia possesses in a concentrated form 

 the purgative activity of the original drug. 



The exactness of the chief facts relative to the solubility in weak 

 alcohol of the active principle of senna set forth by the said chemists, 

 was also remarkably supported by the long practical experience of 

 T. and H. Smith of Edinburgh.' 



When cathartic acid is boiled with alcohol and hydrochloric acid, it 

 is resolved into sugar and Cathartogenic Acid. 



The alcoholic solution from which the cathartates have been separated 

 contains a yellow colouring matter which was called Ghrysoretin by 

 Bley and Diesel (1849), but identified as Chrysophan^ by Martius, Batka 

 and others. Dragendorff and Kubly regard the identity of the two 

 substances as doubtful. 



The same alcoholic solution which contains the yellow colouring 

 matter just described, also holds dissolved a sugar which has been 

 named Catharto-mannite. It forms warty crystals, is not susceptible 

 of alcoholic fermentation, and does not reduce alkaline cupric tartrate. 

 The formula assigned to it is C^H^O^. 



Senna contains tartaric and oxalic acids with traces of malic acid. 

 The large amount of ash, 9 to 12 per cent., consisting of earthy and 

 alkaline carbonates, also indicates the presence of a considerable quantity 

 of organic acids. 



Commerce — Alexandrian Senna, the produce of Nubia and the 

 regions further south, was formerly a monopoly of the Eg^-ptian Govern- 

 ment, the enjoyment of which was granted to individuals in return for 

 a stipulated payment : hence it was known in continental trade as 

 Sene de lapalte, while the depots were termed pcdtes and those who 

 farmed the monopol}'^ paltiers* All this has long been abolished, and 

 the trade is now free, the drug being shipped from Alexandria. 



Arabian senna is brought into commerce by way of Bombay. The 

 quantity of senna imported thither from the Red Sea and Aden in the 

 year 1871-72 was 4,195 cwt., and the quantity exported during the 

 same period, 2,180 cwt.^ 



Uses — Senna leaves are extensively employed in medicine as a 

 purgative. 



Adulteration — The principal contamination to which senna is at 

 present liable arises from the presence of the leaves of Solenostemma 

 Argel Hayne, a plant of the order Asclepiadece, 2 to 8 feet high, grow- 

 ing in the arid valleys of Nubia. Whether these leaves are used for the 

 direct purpose of adulteration, or under the notion of improving the 

 drug, or in virtue of some custom or prejudice, is not very evident. It 



^ Pharm. Journ. x. (1869) 196. * Statement of the Trade and Navigation 



^Jbid. 315. of t?ie Presidency of Bombay for 1871-72, 



3 See Art. Budix Bhei. pt. ii. 21. 98. 

 * From Italian appaltare, to let or farm. 



