G78 AROIDEiE. 



extended epiblema-cells or of a brown corky tissue, the latter occurring 

 in the parts free from leaf-scars. The prevailing tissue, both of tlie 

 outer and the central part, consists of uniform nearly globular cells, 

 traversed by numerous vascular bundles, especially at the boundary 

 line (medullary sheath). Besides them, the rootstock like that of many 

 fresh- water plants, exhibits a large number of intercellular holes. These 

 air-holes, or more correctly water-holes, are somewhat longitudinally 

 extended, so as to form a kind of net-work, imparting a spongy con- 

 sistence^ to the fresh rootstock. At certain places, where the series of 

 cells cross one another, especially in the outer part, there are single 

 cells filled with essential oil,^ which may be made very conspicuous by 

 adding to sections dilute potash or perchloride of iron. The other cells 

 are loaded with small starch granules ; a little mucilage and tannic 

 matter is met with in the exterior coat. 



Chemical Composition — The dried rhizome yielded us 1"3 per 

 cent, of a yellowish neutral essential oil of agreeable odour, which in a 

 column of 50 mm. long, deviates 13 "8° to the right. By working on a 

 large scale, Messrs. Schimmel & Co., Leipzig, obtain 2'4 to 2'6 per 

 cent. 



According to Kurbatow (1873), this oil contains a hydrocarbon, 

 C^*'H"', boiling at 159° C, and forming a crystalline compound wuth HCl, 

 and another hydrocarbon boiling at 255-258° C, affording no crystal- 

 lizable hydrochloric compound. By submitting the oil to fractional 

 distillation, we noticed, above 250°, a blue portion, which may be de- 

 colorized by sodium. The crude oil acquires a dark brownish colour 

 on addition of perchloride of iron, but is not at all soluble in concen- 

 trated potash solution. 



The bitter principle Aconn was extracted by Faust in 1867, as a 

 semifluid, brownish glucoside, containing nitrogen, soluble both in ether 

 and in alcohol, but neither in benzol nor in water. In order to obtain 

 this substance, we precipitated the decoction of 10 lb. of the drug by 

 means of tannic acid, and followed the method commonly practised in 

 the preparation of bitter principles. By finally exhausting the residue 

 with chloroform, we succeeded in obtaining a very bitter, perfectly 

 crystalline body, but in so minute a quantity, that we were unable to 

 investigate its nature. 



Uses — Sweet Flag is an aromatic stimulant and tonic, now rarely 

 used in regular medicine. It is sold by the herbalist for flavoui'ing 

 beer, and for masticating to clear the voice. It is said to be also used 

 by snuff manufacturers. 



Adulteration — The rhizome of the Yellow Flag, Iris Pseuckicorus 

 L., is occasionally mixed with that of the Sweet Flag, from which it 

 may be distinguished by its want of aroma, astringent taste, dai"k 

 colour, and dissimilar structure. 



1 This was possibly alluded to by Alber- Jessen's ed. 1867. 376. We suppose the 



tus Magnus (a.d. 1193-1280), who says : — drug under notice was intended. 



(Calamus aromaticus) — nascitur in India ^ Hence the practice of peeling the 



et Ethiopia sub cancro, et habet interius rhizome which prevails in some parts of 



ex parte concava ' ' pellem subtilem, sicut the Continent ought to be abandoned. 

 telce sunt aranearum." — De Vegetabilibus, 



