AROTDEJ^. 541 



tKc upper surface of these is attaclied tlie lower portion of 

 the leaves which have been cut off : on the under surface mav he 

 seen a zigzag line of little elevated dot-like rings, the scars of 

 roots. The root-stock is usually rough and shrunken, varying 

 m colour from dark-brown to orange-brown^ breaking easily 

 with a short corky fracture, and exhibiting a whitish spongy 

 interior. The odour is aromatic and agreeable ; the taste 

 bitterish and pungent. The Persian varietj^ of Acorus is 

 darker in colour when fractured and has a more powerful 

 odour, the leaves have been entirely removed, instead of being 

 cut off short. 



Microscojnc sfruefnre. — A section of the rhizome is like an 

 open network composed of rows of nearly round cells and open 

 spaces (water passages) ; most of the cells contain small starch 

 granules, but some of them essential oil ; at the junction of the 

 cortical and central portions of the rhizome is a very distinct 

 row of small empty cells. The vascular bundles are numerous, 

 especially just within the line of small cells just noticed; each 

 bundle consists of a ring of spiral vessels surrounding a number 

 of jointed tubes. 



Chemical com^wsition . — The authors of Pharmacofjrajyh id 

 say :-^ " The dried rhizome yielded us - 1 '3 per cent, of a yel- 

 lowish neutral essential oil of agreeable odour, which in a 

 column of 50 mm. long deviates the ray of polarized light 

 IS'S*^ to the right. By working on a large scale, Messrs. Schira- 

 ^el & Co., of Leipzig, obtained 2-4 to 2-6 per cent. According 



to Kurbatow (1873j, this oil contains a hydrocarbon, C'^H 

 filing at]59*^C., and forming a crystalline compound with 

 fiCl. and another hydrocarbon boiling at 255—258° C, 

 affording no crystallizable hydrochloric compound. By sub- 

 ^itting the oil to fractional distillation, we noticed, above 250% 

 a blue portion, which may be decolourized by sodium. ITie 

 ^nide oil acquires a dark-brownish colour on addition of per- 

 ^tiloride of iron, but is not at all soluble in concentrated potash 



Roluti 



ion. 



^e bitter principle, Acorin^ was isolated by Faust in 1867, 

 ^ semi.fiuid^ brownish glucoside, containing nitrogen, soluble 



