RADIX GENTIANJ^. 435 



Microscopic Structure — A transverse section shows the bark 

 separated by a dark cambial zone from the central column ; the radial 

 arrangement of the tissues is only obvious in the latter part. In the 

 bark, liber fibres are wanting ; and in the centre there is no distinct 

 pith. The fibro-vascular bundles are devoid of thick-walled ligneous 

 prosenchyme ; this may explain the consistence, and the short even 

 fracture of the root. It is moreover remarkable on account of the 

 absence both of starch and oxalate of calcium; the cells appear to 

 contain chiefly sugar and a little fat oil. 



Chemical Composition — The bitter taste of gentian is due to a 

 substance called Gentiopicrin or Gentian-hitter, 0*H**0'^ Several 

 chemists, as Heniy, Caventou, Trommsdorff, Leconte and Dulk have 

 described the bitter principle of gentian in an impure state, under the 

 name of Gentianin, but Kromayer in 1862 first obtained it in a state 

 of purity. Gentiopicrin is a neutral body crystallizing in colourless 

 needles, which readily dissolve in water. It is soluble in spirit of wine, 

 but in absolute alcohol only when aided by heat; it does not dissolve 

 in ether. A solution of caustic potash or soda forms with it a yellow 

 solution. Under the influence of a dilute mineral acid, gentiopicrin is 

 resolved into glucose, and an amorphous, yellowish-brown, neutral sub- 

 stance, named Gentiogenin. Fresh gentian roots yield somewhat more 

 than yV psr cent, of gentiopicrin ; from the dried root it could not be 

 obtained in a crystallized state. The medicinal Tincture of Gentian, 

 mixed with solution of caustic potash, loses its bitterness in a few days, 

 probably in consequence of the destruction of the gentiopicrin. 



Another constituent of gentian root is Gentianin or gentimn 



(CW 

 Ci^HioQs or (OH)2C6H3 CO.C6H2 ■< O^. It forms tasteless yeUowish 



prisms, sparingly soluble in alcohol, requiring about 5000 parts of 

 water for solution. With alkalis it yields intensely yellow crystalliz- 

 able compounds, which, however, are easily decomposed already by 

 carbonic acid. Gentianin may be sublimed if carefully heated at 250° C. 

 By melting it with caustic potash, acetic acid, phloroglucin, 

 O'W{0Wf, and oxysalicyHc acid, C^W{OnyGOO^, are produced, as 

 shown in 1875 by Hlasiwetz and Habermann. The name of gentianic 

 acid or gentisinic acid had been applied to the oxysalicylic acid obtained 

 by the above decomposition before it was identified with oxysalicylic 

 acid from other sources. 



Gentian root abounds in pectin ; it also contains, to the extent of 12 

 to 15 per cent., an uncrystallizable sugar, of which advantage is taken 

 in Southern Bavaria and Switzerland for the manufacture by fermenta- 

 tion and distillation of a potable spirit.^ This use of gentian and its 

 consumption in medicine have led to the plant being almost extirpated 

 in some parts of Switzerland where it formerly abounded. 



The experiments of Maisch (1876) and Ville (1877) have shown 

 tannic matters to be absent from the root. 



Commerce — Gentian root finds its way into English commerce 

 through the German hoiLses ; and some is shipped from Marseilles. The 

 quantity imported into the United Kingom in 1870 was 1100 cwt. 



»Th. Martins, Pharm. Journ. xiL (1853) 371. 



