I 



364 RUBIACE^. 



occurs in cinchona barks, and has been met with by Rembold (1868) 

 in the rhizome of Potentilla Tovmentilla Sibth. 



Other Constituents of Cinchona Barks — Quinovic acid is ac- 

 companied by Quinovin (or Chinovin), C^"H^'^0^ an amorphous bitter 

 substance, first obtained (1821) by Pelletier and Caventou under the 



name of Kinovic Acid, from China nova^ in which it occurs combined 

 with lime. Quinovin in alcoholic solution was shown in 1859 by 

 Hlasiwetz to be resolved by means of hydrochloric gas into quinovic 

 acid, C^^ff'^O^ and an uncrystallizable sugar, Mannitan, C^ff^O^ with 

 subtraction of ffO. The formation of quinovic acid takes place more 

 easily, if quinovin is placed in contact with sodium amalgam and spirit 

 of wine, when, after 12 hours, mannitan and quinovate of sodium are 

 formed (Rochleder, 1867). 



Quinovin, although an indifferent substance, may be removed from 

 cinchona barks by weak caustic soda, from which it is precipitable by 

 hydrochloric acid, together with quinovic acid and cinchona-red. Milk 

 of lime then dissolves quinovin and quinovic acid, but not tbe red 

 substance. Quinovic acid and quinovin again precipitated by an acid, 

 may be separated by chloroform in which the latter only is soluble, or 

 also by cold dilute alcohol sp. gr. about 0-026, quinovin being readily 

 removed by this liquid. 



^ Quinovin dissolves in boiling water; its solutions, as well as those of 

 qumovic acid, are dextrogyre. Quinovin seems to be a constituent of 

 aJniost every part of the cinchonas and the allied Ginchonem, although 

 tJie amount of it in barks does not apparently exceed 2 per cent. It f 

 accompanied by quinovic acid : both substances are stated to have tonic 

 properties. 



^ Cinchona-red, an amorphous substance to which the red hue of 

 cinchona barks is due, is produced as shown by RemJ^old (1867), when 

 cmcho-tannic acid is boiled with dilute sulphuric acid, sugar being 

 termed at the same time. By fusing cinchona-red with potash, proto- 

 catechuic acid, C'H^OS is produced. Cinchona-red is sparingly soluble 

 in alcohol abundantly in alkaline solutions, but neither in water nor in 

 ether. Ihick Red Bark in which it is abundant, affords it to the extent 

 of over 10 per cent. 



The Cinchona barks yield but a scanty percentage of ash, not 

 exceedmg 3 per cent, a fact well accordincr with the small amount they 

 contain of oxalate and kinate of calcium. 



>v,-ii^^*'m^^'°" of the Alkaloids in Cinchona Bark—The microscope 

 1 1 '}% "'' ^^ ^^^'^a^y shown, to ascertain whether a given bark 

 s derived from Cinchona, but it can furnish no exact information as to 

 the actual value of such bark a,s a drug. 



^ll..i -V ""^f a very simple test by which the presence of a cinchona- 

 alkaloid may bo demonstrated.^ These alkaloids heated in a glass tube 



in the presence of a volatile acid or of substances capable of producing 

 as mentionpTl' ?J°^^° ^'"^^ ^'-^P^^^^ °f '-^ beautiful crimson colour, 



mentioned p. 363. 



a tree wSr^l-S flT"-^"'^'^? ^^ ^^^^ f^^^^- I*^ ^^^^k is destitute of aka o^ « 



cent foHage fiJSlf i^^^"" ^H^ ™*g°ifi- i* also use.l to appear occasionally uitw 



QmnologtofPavon '' afp""^'?^ " ^'"^^''^ ^^''^^^ ^^^^et since about the yea J-O- 



J J i-avoH as Cmchona magni- -See also our article on Cortex Cuscai im 



