260 MATERIA MEDIC A AND THERAPEUTICS. 



inches to two feet, from one to three inches wide, and two to 

 six lines thick, compact and heavy; outer surface brown or 

 reddish-brown, rarely white from adherent lichens, rugged or 

 wrinkled longitudinally, frequently warty, and crossed by deep 

 transverse cracks ; inner surface redder ; fractured surface often 

 approaching to brick-red ; transverse fracture finely fibrous ; 

 powder red-brown ; taste bitter and astringent. 



1 11 eh on a L.ancifoliae Cortex LANCE- 

 LEAVED CINCHONA BARK. The bark of Cinchona 

 lancifolia, Mutis. Spongy or orange Carthagena 

 bark. 



Characters. Either in quills of various size with brownish 

 epidermis, and whitish crustaceous and foliaceous lichens, 

 extremely fibrous, moderately bitter ; or as curved pieces, of an 

 orange or red colour, with an extremely fibrous liber, of stringy 

 fracture, very slightly bitter. 



Composition. Cinchona bark contains (1) four alkaloids, 

 namely : quinia, cinchonia, quinidia, and cinchonidia ; (2) two 

 peculiar acids : kinic and kinovic acids ; (3) a variety of tannic 

 acid, called cincho-tannic acid; (4) cinchona red; and (5) an 

 aromatic volatile oil. 



1. The alkaloids of cinchona. a. Quinia, C 2o H 24 N 2 2 , 

 occurs (as the hydrate) in white acicular crystals, inodorous, 

 very bitter ; reacting like an alkali, and forming neutral and 

 acid salts with acids ; presenting fluorescence in dilute solutions 

 of the sulphate ; and turning the plane of polarisation to the 

 left. An amorphous form of quinia is found after crystallisation 

 of the sulphate from the mother-liquors, and from quinoidia, 

 which appears to be a compound of the alkaloids with resin and 

 colouring matters. 



b. Cinchonia. C 20 H 24 N 2 0, consists of colourless prisms, 

 inodorous, and bitter ; f orms salts with acids ; but possesses no 

 fluorescence in solution ; and deflects the plane of polarisation to 

 the right. 



c. Quinidia^ C 2o H 24 N 2 02, i.e. isomeric with quinia, closely 

 resembles quinia, but crystallises in prisms, and deflects the 

 plane of polarisation to the right. 



d. Cinchonidia. C 2() H 24 N 2 0, i.e. isomeric with cinchonia, 

 resembles that alkaloid, but yields fluorescent solutions, and 

 left-handed polarisation. 



As a rule quinia is most abiindant in yellow bark, cinchonia 

 in pale bark, and the red bark contains a considerable pro- 

 portion of each. Quinidia is specially abundant in the bai'l: 

 of lancifolia. More exactly, yellow bark yields 2'5 to 3'8 per 



