264 



BARKS 



The colour of the inner surface is usually yellowish brown, and the 

 taste resembles that of calisaya bark in being bitter as well as astringent. 

 4. C. succirubra. This species yields a drug that is characterised 

 by a more or less distinct reddish colour, and is therefore usually 

 known as ' red bark ' ; it occurs in two forms, viz. ' flat ' and ' quill.' 

 The former is occasionally imported from South 

 America ; the latter is obtained from cultivated 

 trees, and is imported principally from Java. 



(a) Flat red bark occurs in flattish pieces, often 

 of considerable size, and attaining 20 mm. in 

 thickness, though usually thinner ; in these respects 

 it resembles flat calisaya, but it differs from that 

 bark essentially in having the outer bark attached ; 

 the latter is rugged, of a dusky, ferruginous red 

 colour, and marked with longitudinal ridges of cork 

 as well as brighter red warts. The inner surface 

 has also a distinctly red colour, and does not exhibit 

 the wavy fibrous structure characteristic of flat 

 calisaya. 



The bark has a bitter and markedly astringent taste. 



(b) Quill red bark. The only official cinchona 

 bark is that obtained from the stem and branches 

 of cultivated plants of C. succirubra. The quills 

 vary in size, but are often about 25 mm. in 

 diameter. The outer surface is of a dull brownish 

 grey or reddish brown colour, and often bears 

 numerous greyish lichens attached to it. It is 

 always more or less strongly wrinkled longitudinally, 

 and marked with warts which are sometimes small 

 and numerous or sometimes larger and scattered ; 

 in the latter case they are usually either reddish in 

 colour or exhibit a reddish colour when broken. 

 Some varieties of the bark bear small transverse 

 cracks and reddish warts, the longitudinal wrinkles 

 being less pronounced. In thickness the bark varies 

 from 2 to 4 mm. The colour of the inner surface 

 is in typical specimens reddish brown, but that of 



the interior of the bark is yellowish brown. This colour is due to a 

 change in the tannin of the bark, by which a reddish phlobaphene 

 is produced. The bark has a distinctly astringent and bitter taste. 

 The Pharmacopoeia requires that it shall yield between 5 and 6 per 

 cent, of total alkaloid, of which not less than half should consist of 

 quinine and cinchonidine. 



Branch bark may generally be distinguished from trunk bark by 

 being thinner, by bearing more numerous wrinkles and small warts, 

 and by being more strongly inr oiled. 



FIG. 133. Pale 

 bark (C. offici- 

 nalis), showing 

 very numerous 

 longitudinal 

 and transverse 

 cracks. Large 

 specimen, nat- 

 ural size. 



