362 RUBIACE.E. 



corymhosa Ktirst., and C. lancifolia Mutis, are due to Karsten. He 

 ascertained^ that barks of one district were sometimes devoid of quinine, 



while those of the same species from a neighbouring locality yielded 

 3| to 4| per cent, of sulphate of quinine. 



Another striking example is furnished by De Vry^ in his examina- 

 tion of quills of C. ojfficmoMs grown at Ootacamund, which he found to 

 vary in percentage of alkaloids, from 11"96 (of which 9'1 per cent, was 

 quinine) down to less than 1 per cent. An extremely remarkable 

 variation has also been displayed, as already alluded to at p. 351, by 

 Ledger's Calisaya. 



Among the innumerable published analyses of cinchona bark, there 

 are a great number showing but a very small percentage of the useful 

 principles, of which quinine, the most valuable of all, is not seldom 

 altogether wanting. The highest yield on the other hand hitherto 

 observed, was obtained by Broughton^ from a bark grown at Ootacamund. 

 Thisbark afforded not less than 13| per cent, of alkaloids, among which 

 quinine was predominant. In Java too, Cinchona Ledgcriana (see 

 pp. 341, 351) has proved since to afford much more alkaloid than any 

 American barks; as much as 13-25 per cent, of quinine have been 

 observed in its bark. 



The few facts just mentioned show that it is impossible to state 

 even approximately any constant percentage of alkaloids in any given 

 hark. We may however say that good Flat Calisaya Bark, as offered 

 m the drug trade for pharmaceutical preparations, contains at least 5 

 to 6 per cent, of quinine. 



As to Crown or Loxa Barh, the Cortex Cinchonce iMllklai of phar- 

 inacy, its merits are, to say the least, very uncertain. On its first 

 mtroduction in the 17th century, when it was taken from the tninks 

 and large branches of full-grown trees, it was doubtless an exceUent 

 medicmal bark ; but the same cannot be said of much of that noAV 

 found m commerce, which is to a larfre extent collected from very- 



young wood.* Some of the Crown Bark produced in India is however 

 ot extraordinary excellence, as shown by the recent experiments ot 

 De Vry."^ "^ 



As to Red Baric, the thick fiat sort contains only 3 to 4 per cent, of 

 alkaloids, but a large amount of colouring matter. The quill Ked Bark 

 of the Indian plantations is a much better drug, some of it yielding 5 

 to 10 per cent, of alkaloids, less than a third of which is quinine and a 

 tourth cmchonidme, the remainder being cinchonine and sometimes 

 also traces of quinidine (conquinine). 



fc> 



The variations in the amount of alkaloids relates not merely to their 

 t()tal percentage, but also to the proportion which one bears to another. 

 Yumine and cinchonine are of the most frequent occurrence ; cinchoni- 

 clme IS less usual, while quinidine is still less frequently met with and 

 never in large amount. The experiments performed in India« have 

 already shown that external influences contribute in an important 



GVWart?""i?^\t ^'"■"'''•"'^^'» -^^^"- ^See Howard's analyses and f^f^" 



'-Pharn Jo,,rl' 'i , o ic-„ *ions, Pharm. Journ. xiv. (l85o) 61-b^- 

 ' Blue Book "7*; ^) ^^.'^- ^^^- ' ^/'«'™- Journ. Sept. 6, 1873. 184. 



'««^" 1S7S?287- rZlthTf p7"""^''^«« ' Bl^e Book, 1870. 116. 188. 20o. 



71.85. ' -^ '^^^ ('OOK oj narmaci/, 



Plant 

 18 



