362 RUBIACEJE. 



corymhosa Karst., 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 

 S^ to 4|^ per cent, of sulphate of quinine. 



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

 tion of quills of C. officinalis 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. 

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

 quinine was predominant. In Java too. Cinchona Ledgeriana (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 

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

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

 to 6 per cent, of quinine. 



As to Crown or Loxa Bark, the Cortex Ginchonce palUdce of phar- 

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

 introduction in the 17th century, when it was taken from the trunks 

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

 medicinal bark ; but the same cannot be said of much of that now 

 found in commerce, which is to a large extent collected from very 

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

 of extraordinary excellence, as shown by the recent experiments of 

 De Vry.'' 



As to Red Bark, the thick flat sort contains only 3 to 4 per cent, of 

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

 fourth cinchonidine, the remainder being cinchonine and sometimes 

 also traces of quinidine (conquinine). 



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

 total percentage, but also to the proportion which one bears to another. 

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

 dine 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 



'^Die medicinischen Chinarinden Neu- * See Howard's analyses and observa- 



Granada's, 17. 20. 39. tions, Pharm. Journ. xiv. (1855) 61-63. 



^Pharrn, Journ. Sept. 6, 1873. 181. » Pharm. Journ. Sept. 6, 1873. 184. 



3 Blue Book — " Hast India Chinchana « Blue Book, 1870. 116. 188. 205. 

 Plant," 1870. 282; Yearbook of Pharmacy, 

 1871. 85. 



