REPORT ON THE CHINCHONA SUCCIRUBRA. 213 
centage would be attained in the East Indies, if time were allowed for 
the growth. 2 
The exact period at which it would be advisable to cut the bark 
must be ascertained by experiment, but I think this should take place . 
as soon as the bark attains to a thickness which would repay the cul- 
tivation. There would be positive disadvantage in allowing the bark 
to attain such an age as is indicated by many of the specimens from 
South America, if the object to be attained is the extraction of the alka- 
loids ; since there is a continual process of deterioration* of these after 
a certain period of the history of the bark, which is connected with the 
oxidation of the red colouring-matter, and the production, in very old 
trees, of. those fine descriptions of bright red bark which command in- 
deed a high price in the market (as much at the present time as eight 
shillings per pound), but which would not, in many cases, be more va- 
luable for the production of Quinine than bark of one year’s growth. 
I next examined the younger bark of one year’s growth, taking care 
to select the most mature portion, and found that it yielded 2°59 of 
alkaloid, of which 2°55 (soluble in ether) appeared to be Quinine and 
Chinchonidine, and in part crystallized into tolerably white sulphate, 
which showed perhaps a rather larger proportion of Chinchonidine than 
in the older bark. On the other hand, the proportion of Chinchonine 
seemed notably less, viz. only 0°04 per cent., but it is possible that the 
separation was not exactly effected between the Chinchonine and Chin- 
chonidine, which is not easily accomplished by ether in such small 
portions. 
The above result induced me to pay further attention to the leaves, 
concerning which the absence of any carmine sublimate by heat led me 
at first to an unfavourable conclusion. The decoctions and infusions 
made by Mr. M‘Ivor, though in perfectly good condition, showed that 
the contents changed most rapidly under the influence of the oxygen 
of the atmosphere as soon as ammonia was added to the, at first, de- 
cidedly acid liquor. Fortunately, a good supply of several ounces of 
dried leaves had been sent over, and from these I succeeded in obtain- 
ing Quinine, though in very small quantity, but presenting its usual 
characteristics, dissolving in acids and precipitated by alkalies as a 
whitish hydrate, soluble in ether, and left by this on evaporation as a 
* Described in my ‘ Illustrations of Nueva Quinologia,’ under head “ C. succi- 
rubra,” P. 14. 
