38 Present State of the Genus Crnchona. 
order in which in the plants themselves these alkaloids are 
produced, normally in concert, and under circumstances of 
changed locality are supplemented, or even superseded by 
each other. Thus the quinine-producing calisaya forms 
always some, and abnormally much cinchonidine, and cin- 
chonine-producing C. micrantha of Peru forms in India a 
large product of quinidine. 
Mr. Howard thinks the species of calisaya can be best 
studied in connection with the different geographical 
centres, the products of which he proposes briefly to review, 
so far at least as concerns their most prominent species, 
beginning with Bolivia. 
The Barks of Bolivia. 
Cinchona calisaya, Weddell.—This species certainly merits 
the first mention. It is beyond all question the first in im- 
portance in commerce, as furnishing the bark most largely 
used in the production of the precious medicine quinine. 
It contains this product in remarkable purity, with very 
little admixture of any other alkaloid—a fractional quantity 
of cinchonidine and cinchonine being (in the best speci- 
mens) the only exception. 
It is not to be supposed that the products of wild forests 
should be kept carefully select in commerce, and conse- 
quently the rate of produce in alkaloid, from such mixed 
parcels of bark, falls below that of the genuine tree; but 
Mr. Howard has satisfied himself, by the examination of 
carefully-chosen specimens of calisaya, of the existence of 
alkaloid equal to 5 per cent., and in one or two specimens 
even seven or eight parts in a hundred of sulphate of 
quinine. This is more than double the product assigned 
by the late M. Delondre, whose “ Quinologie” he regards 
asa very valuable repository of knowledge, although (as 
is always the case) subject to some little correction. 
The average produce of calisaya bark in quinine,* though 
falling very far short of the exceptionally fine specimens 
before mentioned, is still considerably above that obtained 
by M. Delondre, and the product in cinchonine less by two- 
thirds than he states, only it may be that he includes the 
cinchonidine in the same category. These observations 
seem of importance in reference to the cultivation of the 
species in India. It must not be supposed that the large 
* Not contained in the bark as szdphate, as Delondre and Bou- 
chardat’s work might lead the reader to suppose. 
