36 Present State of the Genus Cinchona. 
Pharmaceutic requisitions, and thus to discriminate between 
forms which, in a therapeutic point of view, produce wholly 
different products, and which have been thrown together 
by systematic arrangement founded on insufficient data. 
The C. micrantha of Huanuco, for instance, produces a 
“grey bark,” characterised by its abundant yield of pure 
cinchonine ; whilst the C. micrantha of Bolivia differs 
_widely in its chemical contents, and presents apparently 
a somewhat differing form. Again, the C. ovata of Pavon 
and of Peru, gives an entirely worthless bark producing 
aricine (or paracin), whilst the C. ovata, var. rujfinervts, 
Wedd., of Bolivia, is a plant allied to the Calisaya in its 
products, and the C. ovata, var. erythroderma, approaches 
to, and is not*improbably found amongst the red-bark-pro- 
ducing plants. . 
Mr. Howard does not propose to found a diagnosis of 
species, either on the chemical constituents of the barks, or 
on their microscopical constitution, but to follow out more 
fully, and to a greater extent, the consideration of the barks 
as assisting in the discrimination of species and varieties, 
according to the precedent so ably established by Dr. 
Weddell in his admirable “ Histoire des Quinquinas.” 
Mr. Howard is nearly in accordance with Dr. Weddell 
and with M. Gustave Planchon (whose recently published 
work* he regards as the most valuable manua/ that has yet 
appeared on the subject), in regarding “ cinchona as form- 
ing a very natural genus, the different forms of which often 
pass from one into another by insensible transitions,’ but 
leaving it open for further investigation whether there may 
not, as stated by Dr. Karsten, be a subgenus, forming a 
point of transition between Czuchona and Ladenbergia. 
However this point may be decided by botanists, the 
writer thinks that a considerable section of the Czuchone 
are allied in their chemical and also in their microscopical 
characteristics to the Ladenbergig, whilst, on the other 
hand, some of the latter seem to reciprocate this alliance. 
The writer does not, however, regard the “transitions” 
as insensible, but rather as by well-marked and permanent 
intermediate forms: he looks upon the Ciuchone not as he 
would upon the Salices, for instance, in which latter family 
it seems immaterial how many or how few are the number 
of species or varieties recognised, since a willow is still the 
* “Des Quinquinas,” par Gustave Planchon; Savy, Paris, 
1864. 
