EUCALYPTUS TREES. 283 
ed uninjured a temperature of a few degrees less, 
wherever the wind had no access, while under such 
very slight cover the Cinchonas withstood also a heat 
of a few degrees over 100 degrees F. The plants are 
most easily raised from seeds, best under some cover, 
such as mats, and they are seeding copiously already 
several years after planting. The contents of alka- 
loids in the bark can be much increased by artificial 
treatment, if the bark is only removed on one side of 
the stem and the denuded part covered with moss, 
under which in one year as much bark is formed as 
otherwise requires three years’ growth, such forced 
bark moreover containing the astounding quantity of 
as much as 25 alkaloids, because no loss of these pre- 
cious substances takes place by gradual disintegration 
through age. The Cinchona-plants are set out at dis- 
tances of about 6 feet. The harvest of bark begins in 
the fourth or fifth year. The price varies in Europe 
from 2s. to 9s. per lb., according to quality. The lim- 
its assigned to this small literary compilation do not 
admit of entering further into details on this occasion, 
but I may yet add, that in the Darjeeling district over 
three millions of Cinchona-plants were in cultivation 
in 1869, raised in government plantations. 
Citrus Aurantium, L.*—The Orange (in the widest 
sense of the word). A native of South Asia. A tree 
of longevity, known to have attained an age of 600 
years and more. Any specific differences, to distin- 
guish C. aurantium from C. medica, if they once ex- 
isted, are obliterated now through hybridization, at 
least in the cultivated forms. As prominent varieties 
of C. aurantium may be distinguished : 
Citrus Bigaradia, Duhamel,—The Bitter Orange, 
