Naturalisation in Extra-Tropical Countries. 125 



nearly coinciding with that of the Assam-tea. Cross found the 

 temperature of some of the best natural Cinchona-regions to fluctuate 

 between 35 and 60 F. We here ought to consociate the Peru-bark 

 plants with naturally growing fern-trees, but only in the warmest 

 valleys and richest soil. The best temperature for Cinchonas is from 

 53 to 66 F. ; but for the most part they will endure in open places 

 a minimum of 32 F.; in the brush-shades of the Botanic Garden of 

 Melbourne, where already many years ago Cinchonas were raised by 

 the thousands, they have even resisted 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 F. 



The plants are most easily raised from seed, best under some cover 

 such as mats ; they produce seeds copiously some years after planting. 

 C. succirubra, first introduced into California by the writer of this 

 work together with the principal other species, thrives well in the 

 lower coast-ranges as far north as San Francisco ; better indeed than 

 C. Calisaya, according to Dr. Herman Behr. The quantity of alka- 

 loids in the bark can be much increased by artificial treatment, if the 

 bark is only removed to about one-third on one side of the stem and 

 the denuded part covered with moss or straw-matting (kept moist), 

 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 25 per cent, alkaloids, because no loss of 

 these precious substances takes place by gradual disintegration 

 through age. The root-bark of some Cinchonas has proved to contain 

 as much as 8 per cent, of alkaloids (see Gardeners' Chronicle, 1877, 

 p. 212). The income from Java-plantations is considerably over 

 double the cost of the expenses of culture and transit. Mr. Howard's 

 opinion, that Cinchonas in lowland-plantations produce a far less 

 quantity of alkaloids, needs further confirmation, particularly regard- 

 ing the valuable quinin and cinchonidin ; probably however geologic 

 conditions have in all instances to be taken into account also. 



Young Cinchona-plants are set out at distances 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 Ib. according to quality. The 

 limits assigned to this literary compilation do not admit of entering 

 further into details on this occasion ; but I may add, that in the 

 Darjeeling-district over three millions of Cinchona-plants were already 

 in cultivation during 1869 in Government-plantations. Cultivation 

 of Cinchona for commercial purposes was first initiated in Java 

 through Dr. Hasskarl in 1851 at the suggestion and under the 

 direction of Professor Miquel ; but 240,000 Ibs. of bark were already 

 exported from this island in 1880. The British harvest in the 

 Madras-Presidency alone amounted to 150,000 Ibs. in 1875. Brigade- 

 Surgeon Dr. G. King reports in 1880, that four million trees of 

 Cinchona succirubra are now under his control in the Sikkim-planta- 

 tions. This has proved the hardiest species ; it grows under a wide 

 range of conditions and seeds freely ; thus it is the most valuable 



