498 FORMATION OF ALKALOIDS Chap. XXVlll. 



up by clumps or irregular lines of trees ; and eare must be 

 taken that the supplies of moisture and of water are not 

 prejudiced by too mucli felling. But these details may safely 

 be left to Mr, Mclvor, who now has the assistance of two 

 well-instructed English gardeners, named Batcock and Lyall ; 

 and he will be able to obtain uniform and constant yearly 

 supplies of bark, without any damage to the trees, M^hich, 

 when once full-grown, will thrive luxuriantly, and yield 

 abundance of seeds. 



The most suitable positions for chinchona-plants, as regards 

 elevation and climate, having been pointed out, and the 

 best method of treatment with respect to exposui-e being 

 decided in favour of planting out in open ground, two - other 

 questions remain to be discussed wliich are intimately con- 

 nected with the above, — namely, the conditions under which 

 the largest per-centage of febrifugal alkaloids will be formed 

 in the bark,* and the method of cultivation which is likely to 

 yield the largest and most remunerative supplies of bark in 

 the shortest time. 



One well-established fact, which is proved by universal ex- 

 perience, is that all the species of cliinchona-trees produce the 

 thickest bark and the largest per-centage of alkaloids when 

 growing at the highest elevation at which they respectively 

 flourish. Thus, all other circumstances being favourable, the 

 0. Calisaya and G. succiruhra species will yield more profit- 

 able crops when growing at an elevation of 6000 feet, than 

 at one of 5000 feet. The shrubby varieties of chinchonse are 

 specially good when their stunted growth is owing to the 

 altitude of the locality.^ Mr. Spruce ascertained, with regard 

 to the "red bark," that the greater the height at which the 



* Mr. Howard thinks that the alka- I somewhat less eo in that of the trunk, 

 loida are formed in tlie harks, hy a and most impure in that of the roots, 

 reaction between ammonia and chin- — Microscopic Obserrations, p. 2. 

 cho-tannic acid. The alkaloids are | ■' Howard. 

 pure in tlie bark of the branches, \ 



