[515] See also Weddell's Histoire Naturelle des Quinquinas, p. 32.
[516] Mr. Howard thinks that the alkaloids are formed in the barks, by a reaction between ammonia and chincho-tannic acid. The alkaloids are pure in the bark of the branches, somewhat less so in that of the trunk, and most impure in that of the roots.—Microscopic Observations, p. 2.
[517] Howard.
[518] Spruce's Report, p. 83.
[519] Ibid., p. 27. See also Karsten, p. 20.
[520] Karsten, p. 20.
[521] Spruce's Report, p. 23.
[522] Lindley's Theory and Practice of Horticulture, p. 70.
[523] In quills from large branches there is more alkaloid than in the smaller branches: in the bark of the trunk the proportion is still further increased, but this diminishes in quantity and deteriorates in quality in the bark of the roots.—Howard.
[524] Mr. McIvor reports the thickness of the bark of some of the young plants at Ootacamund to be nearly a quarter of an inch. The bark of quills of C. Calisaya given me by Mr. Howard, as samples from a lot on sale, is only one-eighth of an inch in thickness.