MYRTACE. al 
7 conserve are astringent and suitable to those suffering from 
_ diarrhoea and dysentery. (Corre et Lejanne, Résumé de la Mat. 
_ Med. Coloniale, p. 108.) 
_ Description.—The external surface of the bark when 
_ fresh is smooth and brown, marked by superficial scars indica- 
ting the separation of squamous plates of dead bark. These 
_ plates sometimes remain partially attached. Beneath the 
_ brown epidermis the fresh bark is green; its inner surface 
_ is marked by longitudinal striz, and is of a light brown colour. 
_ The taste is astringent and agreeably acid. The leaves are 
aromatic, egg-shaped or oblong, short stalked, covered with 
_ soft down underneath, and with the principal veins very 
_ prominent. 
Microscopic structure.—Sections show that the bark consists 
_ of an epidermis, made up of two rows of brick-shaped brown 
4 cells, and alternate zones of vascular and parenchymatous 
_ tissue, varied towards the inner part by three broken circles 
of liber cells. The medullary rays are numerous, and together 
_ with the parenchyma of the outer part of the bark, loaded with 
green colouring matter; in the rays this extends some distance 
to its substance, and makes them very conspicuous. The 
scular system is loaded with crystals, and contains a few 
arch granules. 
Chemical composition.—The watery extract of the bark con- 
4 tains, as the mean of two determinations, 27:4 per cent. of 
tannin, Spirit dissolves the same amount of extract from it 
as water, about 33 per cent. The tannin gives a blue-black 
_ colour with ferric salts, a pinkish precipitate with gelatine, and 
a dirty green with acetate of lead; the lead compound when 
_ perfectly dry yields 29 per cent. of oxide. 
_ After exhausting the bark by means of water and alcohol, 
_ another colouring matter is removed by soda, probably oxidized 
tannin. Ether extracts chlorophyll, and a little resin soluble 
_ ammonia are present. The mineral-matter obtained by i 
ion is 10 per cent., and consists of calcium ¢ 
_ with a bright red colour in alkaline liquids. No alkaloids ¢ OB: a 
