A companion to the United States pharmacopia; . s,falling off or remainingadherent as dead very frequently oc-curs in barks of conifers,cinchonas, etc., and whenit does occur it is oftendifficult to understand thestructure of the bark, which may appear to be -, Fig. 650.—Cotton-root Bark, very irregular. Our illustration of dogwood bark (Fig. 653) shows us such a barkin which secondary cork (s, s, s) separates two layers from each other, the inner (a) being theliving inner bark with med-ullary rays (m, m) and theouter being dead tissue. In some works of botanythe sequestered portio
A companion to the United States pharmacopia; . s,falling off or remainingadherent as dead very frequently oc-curs in barks of conifers,cinchonas, etc., and whenit does occur it is oftendifficult to understand thestructure of the bark, which may appear to be -, Fig. 650.—Cotton-root Bark, very irregular. Our illustration of dogwood bark (Fig. 653) shows us such a barkin which secondary cork (s, s, s) separates two layers from each other, the inner (a) being theliving inner bark with med-ullary rays (m, m) and theouter being dead tissue. In some works of botanythe sequestered portion iscalled bark (borke, G.), butit is not the bark in a phar-mocognostic sense. It is plain that the struc-ture we have described hereas a true bark can onlyoccur in plants with exoge-nous growth and never inendogenous stems or are usually largeflattened organs designedto expose a large surfaceto the air for respiration. For the purposes of study the pharmacog-nocist may divide them into two classes—the leathery or coriaceous,. Pig. 651. -Transverse Section of Bast of Old CalisayaBark. 1102 A COMPANION TO THE and the herbaceous, which differ in the rigidity of their structures, theleathery having more lignified fibro-vascular bundles and tougher epi-dermis, so that they retain their shapes on drying, as senna or eucalyp-tus ; while the herbaceoushave delicate fibro-vascularbundles, soft parenchyma,and thin epidermis, andshrink and crumple on dry-ing, as in digitalis. The blade of the leafconsists of a network offibro-vascular bundles, whichis a framework on whichthe leaf is expanded andsupported, and which iscalled the skeleton of theleaf. Leaf-skeletons may beprepared by taking leatheryleaves and placing them inrain (soft) water with a littleyeast, and after some timetaking them out and laying on a plate, when the epidermis and pulphave been so softened that they may be washed out with a stream ofwater from a spritz-flask, or by gently beating with a soft brus
Size: 1581px × 1581px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishernewyo, bookyear1884
