A companion to the United States pharmacopia; . r moisture andshrink, while the outer cellsretain their shape. This gen-erally causes the bark to curlinward, and according to thedegree of curvature different Fig. Section of Fernambuco Wood. names are given to the barks. When the curvature is slight, as in Fig. 643 «, the pieces are usuallydescribed as curved pieces, but as curvature may take place in anirregular manner, we preferto restrict the term curvedpieces to pieces of bark ofsuch irregular shape, andpropose the term troughs as a more convenient, ex-pressive, and appropri
A companion to the United States pharmacopia; . r moisture andshrink, while the outer cellsretain their shape. This gen-erally causes the bark to curlinward, and according to thedegree of curvature different Fig. Section of Fernambuco Wood. names are given to the barks. When the curvature is slight, as in Fig. 643 «, the pieces are usuallydescribed as curved pieces, but as curvature may take place in anirregular manner, we preferto restrict the term curvedpieces to pieces of bark ofsuch irregular shape, andpropose the term troughs as a more convenient, ex-pressive, and appropriateword to describe the piecesof bark curved as in thedrawing. If the bark isrolled from one side com-pletely into a cylinder thisis termed a quill, or a simplequill (Z>), while if it is rolledinward from both sides (c),it is called a double quill. An unequal shrinking ofbast and medullary rays willcause longitudinal wrinkles, or, if the external layers will not yieldreadily, so as to form quills on drying, fissures on the inner surface of. Fig. 641. -Radial Section of Logwood, showingMedullary Ray. UNITED STATES PHAKMACOPOEIA. 1099 the bark, as in wild cherry bark(Fig. 646), or ridges as in alnusrubra (Figs. 647, 648). Occasionally the middle barkshrinks in drugs which are coveredonly with a thin layer of suber orepidermis, while the bast-cells arerigid and the bast-parenchyma alsomore or less unyielding, or perhapsbits of wood are attached on theinner surface when the bark ischipped off instead of being peeledoff, and in such a case it is possible that the upper and lower ends ofthe bark curve outward, producing longitudinal curvature. We occa-
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishernewyo, bookyear1884
