1252

ELEMENTS OF MATERIA MEDICA.

Composition. —Cotton is a modification of lignin, and con ® lS ^ S ’ )r0 poi'fore, of carbon, hydrogen, and oxygen; but the precise relativetions of its constituents have not been ascertained. In all its e ^chemical properties it agrees with ordinary woody fibre. It lS aC jJs-pletely insoluble in water, alcohol, ether, oils, and vegetab e ^ j t _Strong alkaline leys dissolve it. The strong mineral acids decompWith nitric acid it yields oxalic acid. 1 ]jas

Physiological Effects and Uses. —Raw cotton, or cotton-woebeen employed with apparently good effect in the treatment o j a y S(Anderson, Ed. Med. and Surg. Journ. vol. xiii. p. 215, 1828). gU bsti"pain and irritation, apparently by forming, with the discharges, atute for the epidermis, under the protection of which the processformation of the new cuticle takes place, undisturbed by externa t j,etion. The exclusion of the air seems to be a most important partreatment; and, of course, to effect this, many other agents (as m i 0 y-answer in the place of cotton. The following is the method of e ol jghing cotton :—The cotton should be carded in narrow fleeces, thin e t0to be translucent, and applied in successive layers, so as cornp Jtprotect the injured parts from the effects of motion and pressure. pc

the skin is severely scorched, a spirituous or turpentine wash flS e

applied previously to the application of the cotton. As coinpl ete Eof the part is necessary, the first dressing should be allowed to relong as possible undisturbed. peco

Cotton -wool impregnated with nitre or chlorate of potash haemployed asmoxa (see p. 957). . „ fof

The well-known superiority of linen to cotton, as a dress o ^ )Cwounds and ulcers, is usually ascribed to the triangular shapecotton fibres, the sharp angles of which are supposed to cut and ofthe flesh. But this shape of the fibres exists only in the imagin®those who have never examined them by the microscope. to

( Chim. Organ.) ascribes the superiority of linen for surgical puR^j^j tothe hollow condition of the tubular fibrillso, by which they are ena 0 jabsorb into their interior the blood or purulent secretion. The aJj J,cotton, on the other hand, are filled with an organizing substan >therefore, can imbibe nothing into their interior.

Order 72. Lina'ce/E, Lindley .— The Flax Tribe-

LiNEiE, Decandolle .

Essential Character. —Calyx three- or four-, generally five-sepaled. *JJf cle ,rent only at the base, imbricate in (estivation, continuous with the p e e a ttherefore persistent. Petals as many as the sepals ; hypogynous, unguicubase, slightly united together, and to the ring of the stamens; alterna d 1

sepals, twisted in aestivation. Stamens equal in number, and alterna ^,

petals, cohering into a monadelphous ring at the base, and having an a . gubfwment, or tooth, between each. Anthers innate, bilocular, bi-rimose. .asTumer oft,bose, with as many cells as there are sepals, rarely fewer. Styles as n tt>

the cells of the ovary. Capsule globose, crowned by the permanent ® a p C jt lystyles, composed of carpels having induplicate margins and dehiscing at ^ jjesdFtwo valves, and which are divided into two partial cells, by an inconipw ^ i)( , r alfment arising from the centre. Seeds in each cell, two inverted. Alburnen tnone, but in its stead there is a tumid fleshy endopleura. Embryo straig" ’ eS (V- jradicle turned towards the hilum .—Herbs or shrubs with entireexstipulateie 0 jl a* 1

Properties. —The fibres of I.inacese have great tenacity. The seeds abounmucilage, and are in consequence emollient.