. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. At one or several places, the formative layer is thickened to the so-called nucleus, (a fig. 2) the point from which growth and transformations proceed. Within the cell thus constructed exists a liquid, the cell-contents, from which, in course of time, solid cell contents of various character are found todevelope. In a chemical sense, not less than in a structural, the single globu- lar cell is the type of all vegetation. The outer wall of
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. At one or several places, the formative layer is thickened to the so-called nucleus, (a fig. 2) the point from which growth and transformations proceed. Within the cell thus constructed exists a liquid, the cell-contents, from which, in course of time, solid cell contents of various character are found todevelope. In a chemical sense, not less than in a structural, the single globu- lar cell is the type of all vegetation. The outer wall of the cell is formed of that material which is itself the most abundant product of vegetable life, and which rep- resents an important group of bodies, that are familiar to all, as large ingredients of our daily food. The table wdiich here follows gives the names and the chemical formulae of what we may term the cellulose group or the vegetal CARBO-HYDRATES. ^12 c12 c 12 H, , (\ H, 0, 0, Cellulose Starch Inulin Dextrin Gum Cane sugar Fruit sugar Grape sugar Cellulose is the body already alluded to as constituting the material of the outer coating of the cells. It often accumulates in some parts of the plant by the thickening of the cell walls, thus forming the greater share of the wood (fig. 4) of trees and shrubs. Linen,hemp,() and cotton (Afig. 3)are nearly or quite pure cellulose. It exists largely in the stones or shells of r^ fruits and nuts. The so-called vege- \ | \ table ivory is chiefly a very compact form of cellulose. In general, this proximate organic element is the frame-work of the plant, and the material that gives toughness and solidity to its parts. Cellulose is characterized by its great indifference to most ordinary solvents. Water, alcohol, &c, do not dissolve it, and the stronger rea- gents of the chemist rarely take it up without occasioning essential changes in its constitution.* With strong nitric acid it yields nitre-eel-. s'According to Pelouze
Size: 1286px × 1943px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsmithsonianinstitutio, bookcentury1800, bookdecade1840
