Copy 1, Volume 1

Elements of anatomy / by James Quain ; Edited by Richard Quain and William Sharpey.

  • Jones Quain
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: Elements of anatomy / by James Quain ; Edited by Richard Quain and William Sharpey. Source: Wellcome Collection.

    40/978
    S Production Resem- blance of the process in animal and vege- tables, x] FORMATION OF THE ANIMAL TEXTURES. go on till the cavity of the cell is nearly or completely filled up (fig. 4°). It is in this way that the woody fibre and other hard tissues of the plant are formed. It farther appears that the particles of each layer are disposed in lines, running spirally round the cell. In place of forming a continuous layer, these secondary deposits may leave little spots of the cell-wall uncovered, or less thickly covered, and thus give rise to what is named pitted tissue (fig. 2,°) ; or they may assume the form of a slender fibre or band, single, double, or multiple, running in a spiral manner along the inside of the cavity, or forming a series of separate rings or hoops, as in spiral and annular vessels (fig. 2°,7). New matter may be absorbed or imbibed into the cells; or a portion of their altered and elaborated contents may escape as a secretion, either by transudation through the cell-wall, or by rupture or absorption of the membrane. Lastly, in certain circumstances, cells may be wholly or partially removed by absorption of their sub- stance. 5. Cells may produce or generate new cells. ‘The mode in which this takes place will be immediately considered, in speak- ing of the origin of animal cells. FORMATION OF THE ANIMAL TEXTURES. Passing now to the development of the animal tissues, it may first be remarked generally, that in some instances the pro- cess exhibits an obvious analogy with that which takes place in vegetables ; certain of the animal tissues, in their earlier condi- tions, appearing in form of a congeries of cells almost entirely resembling the vegetable cells, and, in their subsequent transfor- mations, passing through a series of changes in many respects parallel to some of those which occur in the progress of vege- table development. Cartilage affords a good example of this. Figures 5’ and 6’, a, are magnified representations of cartilage in its early condition ; and whoever compares them with the ap- pearance of vegetable cells, shown in figures 1’ and 2’, must at * Cross section of ligneous cells containing stratified deposit.