TISSUE

in biology, is a term applied to any structure composed of cells and cell products. The functions and characters of the predominant cellular units nece arily determine the nature of a ti ue, which may be cellular, o eous, muscular, connective, glandular, nervous, and so forth. The principal substance of the elastic fibre characteristic of certain ti ues is elastin, a body closely resembling albumin, but without any sulphur. Vegetable ti ues are generally simpler than those of animals, and consist mainly of (1) epidermal or covering cells, (2) fibro-vascular bundles, and (3) fundamental or le highly differential cells.