CELLULAR TISSUE. This is the old term for a widely diffused animal texture, which has also received the names of areolar, reticular, filamentous, and connective tissue. if we make a cut through the skin, and proceed to raise it, we see that it is loosely connected with the subjacent parts by a soft, filamentous, elastic substance, which, when free front fat, has a white fleecy aspect. This is the tissue in question. It is also found underneath the serous and mucous membranes which are spread over internal surfaces, and serves to attach these membranes to the parts which they line. We likewise find it lying between the muscles, the blood-vessels, nerves, etc., occupy ing the interspaces between the different organs, and often investing each of them with a special sheath. While it thus connects and insulates entire organs, it at the same time performs a similar function in regard to the minute parts of which each organ is made up. Thus, for instance, in muscular tissue, it enters between the fibers of the muscle, uniting them into bundles; and similarly, it enters into glands, etc. This is
termed penetrating or parenchymal cellular tissue.
It is not only one of the most general and most entensively distributed of the tissues, but it is continuous through the whole organism, and may be traced without inter ruption from any one region of the body to any other. It is in consequence of this continuity that dropsical fluids, air, etc., effused into the C. T., may spread far from the spot where they were first introduced.
On examining a fragment of this tissue, when stretched out, we see with the naked eye that it presents the appearance of a multitude of fine, soft, colorless, elastic threads, like spun glass; intermixed with these are delicate films or lamina, crossing one another in all directions, and leaving open spaces, or areohn; hence the name of areolar tissue.
A small quantity of colorless transparent fluid is always present in this tissue; when' abnormally increased, it gives rise to the form of general dropsy known as anasarca. The microscopic characters of C. T. are briefly noticed in the article TISSUES, ANIMAL.