quently
a nucleolus, which are capable of assimilating nutriment or food,
propagating themselves either into others of the same form or into fixed
cells of another outward appearance and different function but of the
same constitution. It is simply in the mode of the grouping of these
elements that we have the variation in tissues, as (1) loose connective
tissue, (2) aponeurosis and tendons, (3) muscles, (4) cartilage, (5)
bones, (6) epithelia and endothelia, (7) nerves.

(1) Loose connective tissue forms the great framework, or scaffolding,
of the body, and is found under the skin, between the muscles
surrounding the bones and blood vessels, and entering into the
structures of almost all the organs. In this the fibers are loosely
meshed together like a sponge, leaving spaces in which the nutrient
fluid and cells are irregularly distributed. This tissue we find in the
skin, in the spaces between the organs of the body where fat
accumulates, and as the framework of all glands.

(2) Aponeurosis and tendons are structures which serve for the
termination of muscles and for their contention, and for the attachment
of bones together. In these the fibers are more frequent and dense, and
are arranged with regularity, either crossing each other or lying
parallel, and here the cells are found in minimum quantity.

(3) In the muscles the cells lie end to end, forming long fibers which
have the power of contraction, and the connective tissue is in small
quantity, serving the passive purpose of a band around the contractile
elements.

(4) In cartilage a mass of firm amorphous substance, with no vascularity
and little vitality, forms the bed for the chondroplasts, or cells of
this tissue.

(5) Bone differs from the above in having the amorphous matter
impregnated with lime salts, which gives it its rigidity and firmness.

(6) Epithelia and endothelia, or the membranes which cover the body and
line all its cavities and glands, are made up of single or stratified
and multiple layers of cells bound together by a glue of amorphous
substance and resting on a layer composed of fibers. When the membrane
serves for secreting or excreting purposes, as in the salivary glands or
the kidneys, it is usually simple; when it serves the mechanical purpose
of protecting a part, as over the tongue or skin, it is invariably
multiple and stratified, the surface wearing away while new cells
replace it from beneath.

(7) In nerves, stellate cells