is a mixture of collodion and camphor. The hexanitrate,
C_{12}H_{14}(NO_{3})_{6}O_{4}, is the violent explosive known as
_gun-cotton_.

Gentler oxidizing agents, such as "bleaching powder," etc., have no effect
upon cellulose, and hence are extensively used in the treatment of cotton
and other vegetable fibers, in preparation for their use in the manufacture
of textiles, paper, etc.

Cellulose is indigestible in the alimentary tract of animals, but the
putrefactive bacteria which are generally present there ferment it, with
the production of acids of the "fatty acid" series, carbon dioxide,
methane, and hydrogen. Excessive fermentations of this kind are responsible
for the distressing phenomenon known as "bloat."

The =compound celluloses= comprise the larger proportion of the material of
the woody stems of plants. They consist of a base of true cellulose, which
is either encrusted with or chemically combined with some non-cellulose
constituent. Depending upon the nature of the non-cellulose component, the
compound celluloses are divided into three main groups, known respectively
as (1) ligno-celluloses, (2) pecto-celluloses, and (3) adipo-, or
cuto-celluloses. As the names indicate, the non-cellulose component in the
first group is lignin; in the second, pectic substances; and in the third,
fats or waxes.

=Ligno-celluloses.=--In the young plant cell, the cell-walls consist of
practically pure cellulose; but as the plant grows older, this becomes
permeated with lignin, or woody fiber, until in the stem of a tree, for
example, the proportion of cellulose in the tissue is only 50 to 60 per
cent. In the preparation of wood pulp for the manufacture of paper, the
lignin materials are dissolved off by means of various chemical reagents,
leaving the cellulose fibers in nearly pure form for use as paper. The
lignin material generally consists of two types of substances, one of which
contains a closed-ring nucleus of unknown composition and the other is
probably a pentosan. These materials are so extremely difficult to
hydrolyze that their composition has not yet been definitely determined.

=Pecto-celluloses= are found in various species of flowering plants; those
which are present in the stems and roots being true pecto-celluloses, while
those which are found in fruits and seeds contain mucilages rather than
pectose derivatives, and are generally designated as "muco-celluloses." The
exceedingly inert character of these co