or acids. The cellulose varies in amount from
80 to 50%, and the lignone varies inversely as the degree of
lignification, that is, from the lignified bast fibre of annuals, of
which jute is a type, to the dense tissues of the perennial
dicotyledonous woods, typified by the beech. The empirical formula of
the lignone complex varies from C19H22O9 (jute) to C26H30O10 (pine
wood). In certain reactions the non-cellulose or lignone constituents
are selectively converted into soluble derivatives, and may be separated
as such from the cellulose which is left; for example, chlorination
gives products soluble in sodium sulphite solution, by the combination
of unsaturated groups of the lignone with the halogen, while digestion
with bisulphite solutions at elevated temperatures (140 deg.-160 deg.)
gives soluble sulphonated derivatives. This last reaction is employed
industrially in the preparation of cellulose for paper-making from
coniferous woods. These reactions are "quantitative" since they depend
upon well-defined constitutional features of the lignone complex, and
the resolution of the ligno-cellulose takes place with no further change
in the lignone than the synthetical combination with the substituting
groups. The constituent groups of the lignone specifically reacting are
of benzenoid type of the probable form

HC
//\
HC // \CO
| |
H2C \ /CO
\ /
CO ,

deduced from the similarity of the chlorinated derivatives to
mairogallol, the product of the action of chlorine on pyrogallol in
acetic acid solution (A. Hantzsch, _Ber._ 20, p. 2033). The complex
contains methoxy (OCH3) groups. There is also present a residue which is
readily broken down by oxidizing agents, and indeed by simple
hydrolysis, to acetic acid. Another important group of actual
constituents are pentosanes--partially isolated as "wood gum" by
solution in alkalis--and furfural derivatives (hydroxy furfurals)
derived from these. The actual constitutional relationships of these
main groups, as well as the localization of the methoxy groups, are
still problematical.

Certain colour reactions are characteristic, though they are in some
cases reactions of certain constituents invariably present in the
natural forms of the ligno-cellulose; which may be removed without
affecting the essential character of the lignone complex. Aniline salts
generally give a yellow coloration, dimethyl-para-phenylenediamine gives
a dee