p red coloration, phloroglucin in hydrochloric acid gives a crimson
coloration. Reactions more definitely characteristic of the lignone
are:--ferric ferrocyanide, which is taken up and transformed into
Prussian blue throughout the fibre, without affecting its structure,
although there may be as much as a 50% gain in weight; iodine in
potassium iodide solution gives a deep brown colour due to absorption of
the halogen, a reaction which admits of quantitative application, i.e.
as a measure of the proportion of ligno-cellulose in a fibrous mixture;
nitric acid gives a deep orange yellow coloration; digested with the
dilute acid (5-10% HNO3) at 50 deg. the ligno-celluloses are entirely
resolved, the lignone complex being attacked and dissolved in the form
of nitroso-ketonic acids, which, on continued heating, are finally
resolved to oxalic, acetic, formic and carbonic acids.

_Derivatives of Ligno-cellulose._--By reaction with chlorine jute yields
the derivative C19H18Cl4O9, soluble in alcohol, and in acetic acid; this
derivative has the reactions of a quinone chloride. By reaction with
sodium sulphite it is converted into a hydroquinone sulphonate of deep
purple colour. The reaction of the ligno-celluloses (pine wood) with the
bisulphites yields the soluble derivatives of the general formula
C26H29O9.SO3H (containing two O.CH3 groups). Jute reacts with nitric
acid in presence of sulphuric acid to form nitrates; and with acetic
anhydride to form low acetates. It reacts with alkaline hydrates with
structural changes similar to those obtained with cotton; and by the
further action of benzoyl chloride and of carbon bisulphide upon the
resulting compounds there result the corresponding benzoates and
xanthates respectively. But these synthetical derivatives are mixtures
of cellulose and lignone derivatives, and so far of merely theoretical
interest.

_Decompositions of Ligno-cellulose._--In addition to the specific
resolutions above described which depend upon the distinctive chemical
characters of the cellulose and lignone respectively, the following may
be noted: to simple hydrolytic agents the two groups are equally
resistant, therefore by boiling with dilute acids or alkalis the groups
are attacked _pari passu_. Weak oxidants may also be used as bleaching
agents to remove coloured by-products without seriously attacking the
ligno-cellulose, which is obtained in its bleached form. Nitric acid of
all strengths effects complet