by Cross and Bevan, who have investigated it. It is not identical with
ordinary cellulose, for if we take a little of the jute, soak it in
dilute acid, then in chloride of lime or hypochlorite of soda, and
finally pass it through a bath of sulphite of soda, a beautiful crimson
colour develops upon it, not developed in the case of cellulose (cotton,
linen, etc.). It is certain that it is a kind of cellulose, but still
not identical with true cellulose. All animal fibres, when burnt, emit a
peculiar empyreumatic odour resembling that from burnt feathers, an
odour which no vegetable fibre under like circumstances emits. Hence a
good test is to burn a piece of the fibre in a lamp flame, and notice
the odour. All vegetable fibres are easily tendered, or rendered rotten,
by the action of even dilute mineral acids; with the additional action
of steam, the effect is much more rapid, as also if the fibre is allowed
to dry with the acid upon or in it. Animal fibres are not nearly so
sensitive under these conditions. But whereas caustic alkalis have not
much effect on vegetable fibres, if kept out of contact with the air,
the animal fibres are very quickly attacked. Superheated steam alone has
but little effect on cotton or vegetable fibres, but it would fuse or
melt wool. Based on these differences, methods have been devised and
patented for treating mixed woollen and cotton tissues--(1) with
hydrochloric acid gas, or moistening with dilute hydrochloric acid and
steaming, to remove all the cotton fibre; or (2) with a jet of
superheated steam, under a pressure of 5 atmospheres (75 lb. per square
inch), when the woollen fibre is simply melted out of the tissue, and
sinks to the bottom of the vessel, a vegetable tissue remaining
(Heddebault). If we write on paper with dilute sulphuric acid, and dry
and then heat the place written upon, the cellulose is destroyed and
charred, and we get black writing produced. The principle involved is
the same as in the separation of cotton from mixed woollen and cotton
goods by means of sulphuric acid or vitriol. The fabric containing