Researches on Cellulose | Page 4

with which they occur, combined or mixed. A chemist
familiar with such types as rhea or ramie (pectocellulose), jute
(lignocellulose), and raffia (cutocellulose) knows exactly the specific
treatment to apply to each for isolating the cellulose, and must view
with some surprise the appearance at this date of such 'universal
prescriptions' as the process in question.
The third division of our plan of arrangement comprised the synthetical
derivatives of the celluloses, the sulphocarbonates first, as peculiarly
characteristic, and then the esters, chiefly the acetates, benzoates, and
nitrates. To these, investigators appear to have devoted but little
attention, and the contribution of new matter in the present volume is
mainly the result of our own researches. It will appear from this work
that an exhaustive study of the cellulose esters promises to assist very
definitely in the study of constitutional problems.
This brings us to the fourth and, to the theoretical chemist, the most
important aspect of the subject, the problem of the actual molecular
structure of the celluloses and compound celluloses. It is herein we are
of opinion that the subject makes a 'law unto itself.' If the constitution
of starch is shrouded in mystery and can only be vaguely expressed by
generalising a complex mass of statistics of its successive hydrolyses,
we can only still more vaguely guess at the distance which separates us
from a mental picture of the cellulose unit. We endeavour to show by
our later investigations that this problem merges into that of the actual
structure of cellulose in the mass. It is definitely ascertained that a
change in the molecule, or reacting unit, of a cellulose, proportionately

affects the structural properties of the derived compounds, both
sulphocarbonates and esters. This is at least an indication that the
properties of the visible aggregates are directly related to the actual
configuration of the chemical units. But it appears that we are barred
from the present discussion of such a problem in absence of any theory
of the solid state generally, but more particularly of those forms of
matter which are grouped together as 'colloids.'
Cellulose is distinguished by its inherent constructive functions, and
these functions take effect in the plastic or colloidal condition of the
substance. These properties are equally conspicuous in the synthetical
derivatives of the compound. Without reference, therefore, to further
speculations, and not deterred by any apparent hopelessness of solving
so large a problem, it is clear that we have to exhaust this field by exact
measurements of all the constants which can be reduced to numerical
expression. It is most likely that the issue may conflict with some of
our current views of the molecular state which are largely drawn from a
study of the relatively dissociated forms of matter. But such conflicts
are only those of enlargement, and we anticipate that all chemists look
for an enlargement of the molecular horizon precisely in those regions
where the forces of cell-life manifest themselves.
The cellulose group has been further differentiated by later
investigations. The fibrous celluloses of which the typical members
receive important industrial applications, graduate by insensible stages
into the hemicelluloses which may be regarded as a well-established
sub-group. In considering their morphological and functional
relationships it is evident that the graduation accords with their
structure and the less permanent functions which they fulfil. They are
aggregates of monoses of the various types, chiefly mannose, galactose,
dextrose, &c., so far as they have been investigated.
Closely connected with this group are the constituents of the tissues of
fungi. The recent researches of Winterstein and Gilson, which are noted
in this present volume, have established definitely that they contain a
nitrogenous group in intimate combination with a carbohydrate
complex. This group is closely related to chitin, yielding glucosamin

and acetic acid as products of ultimate hydrolysis. Special interest
attaches to these residues, as they are in a sense intermediate products
between the great groups of the carbohydrates and proteids (E. Fischer,
Ber. 19, 1920), and their further investigation by physiological methods
may be expected to disclose a genetic connection.
The lignocelluloses have been further investigated. Certain new types
have been added, notably a soluble or 'pectic' form isolated from the
juice of the white currant (p. 152), and the pith-like wood of the
Æschynomene (p. 135).
Further researches on the typical fibrous lignocellulose have given us a
basis for correcting some of the conclusions recorded in our original
work, and a study of the esters has thrown some light on the
constitution of the complex (p. 130).
Of importance also is the identification of the hydroxyfurfurals as
constituents of the lignocelluloses generally, and the proof that the
characteristic colour-reactions with phenols (phloroglucinol) may be
ascribed to the presence of these compounds (p. 116).
The pectocelluloses have not been the subject of systematic chemical
investigation,