Researches on Cellulose | Page 6

important facts obscured or misinterpreted, but there was a barrenness
of suggestion of genetic relationships. As the group has been widened
very much beyond these limits, it is clear that if any group term or
designation is to be retained that of 'furfuroid' is 'neutral' in character,
and equally applicable to saturated substances of such widely
divergent chemical character as pentoses, hexosones, glycuronic acid,
and perhaps, most important of all, levulose itself, all of which are
susceptible of condensation to furfural or furfurane derivatives, as well
as to those unsaturated compounds, constituents of plant tissues which
are already furfurane derivatives.

From the chemical point of view such terms are perhaps superfluous.
But physiological relationships have a significance of their own; and
there is a physiological or functional cohesion marking this group
which calls for recognition, at least for the time, and we therefore
propose to retain the term furfuroid.[1]
~General Experimental Methods.~--In the investigation of the cellulose
group it is clear that methods of ultimate hydrolysis are of first
importance. None are so convenient as those which are based on the
action of sulphuric acid, more or less concentrated
(H{2}SO{4}.3H{2}O - H{2}SO{4}H{2}O). Such methods have been
frequently employed in the investigations noted in this volume. We
notice a common deficiency in the interpretation of the results. It
appears to be sufficient to isolate and identify a crystalline monose,
without reference to the yield or proportion to the parent substance, to
establish some main point in connection with its constitution. On the
other hand, it is clear that in hydrolysing a given cellulose-complex we
ought to aim at complete, i.e. quantitative, statistics. The hydrolytic
transformation of starch to dextrins and maltose has been followed in
this way, and the methods may serve as a model to which cellulose
transformations should be approximated. In fact, what is very much
wanted is a systematic re-examination of the typical celluloses in which
all the constants of the terms between the original and the ultimate
monose groups shall be determined. Such constants are similar to those
for the starch-dextrose series, viz. opticity and cupric reduction.
Various methods of fractionation are similarly available, chiefly the
precipitation of the intermediate 'dextrins' by alcohol.
Where the original celluloses are homogeneous we should thus obtain
transformation series, similarly expressed to those of starch. In the
case of the celluloses which are mixtures, or of complex constitution,
there are various methods of either fractionating the original, or of
selectively attacking particular monoses resulting from the
transformation. By methods which are approximately quantitative a
mixture of groups, such as we have, for instance, in jute cellulose,
could be followed through the several stages of their resolution into
monoses. To put the matter generally, in these colloidal and complex

carbohydrates the ordinary physical criteria of molecular weight are
wanting. Therefore, we cannot determine the relationship of a given
product of decomposition to the parent molecule save by means of a
quantitative mass-proportion. Physical criteria are only of determining
value when associated with such constants as cupric reduction, and
these, again, must be referred to some arbitrary initial weight, such as,
for convenience, 100 parts of the original.
Instead of adopting these methods, without which, as a typical case, the
mechanism of starch conversions could not have been followed, we
have been content with a purely qualitative study of the analogous
series obtainable from the celluloses under the action of sulphuric acid.
A very important field of investigation lies open, especially to those
who are generally familiar with the methods of studying starch
conversions; and we may hope in this direction for a series of valuable
contributions to the problem of the actual constitution of the celluloses.
FOOTNOTES:
[1] In this we are confirmed by other writers. See Tollens, J. für Landw.
1901, p. 27.

SECTION I. GENERAL CHEMISTRY OF THE TYPICAL COTTON
CELLULOSE
(p. 3)[2] ~Ash Constituents.~--It is frequently asserted that silica has a
structural function sui generis in the plant skeleton, having a
relationship to the cellulosic constituents of the plant, distinct from that
of the inorganic ash components with which it is associated. It should
be noted that the matter has been specifically investigated in two
directions. In Berl. Ber. 5, 568 (A. Ladenburg), and again in 11, 822
(W. Lange), appear two papers 'On the Nature of Plant Constituents
containing Silicon,' which contain the results of experimental
investigations of equisetum species--distinguished for their
exceptionally high 'ash' with large proportion of silica--to determine
whether there are any grounds for assuming the existence of

silicon-organic compounds in the plant, the analogues of carbon
compounds. The conclusions arrived at are entirely negative. In
reference to the second assumption that the cuticular tissues of cereal
straws, of esparto, of the bamboo, owe their special properties to
siliceous components, it has been shown by direct experiment