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