242 
VELOC RL: 
[JANUARY 14, 1897 
suffice it to say that the subject is still enshrouded in 
mystery. 
Although some, if not all, of the celluloses more or 
less readily undergo hydrolysis under natural conditions 
in plants, the difficulty with which cotton cellulose is 
resolved by acid hydrolysts is surprising in comparison 
with the readiness with which starch is attacked ; and 
when hydrolysis takes place, the tendency is to form 
dextrose : in no case has the production of a substance 
corresponding to that of maltose from starch been 
observed. How are these and other peculiarities to be 
explained? At present the only thing clear to us is 
that although fundamentally both dextrose derivatives, 
cellulose and starch are seemingly constructed on different 
types ; so that the conversion of one into the other, in 
whichever direction it may occur, involves a passage 
through dextrose. 
Messrs. Cross and Bevan attach great importance to 
the formation from cellulose of a large quantity—3o to 
35 per cent.—of acetic acid on fusing it with alkali, a 
behaviour which no other carbohydrate exhibits; to 
account for this, they assume that cellulose contains the 
group CO.CH,, and they are inclined to think that this 
forms part of aclosed chain of six carbon atoms constituting 
the fundamental C, group of the carbohydrate; but in the 
absence of definite evidence, so unconventional a view 
can only be regarded as a working hypothesis put forward 
with the object of emphasising the peculiarities of 
cellulose in comparison with other carbohydrates. 
There are, at least, two other types of cellulose which 
are far more widely distributed in the plant world than is 
that of the cotton type, viz. those obtained from woods 
and ligneous tissues generally, and those from cereal 
straws, esparto, &c. ; but such celluloses contain a larger 
proportion of oxygen, and are in fact orycel/uloses—so 
that, strictly speaking, they are not carbohydrates : they 
are characterised by yielding more or less furfuraldehyde 
on distillation with muriatic acid, wood cellulose giving 
from two to six per cent., and esparto as much as twelve. 
The ligno-celluloses constitute another class, belonging, 
however, to the group of compound celluloses, of which 
there seem to be many varieties ; they contain a non- 
cellulose constituent almost of a benzenoid character. 
All these are much less resistant than cotton cellulose. 
In a recent communication to the Chemical Society 
Messrs. Cross, Bevan, and Smith have shown that it is 
possible, by a process of regulated hydrolysis, to re- 
solve the cereal straws into a resistant cellulose and a 
substance which they believe to be a formal-pentose, 
eas 
CoHaOsy oy CHa they regard this as the primary 
source of the furfural obtained on hydrolysing many 
celluloses. Furthermore, they find that the substance of 
this type varies in character with the stage of growth, 
being completely fermentable at an early stage, but not 
in the later stages. This discovery marks an important 
advance in our knowledge, and its development may be 
looked forward to with the greatest interest. 
Finally, it is to be noted that in addition to celluloses 
primarily derived from ordinary dextrose, others exist 
in the formation of which isomerides of dextrose have 
taken part—vegetable ivory, for example, yields instead 
NOL 1420, YORE 55 
of dextrose the closely related substance mannose on 
hydrolysis, mannose differing from dextrose only in the 
relatively different position of the groups associated with 
the asymmetric carbon atom next the COH group. 
These illustrations will suffice to show how complex 
a chapter in organic chemistry we have to deal with in 
considering the celluloses ; but it is only in recent times, 
and in no small measure owing to Messrs. Cross and 
Bevan’s work, that we have been led to appreciate this fact. 
A perusal of their book will show how, as yet, we have 
but touched the outermost fringe of the inquiry into their 
nature, metamorphoses and origin, and how fertile, but 
at the same time infinitely difficult, a field they present 
for research. 
It is almost impossible to exaggerate the value of a 
thorough knowledge of all that relates to the celluloses, 
when we consider the astonishing variety of uses to which 
they are put, and the importance of the industries in 
which they constitute the raw material. Thus we not 
only clothe ourselves largely with cellulose in the form 
of cotton and linen fabrics, and make from it the paper 
on which we write and on which we print our books, 
besides using it for a multitude of other peaceful pur- 
poses, but even convert it into guncotton, and from this 
fashion smokeless powder wherewith to confound our 
enemies: indeed, no more striking illustration of the 
revolution in our practices that science is effecting could 
be given than is afforded by the fact that a material like 
gunpowder, after being in use during so many centuries, 
should have been suddenly, almost entirely, displaced 
by the cellulose nitrates and the closely related nitro- 
glycerin— the glycerin, from which the latter is made, 
also being obtained largely from vegetable sources as well 
as from animal fats, and being procurable as a bye-pro- 
duct, in large quantity, because our modern civilisation 
has imposed upon us the fashion of constantly washing 
with the aid of soap, which we are impelled to buy by 
ubiquitous advertisements. 
Now that the plastic nature of the celluloses is becoming 
understood, it is to be expected that they will be made 
use of in many other equally striking novel ways: the 
projected manufacture of a substitute for silk through the 
agency of nitrated cellulose is a case in point. 
Messrs. Cross and Bevan have much to say on the 
quality of paper on which permanent records should be 
printed—undoubtedly a question of great importance, 
which has in no way received the attention it deserves. 
Their book is printed upon a paper carefully selected as 
composed of “ normal” celluloses, to the exclusion of the 
inferior celluloses ordinarily employed in the manufacture 
of printing papers ; and it certainly affords an agreeable 
contrast in this respect to the majority of books issued 
at the present day. Formerly, when paper was made of 
rags, and china clay was used with a very sparing hand, 
the material was both strong and little liable to undergo 
deterioration under ordinary influences—mazs nous avons 
changé tout cela. Nowadays not only is a prodigal use 
made of china clay, but the place of rags is very largely 
taken by wood and straw. As already pointed out, the 
celluloses derived from such sources are far less resistant 
than cotton cellulose ; in fact, all papers made from such 
materials are liable to suffer discolouration under the 
