THURSDAY, JANUARY 14, 1897. 
CELLULOSE. —THE CHOICE OF PAPER FOR 
BOOKS. 
Cellulose : an Outline of the Chemistry of the Structural 
Elements of Plants with reference to their Natural 
History and Industrial Uses. By Cross and Bevan. 
Pp. 320. (London: Longmans, Green, and Co., 1895.) 
N O more aggravating book could be placed in the 
hands of a reviewer: inchoate in the highest 
degree, it deals with a subject of extraordinary interest 
and importance in an absolutely original manner; it 
teems with suggestions which those who can read between 
the lines will find of the greatest value ; but it is disfigured 
by an obscurity of diction which must materially diminish 
its usefulness, and to do it justice a degree of patience 
and long-suffering must be exercised which probably few 
possess. Certainly it has taken me a long time to screw 
up my courage to the point of venturing to publicly 
discuss its merits ; but the delay has served a good pur- 
pose: had I recorded my first impressions, they would 
have been highly unfavourable ; whereas I can now say 
that the more often I take the book in hand the more it 
fascinates me, and the more I realise how important are 
the problems it presents for consideration. In fact, what- 
ever the faults of the work, all who are in any way con- 
cerned with the manifold uses which cellulose subserves, 
whether in nature or art, must seek to appreciate its con- 
tents, and must study it as by far the most important 
contribution to the subject published since the appear- 
ance in 1876 of the magnificent fragment, entitled, “‘ Die 
Pflanzenfaser und ihre Aufbereitung flr die Technik,” 
by Dr. Hugo Miiller. A comparison of the two books 
shows how extraordinary is the progress made during 
the past twenty years ; and yet how absolutely ignorant 
we remain of the nature of cellulose. 
Many may ask, What is cellulose? To which we must 
reply, We cannot say! It is impossible at present to 
define it more exactly than as being the main element of 
the cellular structure of plants ; as the structural basis of 
the vegetable world—to use Messrs. Cross and Bevan’s 
expression, so that its German appellation, cell-stuff, gives 
in a single word the best definition possible. But whereas 
formerly we thought of it always in connection with 
cotton-wool, it is now becoming customary to associate 
the name with a variety of substances, and to regard 
cotton-wool cellulose as only the most highly developed 
term of a series of celluloses. 
Cellulose belongs to the great secret society we term 
carbohydrates—\ say secret, because all but the inferior 
members are sealed books to us. A carbohydrate is a 
compound in which carbon is associated with oxygen 
and hydrogen, these elements being present in the 
proportions in which they occur in water ; an important 
consideration to be borne in mind when the attempt is 
made to consistently define a cellulose. For years we 
lived under the comfortable conviction that the carbo- 
hydrates contained, if not six, some integral multiple of 
six carbon atoms in the molecule, and they were all 
natural products; but then it was discovered that 
NO. 1420, VOL. 55] 
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241 
ordinary gum arabic affords a carbohydrate containing 
only five atoms of carbon—ze. the pentose arabinose ; 
and more recently we have learnt to improve on 
nature, and have shown how vastly greater are 
our powers by raising the number of hexaldoses isomeric 
with ordinary honey glucose, C;H,,O0,, from three—the 
number obtained from natural sources—to eleven ; the 
maximum number possible being, we believe, sixteen : 
a sufficiently wonderful achievement ; in fact, probably 
the greatest feat recorded in the history of chemical 
discovery, and the more so when we consider that we 
have not only made them, but have also, we venture to 
believe, successfully allocated to the atoms in the mole- 
cule of each of the forms their relative positions in space. 
It may be added that we are now acquainted with a com- 
plete series of homologous “glucoses” containing from 
one up to nine carbon atoms, most of them being 
artificial products. 
Nature, however, has hitherto baffled us in the case 
of so well-defined a carbohydrate as ordinary sugar— 
call it, as we may, either cane or beet sugar, since but 
one and the same substance is procurable from either 
source, although many “educated” folk still insist on the 
contrary. Notwithstanding that we know the size of its 
molecule, we have not yet precisely determined its 
structure, which is proof that our analytic powers are 
after all but very limited, and that there is no relation 
between cheapness and constructiveness: as if there 
were, we should long ago have entirely mastered a 
material tons upon tons of which may be had in an 
almost pure state at about twopence a pound—in itself a 
sufficiently noteworthy circumstance ; indeed, no other 
article of commerce illustrates in so striking a manner the 
perfection attained in modern manufacturing processes. 
Above cane sugar, higher in the series, all is chaos: 
of dextrin, glycogen, inulin, starch and the celluloses, 
&c., we know no more than that in some way they are, 
with very few exceptions, derived from ordinary glucose ; 
it is generally supposed that their molecules are Azghly 
complex, but the evidence on this point is by no means 
complete. Progress is barred by the absence of methods 
of attacking such problems, and we must patiently await 
the arrival of the pioneers who will successfully penetrate 
into regions which we have hitherto always failed in ex- 
ploring beyond the frontiers. From this point of view, 
especially, men like Messrs. Cross and Bevan are particu- 
larly deserving of encouragement, as they have given 
clear proof of ability in opening up new lines of inquiry 
—by far the most valuable office to render at such a 
juncture. 
Cane sugar, C,,H.,O,,, and its congeners are with great 
facility resolved into two hexose molecules by hydrolysis ; 
and all other higher carbohydrates, excepting the cellu- 
loses, are without difficulty simplified by the action of 
dilute mineral acids and a number of enzymes. The 
behaviour of starch is altogether remarkable: when 
subjected to the action of an extract of malt, it is very 
rapidly attacked, even at ordinary temperatures, if 
previously gelatinised ; in the first instance, it is con- 
verted into soluble starch, and then into “dextrins” 
and maltose, the isomeride of cane sugar. This is not the 
place to enter into any discussion of the various “dex- 
trins,” or of the peculiarities which they manifest : 
M 
