at contained in
_laevulose_, and that such groups constitute the main or essential part
of the molecule. Secondly, that similar groupings are contained in
_starches_ and _dextrins_, but that the proportion of such groupings
represents a relatively small part of the whole structure.

The nature of this grouping is, according to the generally accepted
constitution of _laevulose_, the six-carbon chain with a ketonic group:

C.C.C.C.C.C
|| .
O

But the results might, on the other hand, be considered indicative of
the anhydride or 'lacton' grouping, which Tollens suggested for
laevulose:

C.C.C.C.C.C
\ /
\ / .
O

The latter very simply represents the formation of
omega-brommethylfurfural from laevulose,[7]

------O-----
| H H |
| | | |
OH.C-----C---C---C--C-----CH_{2}.OH
H_{2} OH OH OH H

giving

H H
HC.C:C.C:C.CH_{2}Br
|| \ / ,
O \ /
O

although by a little further 'manipulation' of the symbols the change
could, of course, be represented by reference to the ketonic formula.

~The Ketonic Constitution of Cellulose.~

C. F. CROSS and E. J. BEVAN (J. Chem. Soc., 1901, 366).

In this paper the authors discuss more fully the theoretical bearings of
the observations of Fenton and Gostling, the two papers being
simultaneously communicated. The paper is mainly devoted to a review of
the antecedent evidence, chemical and physiological, and to a general
summing up in favour of the view that cellulose is a polyketose
(anhydride).

* * * * *

(p. 79) ~Composition of the Seed Hair of Eriodendron~ (~Anf.~)--Some
interest attaches to the results of an analytical investigation which we
have made of this silky floss. There is little doubt that cotton is
entirely exceptional in its characteristics: both in structure and
chemical composition it fails to show any adaptation to what we may
regard as the _more obvious_ functions of a seed hair--which certainly
do not demand either structural strength or chemical resistance. The
following numbers determined for the kapok differentiate it widely from
the cottons:

Ash, 1.3; moisture, 9.3; alkaline hydrolysis (loss) (a) 16.7,
(b) 21.8. Cellulose, by chlorination, &c., 71.1.

In reacting with chloride it shows the presence of unsaturated groups,
sim