t was found impossible to isolate the
compound.

UNTERSUCHUNGEN UEBER DIE PENTOSANBESTIMMUNG MITTELST DER
SALZSAeURE-PHLORO-GLUCIN-METHODE.[8]

E. KROeBER (Journ. f. Landwirthschaft, 1901, 357).

~INVESTIGATION OF THE HYDROCHLORIC ACID-PHLOROGLUCINOL METHOD OF
DETERMINING PENTOSANES.~

This paper is the most complete investigation yet published of the now
well-known method of precipitating and estimating furfural in acid
solution by means of the trihydric phenol. In the last section of the
paper is contained the most important result, the proof that the
insoluble phloroglucide is formed according to the reaction

C_{5}H_{4}O_{2} + C_{6}H_{6}O_{3} - 2H_{2}O = C_{11}H_{6}O_{3},

also, by varying the proportions of the pure reagents interacting, that
the condensation takes place invariably according to this equation.

Incidentally the following points were also established:--The solubility
of the phloroglucide, under the conditions of finally separating in a
condition for drying and weighing, is 1 mgr. per 100 c.c. of total
solution, made up of the original acid solution, in which the
precipitation takes place, and the wash-water required to purify from
the acid. The phloroglucide is hygroscopic, and must be weighed out of
contact with the air. The presence of diresorcinol is without influence
on the result, provided a sufficient excess of actual phloroglucinol is
employed. Thus even with a preparation containing 30 p.ct. of its weight
of diresorcinol the influence of the latter is eliminated, provided a
weight be taken equal to twice that of the furfural to be precipitated.
The phenol must be perfectly dissolved by warming with dilute HCl (1.06
sp.gr.) before adding to the furfural solution. For collecting the
precipitate of phloroglucide the author employs the Gooch crucible.

The paper contains a large number of quantitative results in proof of
the various points established, and concludes with elaborate tables,
giving the equivalents in the known pentoses and their anhydrides for
any given weight of phloroglucide from 0.050 to 0.300 grm.

UEBER DEN PENTOSAN-GEHALT VERSCHIEDENER MATERIALIEN.

B. TOLLENS and H. GLAUBITZ (J. fuer Landwirthschaft, 1897, 97).

~ON THE PENTOSANE CONSTITUENTS OF FODDER-PLANTS AND MALT.~

(p. 171) (a) The authors have re-determined the yield of furfural from
a large range of plant-products, using the phloroglucol method. The
numbers approximate closely to those obtained b