7 |
|_______________________________|______|______|________|_________|_______|

The proportion of pentosanes (furfuroids) removed, i.e. hydrolysed by
boiling with hydrochloric acid of 2.5 p.ct. HCl, is shown by the
following estimations of furfural:

_________________________________________________________________
| | | | |
| | Birch | Sugar maple | |
| |______________|_______________| Apricot |
| | | | | | stones |
| | Bark | Wood | Outer | Inner | |
| | | | wood | wood | |
|________________________|_______|______|_______|_______|_________|
| | | | | | |
| In original substance | 16.7 | 19.6 | 18.2 | 20.7 | 18.4 |
| | | | | | |
| In residue from action | 6.53 | 8.6 | 4.9 | 6.4 | 7.0 |
| of 2.5 p.ct. HCl | | | | | |
|________________________|_______|______|_______|_______|_________|

_Wood Gum._--The paper contains some observations on the various methods
of isolating this product. Attention is directed to the necessary
impurity of the product, and to the fact that the numbers for furfural
and for the xylose yielded by hydrolysis are considerably less than for
a pure pentosane.

_Estimation of Cellulose._--The author investigated the process of Lange
and the 'celluloses' obtained from various raw materials. The products
from the woods of birch and maple contained furfural-yielding
constituents, represented by yields of 6-8 p.ct. furfural. Preference is
given to the process by comparison with others, at the same time that it
is recommended in all cases to examine the product for furfural
quantitatively, converting the numbers into pentosane equivalents, and
subtracting from the total 'cellulose' to give the true cellulose.

ZUR KENNTNISS DER MUTTERSUBSTANZEN DES HOLZGUMMI.

E. WINTERSTEIN (Ztschr. Physiol. Chem., 1892, 381).

~ON THE MOTHER SUBSTANCES OF WOOD-GUM.~

(p. 188) According to the text-books beech-wood may be regarded as the
typical raw material for the preparation of the laboratory product known
as wood-gum. The author has subjected beech-wood and beech-wood
cellulose (Schulze process) to a range