Scientific American Supplement, No. 455, September 20, 1884Various
Science
Scientific American Supplement, No. 455, September 20, 1884
Various
Science -- Periodicals
C. Schmitt and A. Coblenzl have made a careful investigation of the
unfermentable substances found in commercial starch sugars, and have
succeeded in isolating a definite compound, to which they give the name
gallisin. The method of separation and purification which they made use of
is as follows: 5 kilogrammes of commercial starch sugar were allowed to
ferment. At a temperature of 18-20° C. and with a solution containing 20
per cent. the fermentation was complete in five to six days. It was
filtered; the perfectly clear, almost colorless, liquid evaporated as far
as possible on the water-bath, and the sirup while still warm brought into
a good-sized flask. The sirup was then well shaken with a large excess of
absolute alcohol, when it became viscous, but did not mix with the
alcohol. The latter was poured off, replaced by fresh alcohol, and again
shaken. When this shaking with alcohol has been repeated several times,
the sirup is finally changed to a yellowish-gray mass. This is now brought
into a large mortar, and rubbed up under a mixture of alcohol and ether.
After some time the whole mass is transformed into a gray powder. It is
quickly filtered off with the aid of an aspirator, washed with alcohol and
then with ether, and brought under a desiccator with concentrated
sulphuric acid. In order to purify the substance, it is dissolved in water
and treated with bone-black. The solution is then evaporated to a sirup,
and this poured into a mixture of equal parts of anhydrous alcohol and
ether. In this way the new compound is obtained as a very fine, pure white
powder which rapidly settles. It has much the appearance of starch. Under
the microscope it is perfectly amorphous. In the air it deliquesces much
more rapidly than ignited calcium chloride.
Treated with dilute mineral acids or oxalic acid on the water-bath
gallisin is transformed into dextrose. It does not ferment when treated in
water solution with fresh yeast. The analyses led to the formula
C_{12}H_{24}O_{10}. When treated under pressure with three times its
weight of acetic anhydride at 130-140° it dissolves perfectly. From the
solution a product was separated which on analysis gave results agreeing
with the formula C_{12}H_{18}O_{10}(C_{2}H_{3}O)_{6}. The substance
appears therefore to be hexacetylgallisin.
Physiological experiments on lower animals and human beings demonstrated
clearly that gallisin has neither directly nor indirectly any injurious
effect on the health.--_Berichte der Deutschen Chemischen Gesellschaft,
17, 1000; Amer. Chem. Jour._
* * * * *
THE COMBINING WEIGHTS, VOLUMES, AND SPECIFIC GRAVITIES OF ELEMENTS AND
COMPOUNDS.
Under the title of "Figures Worth Studying," Mr. William Farmer, of New
York, read a paper before a recent meeting of the Society of Gas Lighting,
from which the _American Gas Light Journal_ gives the following:
Public-domain text, read in full here on John Shaqi.
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