A Manual of the Chemistry of the Carbon Compounds

293 2BJ? QHEMI8TR7 OF
0A.LACT08E
Is formed (probably together with dextrose) by boiling milk-sugar
with very dilute sulphurio acid. It crystallizes in uucroscopio prisms,
and is readily soluble in water.
It is veiy easily fermentable, and reduces alkaline copper-solutions
like the two other glucoses. From dextrose it differs not only by the
greater dextro-rotatory power of its solution, but also by yielding on
•oxidation only mucic acid (twice as much as the same weight of
milk-sugar). When inverted milk-sugar is treated with water and
sodium amalgam, it yields dulcite and mannifa
Besides these three glucoses, we are acquainted with several other
varieties, which all possess the property of being readily fermentable.
The following bodies, however, differ from the glucoses by not undergoing
fermentation in ptesence of yeaat, and by not being converted
into a glucose or fermentable sugar by the actioD of dilute acids.
SorMn C6H12O6 occurs in the berries of the mountain-ash, and forms
large crystals,Having a very sweet taste. When treated with chlorine
and silver oxide, it is oxidized to glycollic acid.
Inosite 09H«Oa + 2HjO has been found in the muscular substance
of the heart, lungs, liver, kidneys, &c, in green kidney-beans and
the unripe fruits of other Papilionacese, and also in other plants.
It forms large transparent rhombio crystals, which lose their water of
crystallization when exposed to the air. It is soluble in water, and
has a sweet taste. By the aotion of dilute nitric acid it is oxidized to
oxalic aoid, bub the concentrated acid converts it into aa explosive
nitric ether, called nitro-inosiU.CJl^SO^Q.
Eucalyn GfinO. is obtained together with ethyl alcohol by tiie
fermentation of melitose, and forms an unorystallizable syrup ;—
+ H8O = 2CO2 + 20^0 + C8HiaOa
(3) AMXXOSES (C4O,0H6)n.
STABCff, OR AMYLOT.
This important and widely-diffused body is found to a greater or
leas extent in nearly every plant It is most abundant in grab, in
rice, and a great many other seeds, and in certain roots and tubes, as
in potato, And in the stem of several palm-trees.
Starch is a soft, white powder, which under the microscope is seen
•to be destitute of crystalline structure, being made up of transparent
rounded granules, possessing an organized struoture. The starch-
(granules of different plants vary much both ia form and magnitude
(see Pigs. 12 and 13), the average diameter being of—