A Manual of the Chemistry of the Carbon Compounds

TB£ CARBON COMPOUNDS. 287
dissolve in a solution of sugar when an alkali is present; the blue
copper solution is slowly decomposed on boiling with the separation
of red cuprous oxide. When silver Salts or gold salts are heated with
a solution of sugar, the metals are reduced to the metallic state.
When an aqueous solution of sugar is saturated with chlorine, and
the liquid is then treated with silver oxide, glneonic acid C6Hl2O7,
an isomeride of roannitic noid, is formed. The acid is a sour, syrupy
liquid, bnt the calcium and barium salts crystallize well
SYNANTHKOSE C^H^O,,
Occurs in the tubers of Dahlia variaMlis, Helianllws tuberosum, and
of other Composite. It is a light amorphous powder, which is very
deliquescent, naa no sweet taste, and no action on polarized light.
Dilute acids or yeast change it into levuloae and dextrose, and on
oxidation it yields saccharic acid.
MII.K-STJGAK
Is an important constituent of the milk of mammals, and has also
been found together with cane-sugar in the juice of the Sapodilla
{Acfiras sapola). It is prepared on the large scale, chiefly in Switzerland,
by evaporating "whey" to a syrupy state. Milk-sugar forma
hard rhombic prisms, losing their water of crystallization at 140°. It
disaolves in 6 parts of cold and 2*5 parts of boiling water, and has
only a faint sweet taste, When a large quantity of yeast ia added to
a dilute solution of milk-sugar, fermentation sets in only gradually.
By using old cheese as ferment, milk-sugar is converted into lactic
acid; at the same time some manuite and alcohol are formed, the
latter in larger quantity if the solution be very dilute, When a
concentrated solution of milk-sugar is treated with sodium amalgam,
a part is reduced to dulcite, and another gives ethyl, iaopropyl, and
hexyl alcohol
Nitric acid oxidizes milk-sugar to mucic and saccharic acids, whilst
cane-sugar yields only saccharic acid, It also combines with bases
like cane-sugar, and reduces an alkaline copper-solution, and solutions
of the salts of the noble metals.
When milk-sugar is heated with bromine and water to 100°, it
combines with the bromine, forming a compound having probably the
formula C6HiaBrj08. This body is easily acted upon by silver oxide,
and lactonic add CaH10Oa is formed, This monobasic acid is readily
soluble in water, and crystallizes in fine needles; by further oxidation
it is converted into mucic acid.