Principles of organic and physiological chemistry / by Carl Löwig ; translated by Daniel Breed.

  • Carl Jacob Löwig
Date:
1853
Catalogue details

Licence: Public Domain Mark

Credit: Principles of organic and physiological chemistry / by Carl Löwig ; translated by Daniel Breed. Source: Wellcome Collection.

    451/494 (page 443)
    bitches, restricted to carnivorous diet, contains no milk-sugar. Crystallizes in white quadrilateral columns, sharpened with two faces; hard, grates between the teeth, is dissolved in G parts cold water, and in from 3 to 4 parts of boiling, insoluble in alcohol and ether, tastes less sweet than the other sugar. By digestion with dilute sulphuric acid it is converted into grape-sugar; on the con¬ trary, diastase and yeast do not appear to cause it to ferment; however, the Baschkirs and Kalmucks prepare an intoxicating drink (kumis), by fermentation of mare’s milk. We obtain milk- sugar, by evaporating to syrup-thickness milk freed from the butter and cheese, the so-called whey. 2. Cane-Sugar (Common Sugar) : C]2TI10O]04-aq. 2. Cane-sugar, is found in sugar-cane, in sugar-maple [Acer saccha- rinum), and in other species of maple, in the red beet, and in the yellow, in several palms, in the nectar of flowers, etc., generally, inclosed in the cells in aqueous solution, with protein compounds and salts. Expressed sugar-juice soon commences fermentation at com¬ mon temperature, because its protein substances change into fer¬ ment. Hence, in its production, care must be taken soon to remove these protein substances, which is done by boiling up the juice with l-6th per cent, lime, straining and evaporating. The first crystals (muscovado) are purified by solution in water, treatment with ani¬ mal charcoal and recrystallization, whereby, however, one part of the sugar is converted into uncrystallizable sugar, especially if the evaporation be carried forward at a high temperature. By slow' evaporation of the pure sugar, solution we obtain large, regu¬ lar, well-formed crystals rock-candy) ; if, on the contrary, the crystallization be interrupted by stirring, we obtain aggregated small white crystals (loaf sugar). Sugar is dissolved in almost all proportions in water (syrup), and is also dissolved, abundantly, by alcohol, proportionate to the water it contains. Of all sugars, the cane species is the sweetest; it is unchangeable in the air, and phosphoresces strongly when rubbed. In the heat, a solution of sugar is, by degrees, converted into uncrystallizable sugar, and in proportion as this occurs, the power of rotation of polarized light diminishes. In the presence of alkalies this change takes place slowly ; on the contrary, very quickly under co-operation of acids. If the change has taken place, and the action continues, we ob¬ tain glucinic acid, humin substances, etc. If yeast be added to a solution of cane-sugar, fermentation soon commences, but previ¬ ously the cane-sugar is converted into grape and uncrystallizable sugar. Cane-sugar melts at 160°, and stiffens to a translucent, uncrystallizable mass (barley sugar); at a high temperature it assumes a brown color (caramel). 3. Fruit-Sugar: C12H12Ol2+x aq. is found in 3. Fruit.sugar. sweet lruits with grape-sugar. Honey is a mixture of Iruit-sugar and grape-sugar. Fruit-sugar appears also to bo