The same is the case with the ascending sap of the birch-tree, but this does not contain sufficient sugar to permit the concentration of it; there is enough however to undergo the vinous fermentation, and thereby furnish the agreeable beverage called birth. wine.
Next to the sugars from the cane and beet-root, among those which aro crystallisable and capable of fermentation, the most important is the granular sugar obtained from a great variety of sources. It exists in considerable quantity in the juice of grapes, and hence the name grape sugar, which should be limited to this particular variety, is sometimes extended to the whole class of krummel sugars. It forps a constituent of a great many fruits, not merely fleshy, such as peals, cherries, peaches, melons, dates, figs, grapes, on which last two it forma a white incrustation when these are dried, but in chesnuts, when produced in warm regions. It exists in the nectaries of many flowers, and is collected by the bees; hence honey is only one of the kinds of this sugar. Though harmless in probably all instances to the bees, from whatever plant collected, it not =frequently has a poisonous influence over human beings, when it has been collected from poisonous plants, such as Rhododendrons and their allied genera.
Granular sugar is readily formed by the action of dilute sulphuric acid on starch, or sugar of milk, or the bastard sugar which remains after the finest refined sugar has been procured from the cline or been root sugar. Lignin, or anything containing or formed from it, such as saw-dust, linen-rags, or paper, may be likewise transformed into granular sugar. It is likewise the kind of sugar formed during the germination of seeds. Lastly, it is that kind of sugar which is formed by a perverted action of the digestive and assimilating organs in the disease termed diabetes mellitus. [ThassErEs.] All these varieties tasts leas sweet than the cane-sugar, and also differ among themselves ; thus grape and honey sugar are sweeter than that from starch, while starch sugar is sweeter than that obtained from juniper berries. All of them contain lege carbon and more water than the cane sugar, and mas be regarded as hydrates of sugar.
Sugar, which, though with difficulty crystallised, is referred to this section, exists in many fungi or mushrooms, especially of the genus Agaricua. While it contributes to their nutritive properties, it most ikely proves one source of the poisonous qualities they sometimes possess, as it is occasionally transformed into oxalic acid. Masses of
crystals have been observed on the cap of a mushroom, some of which sere sugar, while others were oxalic acid. Free oxalic acid is found in She Polyporus sulphureds,'Bull., which is most likely formed at the :xpense of the sugar.
The only uncrystallisable sugai which is capable of fermentation is the syrup which remains after the refining of the cane and other sugars. R. receives the name of molasses, and is used in medicine under the same of Sacchari faex, which is preferable to that of theriaca, as this might lead to confusion with a poisonous compound which bears a similar name. Molasses ere largely employed for the distillation pf runs.
The kinds of sugar =susceptible of fermentation are, the sugar of milk and marmite ; yet sugar of milk, when by the action of dilute sulphuric acid it is converted into granular sugar, is as susceptible of fermentation as any of the above-described. In other respects it conducts itself like common sugar, except that with nitric acid, besides oxalic acid, jt forms saclactic acid. It is procured from whey, either simply by evaporating to dryness (saccharum lactic inspis Saturn.), or by crystallising it. It is frequently separated from the curd by the addition of a great many substances, which can coagulate this, such as alum, vinegar, tamarinds, and mustard, and in certain diseases these medicated wheys are much recommended.
Sugar of milk has little sweetness, but a hot solution of it tastes much sweeter than the dry sugar. Sugar of milk is much used by the followers of hoinceopathy as the material of their dynam ised globules.
Manna sugar constitutes the greater portion of the manna which flows from the Ornus europaea and other ashes in the south of Europe, the bark of the olive-tree, many species of pines, the root and leaves of celery, the bulb of the common onion, and in the rhizome of the Triticum repens, or couch-grass. The sweet juices of many plants, such as beet, carrots, &c., when long exposed to the sir, generate manna sugar by a partial fermentation. To prevent this is one of the great objects in the manufacture rof beet-root sugar; hence the neces sity for speedily concentrating and purifying this juice. To this variety of sugar probably belongs Cynodon, which exists in the root of Digitaria (Cynodon) Dactylon. And also the principle called canellin, obtained from canella alba.