As the juice of these trees yields not more than about 2 per cent. of sugar, it requires for its solidification a large expenditure of fuel. The manufacture of maple sugar can therefore be advantageously carried on only in countries remote from markets whence ordinary sugar can be procured, or in regions where fuel is extremely plentiful. In North America it flourishes only between 40° and 43° N. lat. We are not aware of any estimate of the total production of maple sugar. The Census of Pennsylvania of 1870 gave the following figures as referring to its manufacture in that State:—
| 1850 | 1860 | 1870 |
| 2,326,525 lb. | 2,768,965 lb. | 1,545,917 lb.[2695] |
Sorghum—Another plant of the same order as Saccharum is Sorghum saccharatum Pers. (Holcus saccharatus L.) a native of Northern China,[2696] which has of late been much tried as a sugar-yielding plant both in Europe and North America; yet without any great success, as the purification of the sugar is accomplished with peculiar difficulty. As in the sugar cane, there are in sorghum crystallizable and uncrystallizable sugars, the former being at its maximum amount when the grain reaches maturity. The importance of the plant however is rapidly increasing on account of the value of its leaves and grain as food for horses and cattle, and of its stems which can be employed in the manufacture of paper and of alcohol.
Commerce—The value of the sugar imported into the United Kingdom is constantly increasing, as shown by the following figures:—
| 1868 | 1870 | 1872 | |
| Unrefined | £13,339,758 | £14,440,502 | £18,044,898 |
| Refined | £1,156,188 | £2,744,366 | £3,142,703 |
The quantity of Unrefined Sugar imported in 1872 was 13,776,696 cwt., of which about 3,000,000 cwt. were furnished by the Spanish West India Islands, 2,700,000 cwt. by the British West India Islands, 1,800,000 cwt. by Brazil, 1,100,000 cwt. by France, and 960,000 cwt. by Mauritius.
Of Refined Sugar the imports from France and Belgium into the United Kingdom were—
| 1874 | 1875 | 1876 |
| 133,800 | 102,300 | 92,044 tons. |
Uses—Refined sugar is employed in pharmacy for making syrups, electuaries and lozenges, and is useful not merely for the sake of covering the unpleasant taste of other drugs, but also on account of a preservative influence which it exerts over their active constituents.
Muscovado or Raw Sugar is not used in medicine. The dark uncrystallizable syrup, known in England as Molasses, Golden Syrup, and Treacle,[2697] and in foreign pharmacy as Syrupus Hollandicus vel communis, which is formed in the preparation of pure sugar by the influence of heat, alkaline bodies, microscopic vegetation, and the oxygen of the air, is sometimes employed for making pill masses. The treacle of colonial sugar alone is adapted for this purpose, that of beet root having a disagreeable taste, and containing from 19 to 21 per cent. of oxalate, tartrate and malate of potassium, and only 56 to 64 of sugar.[2698] The treacle of colonial sugar usually contains 5 to 7 per cent. of salts.