The Romance of Modern Chemistry

SUGAR AND STARCH to purify our best lump sugar, but thia is frequently the case. The reader need not trouble himself much about milk sugar, which forms 5 per cent, by weight of ordinary milk, or about malt sugar, which is formed from grain in the preliminary stages of brewing beer; but grape sugar or glucose is quite an important carbohydrate, and is worth a little attention. The very name suggests one of its sources, and as a matter of fact grapes contain 13 per cent, of glucose; the percentage present in dried fruits is much higher, and in figs is over 50. The bee must not be forgotten as an agent in the collec- tion of glucose, for honey contains 70 to 80 per cent, of this sugar. It comes originally, of course, from the flowers, and an estimate of the sugary matter in these has shown that the bees must visit several hundred thousand heads in order to collect one pound of honey. We pride our- selves, and justly, on the methods by which minute amounts of a precious metal can be extracted from large masses of rock and earthy material, but the remarkable achievement of the bee in the accumulation of almost microscopic quantities of sugar is probably unequalled. Glucose is not nearly so sweet as cane sugar, yet in the olden days, before cane sugar had been introduced, honey was the material used in sweetening dishes for the table. Later on, glucose was obtained from grapes, but nowadays it is made by boiling starch with dilute sulphuric acid; it is then known as “starch sugar.” It must be admitted that the names of the various sugars are a little confusing; already we have seen that beet sugar is the same as cane sugar, now it appears that starch sugar is nothing else than grape sugar. The starch required for the manufacture of glucose by 231