Foods such as Potatoes, Rice, Peas, Bulk of Wheat and Other Grains; all comes under the category of Starch Foods. The starches can be digested only after they are turned into sugars in the body. If you put salt with sugar or starch, although it will mix perfectly and give its taste to the mixture, neither the salt nor the starch nor the sugar will have changed at all, but will remain exactly as it was in the first place, except for being mixed with the other substances. But if you were to pour water containing an acid over the starch, and then boil it for a little time, your starch would entirely disappear, and something quite different take its place. This, when you tasted it, you would find was sweet; and, when the water was boiled off, it would turn out to be a sugar called glucose. Again, if you should pour a strong acid over sawdust, it would “char” it, or change it into another substance, carbon. In both of these cases — that of the starch and of the sawdust–what we call a chemical change would have take