The art of canning and preserving food in some form or another is one which has been practised since the early days, and is almost as old as history itself. However, in those days they did not know the "reasons why and wherefore," which have only of recent years been revealed to us by Science. Long before people had any knowledge of germs or microbes it was discovered that fruit and vegetables could be readily kept for an almost indefinite period in a heavy solution of sugar, or in a strong acid or vinegar, and thus resulted the pickles of various kinds, and the compositions, pound for pound, of sugar and fruit, which we call preserves, jams, marmalades, and jellies.