The Romance of Modern Chemistry

THE ADULTERATION OF FOOD little genuine butter is melted in a large spoon over a small Bunsen flame, and the heating is continued, the butter ultimately boils quietly and foams up to the edge of the spoon. Margarine, treated in the same way, splutters about and crackles, but does not foam. The practice of selling margarine under the name of pure butter is probably dying out, but it is not so very long since a bold individual was prosecuted for actually ad- vertising a process for the “scientific” blending of butter with beef fat or lard. Science, it would seem, covers a multitude of sins. A food-stuff which is very frequently adulterated is chocolate. This substance is obtained by grinding cocoa nibs, which are the crushed kernels of cocoa beans. The nibs consist to about 45 per cent, of a fat, the so-called cocoa butter, and in this respect are quite different from the shells of the cocoa bean, which contain only 2 to 3 per cent, of the fat. Seeing that the price of cocoa nibs is about ten times that of cocoa shells, the common practice of adulterating chocolate with powdered cocoa shells is distinctly profitable. This fraud is best de- tected by the aid of the microscope, an instrument which is part of the necessary equipment of an analytical chemist’s laboratory. To the practised eye the presence of the powdered shells is at once obvious. There is another adulterant of chocolate or cocoa which is easily detected with the aid of the microscope, and that is starch. This substance is very widely distributed in the plant world, and occurs in all sorts of vegetables and cereals. The samples of starch obtained from these various sources, such as wheat, rice, potatoes, and maize, are chemically identical, but when they are examined under the microscope, the granules of which they consist 265