Consists of a compound of crushed mustard seed and vinegar, the seed having been passed between rollers and then washed into a cask or vat. With it there is often mixed garlic and such spice or flavoring material as the fancy or experience of the manufacturer will determine. This compound is ground two or three times through a stone mill or through a line of several mills, the material being fed from one to the other until it is received in a final reservoir, from which it is put up in bottles. It is of a consistency of paste, which contains all the mustard, the oil, the flour, and the bran. It may be compounded with an indefinite variety of material, and the refuse bran of dry mustard may also be added. Its use is steadily increasing, and a very satisfactory article may be made at home by thoroughly pounding the seed and mixing it with good vinegar. In this way the maker can be sure that his compound has the virtue of purity and also of cheapness. As the fixed oil has no pungency or mustard taste, it adds nothing to the flavor of the flour, but, instead, injures its keeping qualities, and, if left in, makes the seed very difficult to be pulverized. It is used as a salad and there is a ready market for it, as there is a great demand for it by the Jewish people. Since hydraulic presses are expensive, costing from $2,000 to $4,000 each, but a small number of the spice millers press their own mustard seed. They either buy the mustard cake, which has been prepared by special mustard mills, or buy the pure or adulterated flour, already prepared for the market. Some spice millers are suspicious of the cake, fearing it may be adulterated or be made up of partially poor seed, or of the refuse of previous workings, and they have good reasons for their fears, as such adulteration might occur, but as the pure article is to be judged by the flavor and pungency it may possess, it is as easy to test the cake as the seed. Mustard is not only very popular as a condiment but is a medicinal rubefacient, as it has many stimulating properties. The use of mustard plasters every household is familiar with; mustard also promotes digestion, and it is a splendid emetic in case of poisoning. A good story is told of a quack doctor who advertised electric belts for sale. He had received many testimonials from those who had bought them, his patrons speaking very highly of the benefit they had received from their use, but as the belts became worn and were ripped open it was found that the electricity they contained was made up of mustard flour. In the ground mustard or mustard meal, as has been explained, we have only the interior of the seed, with the exception of the few small portions of the husk, which may have escaped in the operation of bolting. The presence of these fragments enables us to recognize the source from which the flour is derived, and also to detect the use of mustard hulls as an adulterant of other food materials.