A Treatise on Adulterations of Food, and Culinary Poisons | Page 5

for in its natural state. The price of the best genuine bark, upon an average, is not lower than twelve shillings the pound; but immense quantities of powder bark are supplied to the apothecaries at three or four shillings a pound.
It is also notorious that there are manufacturers of spurious rhubarb powder, ipecacuanha powder,[2] James's powder; and other simple and compound medicines of great potency, who carry on their diabolical trade on an amazingly large scale. Indeed, the quantity of medical preparations thus sophisticated exceeds belief. Cheapness, and not genuineness and excellence, is the grand desideratum with the unprincipled dealers in drugs and medicines.
Those who are familiar with chemistry may easily convince themselves of the existence of the fraud, by subjecting to a chemical examination either spirits of hartshorn, magnesia, calcined magnesia, calomel, or any other chemical preparation in general demand.
Spirit of hartshorn is counterfeited by mixing liquid caustic ammonia with the distilled spirit of hartshorn, to increase the pungency of its odour, and to enable it to bear an addition of water.
The fraud is detected by adding spirit of wine to the sophisticated spirit; for, if no considerable coagulation ensues, the adulteration is proved. It may also be discovered by the hartshorn spirit not producing a brisk effervescence when mixed with muriatic or nitric acid.
Magnesia usually contains a portion of lime, originating from hard water being used instead of soft, in the preparation of this medicine.
To ascertain the purity of magnesia, add to a portion of it a little sulphuric acid, diluted with ten times its bulk of water. If the magnesia be completely soluble, and the solution remains transparent, it may be pronounced pure; but not otherwise. Or, dissolve a portion of the magnesia in muriatic acid, and add a solution of sub-carbonate of ammonia. If any lime be present, it will form a precipitate; whereas pure magnesia will remain in solution.
Calcined magnesia is seldom met with in a pure state. It may be assayed by the same tests as the common magnesia. It ought not to effervesce at all, with dilute sulphuric acid; and, if the magnesia and acid be put together into one scale of a balance, no diminution of weight should ensue on mixing them together. Calcined magnesia, however, is very seldom so pure as to be totally dissolved by diluted sulphuric acid; for a small insoluble residue generally remains, consisting chiefly of silicious earth, derived from the alkali employed in the preparation of it. The solution in sulphuric acid, when largely diluted, ought not to afford any precipitation by the addition of oxalate of ammonia.
The genuineness of calomel may be ascertained by boiling, for a few minutes, one part, with 1/32 part of muriate of ammonia in ten parts of distilled water. When carbonate of potash is added to the filtered solution, no precipitation will ensue if the calomel be pure.
Indeed, some of the most common and cheap drugs do not escape the adulterating hand of the unprincipled druggist. Syrup of buckthorn, for example, instead of being prepared from the juice of buckthorn berries, (rhamnus catharticus,) is made from the fruit of the blackberry bearing alder, and the dogberry tree. A mixture of the berries of the buckthorn and blackberry bearing alder, and of the dogberry tree, may be seen publicly exposed for sale by some of the venders of medicinal herbs. This abuse may be discovered by opening the berries: those of buckthorn have almost always four seeds; of the alder, two; and of the dogberry, only one. Buckthorn berries, bruised on white paper, stain it of a green colour, which the others do not.
Instead of worm-seed (artemisia santonica,) the seeds of tansy are frequently offered for sale, or a mixture of both.
A great many of the essential oils obtained from the more expensive spices, are frequently so much adulterated, that it is not easy to meet with such as are at all fit for use: nor are these adulterations easily discoverable. The grosser abuses, indeed, may be readily detected. Thus, if the oil be adulterated with alcohol, it will turn milky on the addition of water; if with expressed oils, alcohol will dissolve the volatile, and leave the other behind; if with oil of turpentine, on dipping a piece of paper in the mixture, and drying it with a gentle heat, the turpentine will be betrayed by its smell. The more subtile artists, however, have contrived other methods of sophistication, which elude all trials. And as all volatile oils agree in the general properties of solubility in spirit of wine, and volatility in the heat of boiling water, &c. it is plain that they may be variously mixed with each other, or the dearer sophisticated with the cheaper, without any possibility of discovering the abuse by any of the before-mentioned trials. Perfumers