Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/187

Rh ADULTEKATION 171 the Pillory and Tumbrel (51 Henry III. stat. 16) already mentioned. In the city of London, according to &quot; Liber Albus,&quot; the assize of bread was an important institution. It was always made immediately after the feast of St Michael in each year, and very specific instructions were given for the guidance of the four discreet men who were to perform it ; for their decision regulated the business of the baker in respect of the price and quality of bread, &amp;lt;fcc., for the current year; and woe to him if he disregarded it there being numerous instances in &quot; Liber Albus&quot; of the pillory and the thew in cases where bread had been found adulterated or of short weight. In the time of Anne, the assize of bread was still further regulated (8 Anne, c. 19), and in the year 1815 it was abolished by the statute 55 Geo. III. c. 99. Especial provision, however, was made to guard against the frauds of adulteration, for several Acts of Parliament, especially 31 Geo. II. c. 29 and 1 and 2 Geo. IV. c. 50, prohibited the use of alum and other spurious articles in bread under severe penalties. At the present time, the chief adulterations of bread are with alum or sulphate of copper for the purpose of giving solidity to the gluten of damaged or inferior flour, or with chalk or carbonate of soda to correct the acidity of such flour, or with boiled rice or potatoes to enable the bread to carry more water, and thus to produce a large number of loaves per sack of flour. In practice 100 Ibs. of flour will make from 133 to 137 Ibs. of bread, a good average being 136 Ibs. ; so that a sack of flour of 280 Ibs. should yield 95 four-pound loaves. But the art of the baker is exercised to increase the number, and this is accomplished by harden ing the gluten in the way already mentioned, or by means of a gummy mess of boiled rice, three or four pounds of which, when boiled for two or three hours in as many gallons of water, will make a sack of flour yield at least 100 four-pound loaves. Such bread, however, is always dropsical, and gets soft and sodden at the base on standing, and quickly becomes mouldy. A good loaf should have kindness of structure, being neither chaffy, nor flaky, nor crummy, nor sodden. It should also be sweet and agreeable to the palate and the nose, being neither sour nor mouldy. It should keep well, and be easily restored to freshness by heating it in a closed vessel. And a slice of it, subjected to a temperature of from 260 to 280 Fahr. should hardly be discoloured, and should not lose more than 37 or 38 per cent, of its weight. When steeped in water, it should give a milky sweet solution, and not a ropy acid liquid. The recognition of alum and sulphate of copper in bread requires practice and skilful manipulation, it being surrounded with difficulties. The most easily applied process is that described by Mr Horsley. He makes a tincture of logwood, by digesting a quarter of an ounce of the freshly cut chips in five ounces of methylated spirit for eight hours, and filters. A teaspoonful of this tincture is put with a like quantity of a saturated solution of carbonate of ammonia into a wine-glassful of water ; and the mixed solutions, which are of a pink colour, are then poured into a white-ware plate or dish. A slice of the suspected bread is allowed to soak in it for five minutes, after which it is placed upon a clear plate to drain, and, if alum be present, it will, in the course of an hour or two, acquire a blue colour ; if the tint be greenish, it is a sign of sulphate of copper ; whereas pure bread gradually loses its pink colour, but never becomes blue or green. The ash of bread will also furnish evidences of the presence of mineral impurities. 6. Flour and other Farinaceous Matters. The tests for good flour are its sweetness and freedom from acidity and musty flavour. A given weight of the flour, say 500 grains, made int a stiff dough with water, and then carefully kneaded under a small str.am of water, will yield a tough elastic gluten, which, when baked in an oven, expands into a clean-looking ball of a rich brown colour, that weighs, when perfectly dry, not less than 50 grains. Bad flour makes a ropy-looking gluten, which is very difficult of manipulation, and is of a dirty brown colour when baked. The ash of flour should not exceed 2 per cent. Other farinaceous matters are recognised under the microscope by the peculiar form, and size, and marking of the individual granules. In this way, the adulterations of oat-meal with barley-meal, and of arrow-root with inferior starches, may be easily detected. 7. Fatty Matters and Oils are the subjects of frequent adulteration. Butter and lard, for example, are mixed with inferior fats, and with water, salt, and farina. Most of these impurities are seen when the sample of butter or lard is melted in a glass, and allowed to stand in a warm place for a few hours, when the pure fat will float as a transparent oil, while the water, salt, farina, &c.,will subside to the bottom of the glass. Fresh butter generally contains a notable quantity of water, as from 12 to 13 per cent.,, and sometimes a little salt, and a trace of curd ; but these should never exceed two per cent, in the aggregate. Foreign fats are recognised by the granular look of the butter, by its gritty feel, by its taste, and by its odour when wanned. Other tests for these impurities are the melting-point of the sample, and its solubility in a fixed quantity of ether at a temperature of 65 Fahr. 20 grains of the sample, treated with a fluid drachm of ether, in a closed test tube, will look slighty flocculeut,and be almost entirely dissolved in the case of good butter ; but it will be mealy and liniment-like with lard, granular with dripping, and almost solid with mutton fat. The melting point of different fats is as follows : Horse grease, 140; calf fat, 136; mutton fat, 130; beef fat, 99; hog s lard, 81; and butter, 80. Oils are adulterated with inferior kinds, and the fraud is detected by means of the specific gravity of the oil, and its chemical reactions when tested upon a white plate with a drop of concentrated sulphuric acid the colour and its time of development being the indications of the quality of the oil. The specific gravity of the animal oils are as follows : Neat s-foot oil, 880 ; tallow oil, 900 ; dolphin oil, 918; cod-liver oil, 921 to 926; whale oil, 927; seal oil, 934 ; porpoise oil, 937. Among the vegetable oils the following are the most important : Rape or colza oil, 913 to 91 6; olive oil, 918; filbert oil, 916; beech-nut, 922; walnut, 923 ; cotton-seed, 923 to 928 ; poppy, 924 ; sweet almond, 918 to 922; hazel-nut and hemp-seed, 926; and linseed, 634 to 936. 8. Isinglass is often adulterated with gelatine, the fraud being ingeniously contrived so as to retain to a large extent the well-known characters of genuine isinglass ; but it may be recognised in the following way : immersed in cold water, the shreds of genuine isinglass become white and opaque like cotton threads, and they swell equally in all directions, whereas those of gelatine become transparent and ribbon- like. Isinglass dissolves completely in boiling water, and makes a slightly turbid solution, which has a faint fishy smell, and is without action on litmus paper; whereas gelatine leaves a quantity of insoluble matter, and the solution smells of glue, and has an acid reaction. Strong acetic acid swells up the shreds of isinglass, and renders them soft and gelatinous ; but it hardens gelatine. And, lastly, the ash of genuine isinglass is very small in quantity, and has a reddish colour ; whereas that of gelatine is bulky (weighing from 2 to 3 per cent.), and has a perfectly white appearance from the presence of calcareous salts. Genuine isinglass is produced from the swimming-bladder or sound of the sturgeon, but gelatine is a sort of clarified glue- obtained from bones, clippings of hides, &amp;lt;fcc. Boussingaulfc. states tlu,t the Bouzwiller glue, which is prepared from the-