The percentage of alcohol in different liquids is shown in the following table : In examining wine three ounces may be used and two distilled. Half the quantity of beer need only be distilled. Neutralize the free acid in the liquor before distilling. Gin is spirit of wine flavoured with juniper berries, coriander seeds, grains of paradise, &c. I think it is rare'y adulterated with any injurious substance. Brandy is often adulterated with corn spirit, and, therefore, frequently contains fusel oil. It is generally mixed with a little syrup. Rum is adulterated with corn spirit and molasses. Its flavour is said to be chiefly due to butyric ether. Wines. I am disposed to think that wines are not much adulterated. Different varieties and qualities of wine are mixed ("blended"); but that can hardly be regarded as a falsification. Claret, I have no hesitation in asserting, is exceedingly rarely adulterated, even when it is sold at a shilling per bottle. The quality of wine is, however, often very bad. Port and sherry contain a large amount of added alcohol; but everyone knows this. The examination of wine is usually limited to ascertaining the amount of alcohol, acid, sugar, and extractive which it contains. The acidity of wines and other liquids may be determined as follow:-Dissolve 63 grammes of crystallized oxalic acid in one litre of water. A solution of caustic soda is graduated with this acid solution, so that 1 c. c. of the one exactly neutralizes 1 c. c. of the other. In preparing the standard solution of soda, if, say, 7 cubic centimetres of the preliminary solution neutralize 10 c.c. of the acid solution, then add 30 per cent. of water to the alka. line solution. One c.c. of alkaline solution equals 0051 gramme of anhydrous and 006 gramme of glacial acetic acid, '019? gramme citric acid, .015 gramme tartaric acid, and .0049 gramme oil of vitriol. The amount of acidity is ascertained by distilling a portion of the wine (if the colour be high), making up the distilĴate to the original volume of the liquid used. Ten c.c. of the liquid are then taken, and the alkaline solution dropped into it until neutralization takes place. The number of c.c. used, mul tiplied by the co-efficient of say glacial acetic acid, gives the total amount of acidity in the quantity of wine operated on. By a simple calculation the amount per ounce or pint may next be ascertained. The point of neutralization is ascertained by colouring the liquid to be tested with litmus. The acid reddens this reagent; but so soon as the acid is neutralized the litmus re-acquires its blue hue. There are several acids in wine; but it will be sufficient to estimate all as tartaric. is determined as in the case of milk. the copper solution. The amount of solid matter Wines contain variable quantities of fruit sugar, albuminous bodies, vegetable acids, and other matters. The sugar varies from a mere trace to 25 grains per ounce of 480 grains. Mazanilla and Amontillado contain only from 1 to 8 grains per ounce; Marsala and Madeira, 3 to 35 grains; Port, 15 to 35 grains; Champagne, from 10 to 40 (average about 28) grains. Sugar is added to sparkling Champagne and Moselle. In Claret, Burgundy, and Hock there is little or no sugar. According to Bence Jones, wines stand, with respect to acidity, in the following order, those most acid being placed first:Sherry, Port, Champagne, Claret, Madeira, Burgundy, Rhine wine, Moselle. The albuminous matters in wine are unimportant. The flavour and odour are in great part due to peculiar substances termed compound æthers, of which there appear to exist a large number. The salts consist of cream of tartar and other compounds of potassium, tartrate of lime (calcic tartrate), salt, and some other matters, making in all about 1 grain per ounce of wine. The matter obtained by evaporating an ounce of wine to dryness weighs. from 15 to 50 grains. The free acid amounts to from 2 to 4 grains per ounce in Claret, 1 to 3 grains in Sherry, 2 to 4 grains in Port, 1 to 4 grains in Rhine wines, and two to four grains in Champagne. Larger quantities than these injure the quality of the wine very seriously, and much larger amounts-6 or 8 grains per ounce-utterly spoil them. The spirit distilled from wine when rubbed on the hand exhales the odour of whiskey or other corn spirit, elder berries, &c., if any of the latter substances had been used as adulterants. When to wine is added one-fourth of its bulk of a strong solution of alum, and, secondly, an equal volume of strong solution of carbonate of ammonium, a red or purplish colour is produced if logwood, Brazil wood, elder berries, and some other substances be present, but if not, the wine acquires a dirty greenish hue. Alum, lead, and copper may be detected by evaporating two ounces of the wine to dryness, burning the residue, and examining the ash for these substances, according to the method already described, p. 86. Beer. I have only met with one case of adulterated porter. In England it is said that beer is adulterated with salt, grains of paradise, burnt sugar, alum, cocculus indicus, lime, soda, me allic salts, and various other matters. The extract obtained by evapo. 324 Vinegar-Metric Weights and Measures. rating beer, if closely examined and tested, reveals the presence of some of these adulterants. Cocculus indicus appears to be rather a frequently used adulterant. Herepath gives the following mode of detecting its active principle, picrotoxin :-Treat the beer with solution of sugar of lead, filter, precipitate the lead with sulphuretted hydrogen, concentrate to a small volume, and filter the liquid through animal charcoal. The picrotoxin is retained by the charcoal, from which, when dried, boiling alcohol extracts it and from the alcohol it may be obtained in tufts of crystals by evaporation in a little watch glass. Picrotoxin when treated successively with 3 or 4 parts of pure nitre, a drop or two of sulphuric acid, and an excess of solution of caustic potash, produces a bright yellow colour; solution of picrotoxin in sulphuric acid gives, when touched with bichromate of potassium, a violet hue, which soon changes into brown and green. Vinegar is, according to law, allowed to contain 1 part per 1,000 of sulphuric acid. A larger proportion may be detected by the soda solution, when the acetic acid has been expelled by boiling. Vinegar should contain at least 4 per cent. of acetic acid. TABLE Of Decimal Weights and Measures, and their Equivalents. I Mètre I Decimètre I Centimètre 39.37079 inches 3.937079 "" I Millimètre I Cubic centimètre I Litre I Milligramme 1 Centigramme I Decigramme I Gramme I Killogramme = 1.543234 grains 15.432348 15432.348 A gramme weighs I cubic centimètre of distilled water at 4° centigrade, or 39.2° Fahr. ; but in working with test solutions, it is better to have the cubic centimètre equal to I gramme at 60° Fahr., the most usual temperature in the laboratory. Disinfection by Gases. 325 APPENDIX. DISINFECTION BY GASES. The following constitutes a portion of a paper on Disinfection, which I read at a meeting of the Medical Society of the King and Queen's College of Physicians in 1872: As generally performed, disinfection by gases is by no means efficacious. This, I think, I have proved by showing that even considerable quantities of chlorine and sulphurous acid do not kill the bacteria which are usually associated with putrefaction, nor perfectly destroy the contagious matter of at least one zymotic disease.i Several watch and microscopic object glasses were dipped into filtered beef-tea, which contained enormous numbers of bacteria, and whilst still moist they were placed in different positions in a hood, or small chamber made of wood and glass, containing 16 cubic feet of space. Half an ounce of chloride of lime was placed in a capsule and introduced into the hood, and an equivalent quantity of hydrochloric acid was poured on the powder in such a way as to prevent the chlorine evolved from passing out of the hood. After the lapse of twenty-four hours the door of the hood was opened and the glasses removed. They were found to be covered with extremely thin films of solidified beef extract. A few drops of pure water were used to render the film semi-liquid, and its contents were examined with a microscopic power of 800 diameters. In a few seconds the bacteria were detected moving about with great rapidity, and with apparently undiminished vigour. It was clear, then, that fumigation at the rate of a little more than three ounces of bleaching powder per 100 cubic feet of space had no effect in destroying bacteria. The hood was more air-tight than a room is when its doors, windows, and fire-place are closed. On opening the door of the hood after twenty-four hours the odour of chlorine was distinctly perceived at a distance of several feet. If a room 15 feet long, 10 feet wide, and 10 feet high, and having, therefore, a capacity of 1,500 cubic feet, were disinfected by chloride of lime in the relative proportions employed in the foregoing experiment, it would be necessary to use nearly three pounds of chloride of lime. As the gases evolved from three ounces of bleaching powder per 100 cubic feet of space did not destroy bacteria, an experiment was On the Application of Gases as a Means of Destroying Contagion. By Charles A. Cameron, M.D. Dublin Journal of Medical Science, June, 1872 |