The determination of the sulphuric acid can bo made directly by precipitation of the wine with barium chloride, but is much more conveniently and rapidly carried out as follows :

Take 14 grams of pure, dry, crystallized barium chloride, together with 50cc. hydrochloric acid, and make up to a liter. If 10cc. of wine are used, every 1cc. of this solution required indicates a content of 1 gram K2SO4 to the liter of wine; accordingly to several portions of wine of l0cc. each are added, respectively, 0.7, 1, 1.5, 2cc. and more if necessary, the solution heated, and allowed to stand. When cool they are filtered, and a little more barium chloride added to each test. The appearance or nonappearance of a further precipitate in the different tests will show between what limits the content of SO3 lies.

The use of starch sugar is also likely to introduce sulphates into the wine.

Fortification of wine consists in the addition of alcohol derived from gome other source. The alcohol may be added either to the must or the wine. It allows of better incorporation with the wine if it is added to the must before fermentation. In either case, however, it precipitates a part of the constituents originally dissolved, lowers the quantity of extract, deprives the wine of its original bouquet and flavor, and renders it more heady and intoxicating. The least objectionable addition is alcohol distilled from grapes; but the high price of the latter renders it much less likely to be used than corn spirit, which contains considerably more fusel oil. The practice of fortification prevails especially in the more southern wine-growing countries, as Portugal, Spain, and the South of France. Growers in those countries declare it to be a necessary addition in their warm climates for the preservation of the wines, as these latter contain a considerable quantity of unfermented sugar, which would soon produce the souring of the wine if the alcoholic content were not greater than can be obtained by fermentation. In France, for ordinary red wines, the addition of alcohol is decided by the relation of the alcohol to the extract (sugar deducted) exceeding sensibly the relation of 4 to 4.5. In Germany the relation of alcohol to glycerine is relied upon, the maximum proportion allowed being 100 parts by weight of alcohol to 14 of glycerine and the minimum 100 to 7. Wines going above the maximum are condemned as having suffered an addition of glycerine, those going below the minimum as being fortified with alcohol. With "sweet wines" these figures do not apply, as they are based on natural wines made in Germany. Moreover, no definite stand is taken upon the question of the fortification of the sweet wines from other countries sold in Germany. The Bavarian chemists require the content of alcohol and sugar in sweet wines used for medicinal purposes to be shown on the label, a very excellent provision, for no two samples of sweet wine can be depended upon to be of similar composition, and the physician is altogether in doubt as to what sort of a compound he is administering to his patient under the name of "port" or "sherry." Any wine with a higher percentage of alcohol than 15 per cent. by volume (12 per cent. by weight) can be safely declared to be fortified, for it has been shown that fermentation is arrested when the alcoholic content reaches about that point.

The preservative agents added to wine are entirely similar to those used in malt liquors. The subject of the use of salicylic acid has been so thoroughly investigated in the portion of the bulletin devoted to beer that a further treatment of the subject is unnecessary. The methods for detection and estimation already given for beer are applied equally as well to wine. The same may be said of sulphites and borax.

Mineral additions to wine are generally introduced accidentally, the strong acidity of the liquid making it very liable to contamination from metallic vessels, pipes, etc. Lead oxide was sometimes added to wine to counteract excessive acidity in former days, and Hassail gives cases of deaths traced to the use of such wines. Such additions belong probably to the adulterations of the past, although the possibility of such a contamination should never be forgotten, especially if any of the symptoms of lead poisoning have been produced by a suspected sample. The search for mineral constituents in wine presents no difficulties and need not be further dwelt upon.

Gummy substances are sometimes added to watered wines to make up for their deficiency in extract. Gum arabic, or commercial dextrin, have been used for this purpose. The addition may be detected by the following method, taken from the German Commission: "10cc. of 95 per cent. alcohol are added to 4cc. of wine and the whole well shaken; if gums are present the liquid becomes milky and does not clear up completely even after standing several hours. The precipitate formed adheres in part to the sides of the glass, and forms lumps. In genuine wines flakes form after a short time, which subside and remain rather loose. For a more exact test the wine should be evaporated to a sirup, extracted with alcohol, and the insoluble part dissolved in water. This solution is treated with 1cc. hydrochloric acid, heated under pressure for two hours and the reducing power ascertained with Fehling's solution. With genuine wines no considerable reduction is obtained in this way." I have made no trial of this method.

The adulteration of wines by substituting for it, wholly or in part, the fermented juices of other fruits, such as cider, is a matter difficult of detection. The presence in such wines of malic acid and the absence of tartaric was formerly considered a sufficient proof of the addition, but it is found that in bad years malic acid often predominates in grape juice, and on the other hand various causes may greatly reduce the content of bitartrate of potash, or even cause it to entirely disappear. The proof of such addition by chemical means rests chiefly upon con-clusions drawn from the general composition of the sample analyzed. Often the taste or odor of the residue of evaporation of the sample itself or of the distillate will give some clew to such addition. Often the recognition of free tartaric acid in such wines will condemn them as artificial, for natural wines contain a very small amount, if any, of the free acid; according to the German Commission never more than one-sixth of the total free fixed acids. Tartaric acid is often added also to wines which have been deprived of part of their normal acidity by the addition of water or sugar solutions. The qualitative determination is as follows: