All =Beers=, =Ales=, and =Porters= are prepared from malt, which is the germinating grain of barley. The fermentation of the sugar in the barley produces alcohol, the amount of which varies in different cases. In Pilsener beer it is 3½ per cent. of absolute alcohol; in stout and porter 5 to 6 per cent. The hop which is added to the fermenting barley, gives to beer its characteristic bitterness. =London Porter= is coloured with black or roasted malt; =stout= is only a stronger form of porter. Bottled ales are generally stronger than those on draught, and being slightly effervescent, may agree better. The effect of alcohol in beer is modified by the _hops_, which help in producing drowsiness. Beer has a marked tendency to produce obesity, more so than any other alcoholic beverage. Its influence in the production of gout is also very great. =Substitutes for Malt= have been largely used. Thus by the action of sulphuric acid on starch, an artificial form of sugar is produced, which is largely used in place of malt for making beer. Many recent cases of poisoning by arsenic have been traced to the use of impure sulphuric acid in manufacturing this form of sugar. The detection of arsenic in organic liquids requires great care, as so many compounds of arsenic are volatile, especially in the presence of chlorides, as in beer. To _detect arsenic in beer_ a pint of the beer is evaporated to dryness, and treated with 20 c.c. of strong sulphuric acid, heated, and 20 c.c. of strong nitric acid added drop by drop. Violent action occurs: if possible 20 c.c. more of nitric acid are worked in. Transfer the liquid to a small flask, and expel the nitric acid by boiling. By this means all chlorine is expelled, the arsenic is oxidised and the organic matter destroyed. SH₂ gas is now passed into the acid liquid for some hours, the precipitated sulphur and any sulphide filtered off and extracted with ammonia, which dissolves any sulphide of arsenic. The liquid so obtained is subjected to Marsh’s test. (See page 216.)