It has been already mentioned that the earliest beers were made without hops. After the use of this plant was discovered beer brewing as an art made rapid progress, and not only did every country make its own special sort of beer, but many varieties existed side by side in most of the German states and in England. Experiments were made with all sorts of grain, with potatoes and with plants and herbs, the object being in every case to produce a wort whose beer should have special advantages in point of flavor or cost or both. Gradually, however, most of the materials were quietly dropped, although potatoes are still used for the Strasbourg beer, and wheat forms an important element of the famous white beer of northern Germany. Barley is the grain that has universally been found best adapted to the purpose of making a brown beer of an agreeable flavor and of moderate price. With the question of material thus practically settled, it might be supposed that the difference between various brews of beer would disappear. On the contrary the number of varieties is to-day greater than ever before. Every step in the manufacture, from the selection of the grain and hops on to the final delivery of the product to the consumer, has something to do with the characteristics of the beer, and the difficulty does not lie in producing something new, but in reproducing accurately what has once been successfully tested. Whatever the distinguishing features of the product, it is still beer, and any one specimen of the genus has the general properties of all the others. All beer has a notably small percentage of alcohol, the strongest ales and porters showing less than many specimens of cider; all contain an appreciable amount of solid nutriment which in some heavy-bodied beers is quite considerable; all are palatable and wholesome, and all are adapted to take the place of ardent spirits and thus reduce intemperance and drunkenness to a _minimum_. It is hardly necessary to explain that in this book the word beer is used in its wide sense. When special varieties are meant they are spoken of by name unless the context is such as to remove all doubt.